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Veliparib in Combination with Carboplatin and Etoposide in Patients with Treatment-Naïve Extensive-Stage Small Cell Lung Cancer: A Phase 2 Randomized Study
Abstract
Purpose:
This study investigated the efficacy and safety of oral PARP inhibitor veliparib, plus carboplatin and etoposide in patients with treatment-naïve extensive-stage small cell lung cancer (ED-SCLC).
Experimental design:
Patients were randomized 1:1:1 to veliparib (240 mg twice daily [BID] for 14 days) plus chemotherapy followed by veliparib maintenance (400 mg BID; veliparib throughout), veliparib plus chemotherapy followed by placebo (veliparib combination only), or placebo plus chemotherapy followed by placebo (control). Patients received 4-6 cycles of combination therapy, then maintenance until unacceptable toxicity/progression. The primary endpoint was progression-free survival (PFS) with veliparib throughout versus control.
Results:
Overall (N=181), PFS was improved with veliparib throughout versus control (hazard ratio [HR] 0.67 [80% confidence interval (CI): 0.50-0.88], P=0.059); median PFS was 5.8 and 5.6 months, respectively. There was a trend towards improved PFS with veliparib throughout versus control in SLFN11-positive patients (HR 0.6; 80% CI: 0.36-0.97). Median overall survival (OS) was 10.1 versus 12.4 months in the veliparib throughout and control arms, respectively (HR 1.43, 80% CI: 1.09-1.88). Grade 3/4 adverse events were experienced by 82%, 88%, and 68% of patients in the veliparib throughout, combination only, and control arms, most commonly hematologic.
Conclusions:
Veliparib plus platinum chemotherapy followed by veliparib maintenance demonstrated improved PFS as first-line treatment for ED-SCLC with an acceptable safety profile, but there was no corresponding benefit in OS. Further investigation is warranted to define the role of biomarkers in this setting.
... Ten reports were excluded due to the absence of a control arm [22][23][24][25][26][27][28][29][30][31], two studies had insufficient data [32,33], one study was excluded as the comparison between the intervention and control arms was inappropriate [34], one study was not a clinical trial [35], and one study was a reanalysis of a previous study [36]. After the exclusion of 15 studies, the remaining seven studies met the eligibility criteria and were included in our review [37][38][39][40][41][42][43] (Fig 1). ...
... In one study (Argiris et al.) there were two phases, the first of which was conducted without a control arm [37]. The included studies consisted of one open-label [43], one single-blind [37], and five remaining studies were all double-blind [38][39][40][41][42]. The sample size of the included studies ranged from 21 to 970 participants, while the follow-up duration ranged from 10-12 weeks to four years. ...
... However, all studies had a low risk of bias in the missing outcome data. In addition, the majority of the included studies [37][38][39][40][41][42] (all but one) [43] were rated as having a low risk of bias in the selection of the reported results (Fig 2 and S2 Table). ...
Background:
As a poly-ADP ribose polymerase (PARP) inhibitor, veliparib has been identified as a potential therapeutic agent for lung cancer. The present study aimed to conduct a systematic review of clinical trials investigating the efficacy and safety of veliparib for treating lung cancer.
Methods:
PubMed, Scopus, the Web of Science, and Google Scholar were systematically searched up to October 30, 2022. Only randomized controlled trials (RCTs) evaluating the efficacy or safety of veliparib in the treatment of lung cancer patients were included. Studies were excluded if they were not RCTs, enrolled healthy participants or patients with conditions other than lung cancer, or investigated therapeutic approaches other than veliparib. The Cochrane risk-of-bias tool was used for quality assessment.
Results:
The seven RCTs (n = 2188) showed that patients treated with a combination of veliparib and chemotherapy had a significantly higher risk of adverse events, when compared to the control arm. There was no statistically significant difference in overall survival (OS) between those treated with veliparib plus chemotherapy and those receiving the standard therapies. Only two trials demonstrated an improvement in progression-free survival (PFS), and only one study found an increase in objective response rate (ORR). Furthermore, adding veliparib to standard chemotherapy showed no benefit in extending the duration of response (DoR) in any of the studies.
Conclusions:
Only a small number of studies have found veliparib to be effective, in terms of improved OS, PFS, and ORR, while the majority of studies found no benefit for veliparib over standard treatment.
... Different combinations of PARPis and chemotherapeutic agents have been tested in phase I/II studies, showing signals of anti-tumor activity [73][74][75][76]. The rationale for their combination lies in the fact that the chemotherapeutic agents might enhance the efficacy of PARP inhibition by causing single-strand DNA damage [74]. ...
... The rationale for their combination lies in the fact that the chemotherapeutic agents might enhance the efficacy of PARP inhibition by causing single-strand DNA damage [74]. While veliparib plus platinum-based chemotherapy has been tested as a frontline treatment of SCLC [75,76], PARPi-chemotherapy combinations might find their place in the relapse setting when patients who initially responded to DNA-damaging agents eventually progress. In order to identify subsets of patients that might benefit the most from these combination strategies, as previously mentioned, the expression of SLFN11 might serve as a predictive marker for response to both platinum-based chemotherapy and PARP inhibition, and the identification of common features associated with platinum-based resistance, and suggesting consequential PARPi chemotherapy resistance, is a huge area of research [73,74]. ...
Small cell lung cancer (SCLC) has been historically considered a homogeneous disease and thus approached as a single entity when it comes to clinical studies design and new treatments developments. However, increasing knowledge in the genetic and molecular landscape of this disease challenges this concept, opening the possibility that different subtypes might show differential vulnerability to treatments. In this narrative review, we gather the most relevant advances in genetic and molecular characterization of SCLC, focusing on how these discoveries may be used to design the path for a personalized treatment approach. Indeed, we discuss the new classification based on differential protein expression, the prevalence and significance of oncogenic drivers (e.g., EGFR mutations and ALK rearrangements) in SCLC, the genetic characteristics of SCLC in patients with no smoking history, and the existing evidence supporting the use of liquid biopsy for capturing the heterogeneity of the disease. We use the keywords "small cell lung cancer", "SCLC", "EGFR", "ALK", "histological transformation", and "transcriptional factors" to identify original research manuscripts, clinical trials, case reports, and case series from PubMed.
... In this study, we also found that SCLC models with high levels of SLFN11 protein were more sensitive to lurbinectedin. Previous studies from our group and others have shown that SLFN11 predicts sensitivity to some DNA damaging agents (e.g., cisplatin and PARP inhibitors), but not others (e.g., temozolomide) (10,12,25,(27)(28)(29)(30)(31). Recently, our group developed a CLIAcertified immunohistochemistry (IHC) assay (12) for SLFN11 for a cooperative group trial testing the activity of PARP inhibitors in a SLFN11-positive patient population (SWOG1929/NCT04334941). ...
... SLFN11 has recently emerged as a promising predictive biomarker in SCLC, predicting response to a wide range of DNA-damaging chemotherapies and PARPi. SLFN11 detection by IHC has been validated and evaluated in several clinical trials retrospectively (12,27). The first clinical trial in SCLC selecting patients for SLFN11positive tumors is currently ongoing (SWOG1929/ NCT04334941), which uses a CLIA-certified SLFN11 IHC assay. ...
Background:
Lurbinectedin recently received FDA accelerated approval as a second line treatment option for metastatic small cell lung cancer (SCLC). However, there are currently no established biomarkers to predict SCLC sensitivity or resistance to lurbinectedin or preclinical studies to guide rational combinations.
Methods:
Drug sensitivity was assayed in proliferation assays and xenograft models. Baseline proteomic profiling was performed by reverse-phase protein array. Lurbinectedin-induced changes in intracellular signaling pathways were assayed by Western blot.
Results:
Among 21 human SCLC cell lines, cytotoxicity was observed following lurbinectedin treatment at a low dose (median IC50 0.46 nM, range, 0.06-1.83 nM). Notably, cell lines with high expression of Schlafen-11 (SLFN11) protein, a promising biomarker of response to other DNA damaging agents (e.g., chemotherapy, PARP inhibitors), were more sensitive to single-agent lurbinectedin (FC =3.2, P=0.005). SLFN11 was validated as a biomarker of sensitivity to lurbinectedin using siRNA knockdown and in xenografts representing SLFN11 high and low SCLC. Replication stress and DNA damage markers (e.g., γH2AX, phosphorylated CHK1, phosphorylated RPA32) increased in SCLC cell lines following treatment with lurbinectedin. Lurbinectedin also induced PD-L1 expression via cGAS-STING pathway activation. Finally, the combination of lurbinectedin with the ataxia telangiectasia and Rad3-related protein (ATR) inhibitors ceralasertib and berzosertib showed a greater than additive effect in SLFN11-low models.
Conclusions:
Together our data confirm the activity of lurbinectedin across a large cohort of SCLC models and identify SLFN11 as a top candidate biomarker for lurbinectedin sensitivity. In SLFN11-low SCLC cell lines which are relatively resistance to lurbinectedin, the addition of an ATR inhibitor to lurbinectedin re-sensitized otherwise resistant cells, confirming previous observations that SLFN11 is a master regulator of DNA damage response independent of ATR, and the absence of SLFN11 leads to synthetic lethality with ATR inhibition. This study provides a rationale for lurbinectedin in combination with ATR inhibitors to overcome resistance in SCLC with low SLFN11 expression.
... Based on the findings in cancer cells-based models, the clinical exploitation of SLFN11 expression as a treatment biomarker is being actively explored. Cancer patients whose tumors show high SLFN11 expression show better chemotherapy response to PARP inhibitors, irinotecan, and temozolomide in recurrent or refractory solid tumors such as Ewing sarcoma and small cell lung cancers (SCLCs) [138][139][140]. SLFN11 is positively linked to stromal signatures of basal-like phenotype and estrogen receptor negative (ER-) type in breast cancer [141]. ...
... With regards to translating SLFN11 to the clinic, reliable approaches are required to evaluate the SLFN11 status of tumor tissues and circulating tumor cells (CTCs) ( Figure 6A). Studies performed at different cancer research centers have established the feasibility of immunohistochemistry (IHC)-based detection of SLFN11 in malignant and adjacent normal tissues [9,11,100,120,138,[140][141][142][143]145]. SLFN11 expression by IHC is also underinvestigation in CTCs from advance prostate cancer and SCLC patients [144,146]. ...
Precision medicine aims to implement strategies based on the molecular features of tumors and optimized drug delivery to improve cancer diagnosis and treatment. DNA replication is a logical approach because it can be targeted by a broad range of anticancer drugs that are both clinically approved and in development. These drugs increase deleterious replication stress (RepStress); however, how to selectively target and identify the tumors with specific molecular characteristics are unmet clinical needs. Here, we provide background information on the molecular processes of DNA replication and its checkpoints, and discuss how to target replication, checkpoint, and repair pathways with ATR inhibitors and exploit Schlafen 11 (SLFN11) as a predictive biomarker.
... A modest improvement in PFS was demonstrated without a corresponding benefit in OS. The group receiving veliparib in combination with chemotherapy had a median PFS of 5.8 months, while the median PFS in the subjects administered placebo plus chemotherapy, followed by the placebo, reached 5.6 months [41]. Another randomized, double-blind phase 2 trial evaluated whether adding veliparib to temozolomide (TMZ) would improve 4-month disease progression-free survival in 104 patients with relapsed SCLC [42]. ...
Lung cancer has become a major public health concern, standing as the leading cause of cancer-related deaths worldwide. Among its subtypes, small-cell lung cancer (SCLC) is characterized by aggressive and rapid growth, poor differentiation, and neuroendocrine features. Typically, SCLC is diagnosed at an advanced stage (extensive disease, ED-SCLC), with distant metastases, and is strongly associated with tobacco smoking and has a poor prognosis. Recent clinical trials, such as CASPIAN and IMpower133, have demonstrated promising outcomes with the incorporation of immune checkpoint inhibitors in first-line chemotherapy, leading to prolonged progression-free survival and overall survival in patients with ED-SCLC compared to standard chemotherapy. Other studies have emphasized the potential for future development of molecularly targeted therapies in SCLC patients, including inhibitors of IGF-1R, DLL3, BCL-2, MYC, or PARP. The molecular subdivision of SCLC based on transcriptomic and immunohistochemical analyses represents a significant advancement in both diagnostic and clinical approaches in SCLC patients. Specific molecular pathways are activated within distinct transcriptome subtypes of SCLC, offering the potential for personalized treatment strategies, such as targeted therapies and immunotherapies. Such tailored approaches hold promise for significantly improving outcomes in SCLC patients.
... p = 0.059); however, the difference was not clinically significant (median PFS 5.8 versus 5.6 months), with a trend observed in SLFN11 positive patients (HR 0.6; 80% CI: 0.36-0.97). Additionally, there was no notable advantage of OS [54]. Another PARPi, niraparib, was evaluated as a first-line maintenance therapy in Chinese patients with platinum-responsive ES-SCLC in a phase III randomized trial ZL-2306-005. ...
The genes coding for the tumor suppressors p53 and retinoblastoma (Rb) are inactivated in the vast majority of small cell lung cancer (SCLC) tumors. Data support the notion that these two deleterious genetic events represent the initial steps in the development of SCLC, making them essential for a lung epithelial cell to progress toward the acquisition of a malignant phenotype. With the loss of TP53 and RB1, their broad tumor suppressive functions are eliminated and a normal cell is able to proliferate indefinitely, escape entering into cellular senescence, and evade death, no matter the damage it has experienced. Within this setting, lung epithelial cells accumulate further oncogenic mutations and are well on their way to becoming SCLC cells. Understanding the molecular mechanisms of these genetic lesions and their effects within lung epithelial cells is of paramount importance, in order to tackle this aggressive and deadly lung cancer. The present review summarizes the current knowledge on p53 and Rb aberrations, their biological significance, and their prospective therapeutic potential, highlighting completed and ongoing clinical trials with agents that target downstream pathways.
... p = 0.059), although the difference was not clinically significant (median PFS 5.8 versus 5.6 months), with a trend in SLFN11 positive patients (HR, 0.6; 80% CI: 0.36-0.97). Moreover, there was no significant benefit in OS [31]. ...
The aim of this review is to focus on the recent advances in the molecular knowledge of small cell lung cancer (SCLC) and potential promising new treatment strategies, like targeting the DNA damage pathway, epigenetics, angiogenesis, and oncogenic drivers.
In the last few years, the addition of immunotherapy to chemotherapy has led to significant improvements in clinical outcomes in this complex neoplasia. Nevertheless, the prognosis remains dismal. Recently, numerous genomic alterations have been identified, and they may be useful to classify SCLC into different molecular subtypes (SCLC-A, SCLC-I, SCLC-Y, SCLC-P).
SCLC accounts for 10-20% of all lung cancers, most patients have an extensive disease at the diagnosis, and it is characterized by poor prognosis. Despite the progresses in the knowledge of the disease, efficacious targeted treatments are still lacking. In the near future, the molecular characterisation of SCLC will be fundamental to find more effective treatment strategies.
... Many combination therapeutics with different mechanisms have been tested with PARP inhibitors, including our study. 17,30 However, none has yet to demonstrate an OS benefit. ...
Background
Based on a high incidence of genomic alteration in the cell cycle and DNA damage and response (DDR)‐related pathways in small cell lung cancer (SCLC), the clinical efficacy of the DDR‐targeting agent olaparib (PARP inhibitor) as monotherapy and in combination with ceralasertib (ATR inhibitor) in relapsed or refractory SCLC was evaluated.
Methods
As part of a phase 2 biomarker driven umbrella study, patients with SCLC and predefined DDR gene alterations who failed to benefit from prior platinum‐based regimens were allocated to the olaparib monotherapy arm and nonbiomarker‐selected patients were allocated to the olaparib and ceralasertib combination arm.
Results
In the olaparib monotherapy arm (n = 15), the objective response rate was 6.7% (one partial response), and the disease control rate was 33.3%, including three patients with stable disease. The median progression‐free survival was 1.3 months (95% CI, 1.2–NA). In the combination arm (n = 26), the objective response rate and disease control rate were 3.8% and 42.3%, respectively, with one partial response and 10 patients with stable disease. The median progression‐free survival was 2.8 months (95% CI, 1.8–5.4). Treatment was generally well tolerated except for one fatal case of neutropenic fever in the combination arm.
Conclusions
Targeting DDR pathways with olaparib as a single agent or in combination with ceralasertib did not meet the predefined efficacy end point. However, disease stabilization was more evident in the combination arm. Further investigation of the combination of olaparib in SCLC should be performed with diverse combinations and patient selection strategies to maximize efficacy.
... 15,22,23,25,26 Other biomarkers such as SLFN11 for PARP inhibitor are also actively explored in clinical trials. 27,28 Although there is increased interest in subtypes defining therapeutic vulnerabilities, the variation in expression of these transcription factors has not currently been well-established to inform patient care. ...
Introduction
SCLC is an aggressive malignancy with poor outcome. Most patients have disease recurrence despite treatments with multiple modalities. Subtyping of SCLC has been proposed recently, and novel agents targeting specific subtypes are actively being investigated. In this study, we evaluated the plasticity of subtypes in paired pre- and post-treatment samples. The aim was to understand possible subtype evolution after chemotherapy resistance that could lead to alternate targeted therapy strategies.
Methods
A total of 68 samples from 32 patients with sufficient paired specimens were identified from 1998 to 2022. ASCL1, NEUROD1, and POU2F3 immunohistochemistry studies were performed on all cases, and subtyping by predominant expression was determined. Subtype comparison in each patient was performed, and expression analysis was performed on the basis of subtypes.
Results
Of 32 cases, 28 (88%) had the same subtype in pre- and first post-treatment specimens. Protein expression level of subtype-specific transcription factor remained stable after chemotherapy. Two of five (40%) NEUROD1-predominant SCLC switched to ASCL1-predominant phenotype after treatment. One case had a pitfall of scoring ASCL1 on specimen with marked crushing artifacts. One case revealed the challenge of proper subtyping for samples with borderline POU2F3 expression.
Conclusions
Subtype of SCLC generally remains the same after acquiring chemotherapy resistance. Plasticity was observed with rare cases switching from NEUROD1-predominant to ASC1-predominant SCLC. Resubtyping is unnecessary for the consideration of novel subtype-specific targeted agents, except cases with NEUROD1-predominant subtype.
... A phase II trial investigated the efficacy of veliparib combined and following as a maintenance therapy with carboplatin and etoposide in first-line ED-SCLC treatment. 79 One hundred and eighty-one patients were randomized 1:1:1 to receive veliparib plus chemotherapy followed by veliparib maintenance, veliparib plus chemotherapy followed by placebo, or placebo plus chemotherapy followed by placebo until unacceptable toxicity or progression, with PFS as the primary endpoint. An improvement in PFS (HR=0.67; ...
In recent years, poly (ADP-ribose) polymerase (PARP) inhibition has become a promising therapeutic option for several tumors, especially for those harboring a BRCA 1–2 mutation or a deficit in the homologous recombination repair (HRR) pathway. Nevertheless, to date, PARP inhibitors are still not largely used for thoracic malignancies neither as a single agent nor in combination with other treatments. Recently, a deeper understanding of HRR mechanisms, alongside the development of new targeted and immunotherapy agents, particularly against HRR-deficient tumors, traced the path to new treatment strategies for many tumor types including lung cancer and malignant pleural mesothelioma. The aim of this review is to sum up the current knowledge about cancer-DNA damage response pathways inhibition and to update the status of recent clinical trials investigating the use of PARP inhibitors, either as monotherapy or in combination with other agents for the treatment of thoracic malignancies. We will also briefly discuss available evidence on Poly(ADP-Ribose) Glycohydrolase (PARG) inhibitors, a novel promising therapeutic option in oncology.
... in multiple cancers. 46,47 Intriguingly, several studies also reported that the DNA methylation status of SLFN11 in plasma cell-free DNA and SLFN11-positive circulating tumor cells could predict platinum resistance in ovarian cancer and small cell lung cancer, respectively. 48,49 Hence, SLFN11 may serve as a peripheral blood biomarker for the prediction and dynamic monitoring of the ICI response in patients with advanced HCC in a minimally invasive manner, which raises great possibilities for its clinical translation. ...
Background & aims:
The therapeutic effect of immune checkpoint inhibitors (ICIs) is poor in hepatocellular carcinoma (HCC) and varies greatly among individuals. Schlafen (SLFN) family members have important functions in immunity and oncology, but their roles in cancer immunobiology remain unclear. Herein, we aimed to investigate the role of the SLFN family in immune responses against HCC.
Methods:
Transcriptome analysis was performed in human HCC tissues with or without response to ICIs. A humanized orthotopic HCC mouse model and a coculture system were constructed, and cytometry by time-of-flight (CyTOF) technology was used to explore the function and mechanism of SLFN11 in the immune context of HCC.
Results:
SLFN11 was significantly upregulated in tumors that responded to ICIs. Tumor-specific SLFN11 deficiency increased the infiltration of immunosuppressive macrophages and aggravated HCC progression. HCC cells with SLFN11 knockdown promoted macrophage migration and M2-like polarization in a CCL2-dependent manner, which in turn elevated their own PD-L1 expression by activating the NF-κB pathway. Mechanistically, SLFN11 suppressed the Notch pathway and CCL2 transcription by binding competitively with TRIM21 to the RRM2 domain of RBM10, thereby inhibiting TRIM21-mediated RBM10 degradation to stabilize RBM10 and promote NUMB exon 9 skipping. Pharmacological antagonism of CCR2 potentiated the antitumor effect of anti-PD-1 in humanized mice bearing SLFN11 knockdown tumors. ICIs were more effective in HCC patients with high serum SLFN11 levels.
Conclusions:
SLFN11 serves as a critical regulator of microenvironmental immune properties and an effective predictive biomarker of ICIs response in HCC. Blockade of CCL2/CCR2 signaling sensitized SLFN11low HCC patients to ICI treatment.
... However, veliparib has been essentially overlooked as a leading compound for PARP PET tracer development, despite its more desirable characteristics for brain PET imaging, i.e., high brain exposure, fast brain kinetics and less P-glycoprotein (P-gp) efflux from the brain [20]. As a therapeutic drug, veliparib has been investigated extensively to treat non-small cell lung cancer, BRCA-mutated advanced breast cancer and ovarian cancer [21][22][23][24]. In fact, some of the current PARP PET tracers have been investigated as PET imaging agents in gliomas but suffer from limited brain penetration and liability to efflux by transporter proteins [25,26]. ...
Purpose
Currently, there are multiple active clinical trials involving poly(ADP-ribose) polymerase (PARP) inhibitors in the treatment of glioblastoma. The noninvasive quantification of baseline PARP expression using positron emission tomography (PET) may provide prognostic information and lead to more precise treatment. Due to the lack of brain-penetrant PARP imaging agents, the reliable and accurate in vivo quantification of PARP in the brain remains elusive. Herein, we report the synthesis of a brain-penetrant PARP PET tracer, (R)-2-(2-methyl-1-(methyl-¹¹C)pyrrolidin-2-yl)-1H-benzo[d]imidazole-4-carboxamide ([¹¹C]PyBic), and its preclinical evaluations in a syngeneic RG2 rat glioblastoma model and healthy nonhuman primates.
Methods
We synthesized [¹¹C]PyBic using veliparib as the labeling precursor, performed dynamic PET scans on RG2 tumor-bearing rats and calculated the distribution volume ratio (DVR) using simplified reference region method 2 (SRTM2) with the contralateral nontumor brain region as the reference region. We performed biodistribution studies, western blot, and immunostaining studies to validate the in vivo PET quantification results. We characterized the brain kinetics and binding specificity of [¹¹C]PyBic in nonhuman primates on FOCUS220 scanner and calculated the volume of distribution (VT), nondisplaceable volume of distribution (VND), and nondisplaceable binding potential (BPND) in selected brain regions.
Results
[¹¹C]PyBic was synthesized efficiently in one step, with greater than 97% radiochemical and chemical purity and molar activity of 148 ± 85 MBq/nmol (n = 6). [¹¹C]PyBic demonstrated PARP-specific binding in RG2 tumors, with 74% of tracer binding in tumors blocked by preinjected veliparib (i.v., 5 mg/kg). The in vivo PET imaging results were corroborated by ex vivo biodistribution, PARP1 immunohistochemistry and immunoblotting data. Furthermore, brain penetration of [¹¹C]PyBic was confirmed by quantitative monkey brain PET, which showed high specific uptake (BPND > 3) and low nonspecific uptake (VND < 3 mL/cm³) in the monkey brain.
Conclusion
[¹¹C]PyBic is the first brain-penetrant PARP PET tracer validated in a rat glioblastoma model and healthy nonhuman primates. The brain kinetics of [¹¹C]PyBic are suitable for noninvasive quantification of available PARP binding in the brain, which posits [¹¹C]PyBic to have broad applications in oncology and neuroimaging.
... However, veliparib has been essentially overlooked as a leading compound for PARP PET tracer development, despite its more desirable characteristics for brain PET imaging, i.e., high brain exposure, fast brain kinetics and less P-glycoprotein (P-gp) e ux from the brain 20 . As a therapeutic drug, veliparib has been investigated extensively to treat non-small cell lung cancer, BRCA-mutated advanced breast cancer and ovarian cancer 21 22 23 24 . In fact, some of the current PARP PET tracers have been investigated as PET imaging agents in gliomas but suffer from limited brain penetration and liability to e ux by transporter proteins 25,26 . ...
Purpose Currently, there are multiple active clinical trials involving poly(ADP-ribose) polymerase (PARP) inhibitors in the treatment of glioblastoma. The noninvasive quantification of baseline PARP expression using positron emission tomography (PET) may provide prognostic information and lead to more precise treatment. Due to the lack of brain-penetrant PARP imaging agents, the reliable and accurate in vivo quantification of PARP in the brain remains elusive. Herein, we report the synthesis of a brain-penetrant PARP PET tracer, (R)-2-(2-methyl-1-(methyl-¹¹C)pyrrolidin-2-yl)-1H-benzo[d]imidazole-4-carboxamide ([¹¹C]PyBic), and its preclinical evaluations in a syngeneic RG2 rat glioblastoma model and healthy nonhuman primates.
Methods We synthesized [¹¹C]PyBic using veliparib as the labeling precursor, performed dynamic PET scans on RG2 tumor-bearing rats and calculated the distribution volume ratio (DVR) using simplified reference region method 2 (SRTM2) with the contralateral nontumor brain region as the reference region. We performed biodistribution studies, western blot, and immunostaining studies to validate the in vivo PET quantification results. We characterized the brain kinetics and binding specificity of [¹¹C]PyBic in nonhuman primates on FOCUS220 scanner and calculated the volume of distribution (VT), nondisplaceable volume of distribution (VND), and nondisplaceable binding potential (BPND) in selected brain regions.
Results [¹¹C]PyBic was synthesized efficiently in one step, with greater than 97% radiochemical and chemical purity and molar activity of 148 ± 85 MBq/nmol (n = 6). [¹¹C]PyBic demonstrated PARP-specific binding in RG2 tumors, with 74% of tracer binding in tumors blocked by preinjected veliparib (i.v., 5 mg/kg). The in vivo PET imaging results were corroborated by ex vivo biodistribution, PARP1 immunohistochemistry and immunoblotting data. Furthermore, brain penetration of [¹¹C]PyBic was confirmed by quantitative monkey brain PET, which showed high specific uptake (BPND > 3) and low nonspecific uptake (VND < 3 mL/cm³) in the monkey brain.
Conclusion [¹¹C]PyBic is the first brain-penetrant PARP PET tracer validated in a rat glioblastoma model and healthy nonhuman primates. The brain kinetics of [¹¹C]PyBic are suitable for noninvasive quantification of available PARP binding in the brain, which posits [¹¹C]PyBic to have broad applications in oncology and neuroimaging.
... PARPi niraparib as monotherapy modestly delays disease progression and prolongs survival with an acceptable tolerability profile in patients with ES-SCLC [17]. PARPi combined with other inhibitors has been exploited in the clinic and showed some improvement in SCLC patients [18,19]. However, PARPi is not currently part of the treatment armamentarium for SCLC. ...
Small-cell lung cancer (SCLC) is an aggressive high-grade neuroendocrine carcinoma of the lung associated with early metastasis and an exceptionally poor prognosis. Little progress has been made in developing efficacious targeted therapy for this recalcitrant disease. Herein, we showed that H3.3, encoded by two genes (H3F3A and H3F3B), was prominently overexpressed in SCLC. Darinaparsin (ZIO-101), a derivative of arsenic trioxide, dose- and time-dependently inhibited the viability of SCLC cells in an H3.3-dependent manner. More importantly, ZIO-101 treatment resulted in substantial accumulation of H3.3 and PARP1 besides induction of G2/M cell cycle arrest and apoptosis in SCLC cells. Through integrative analysis of the RNA-seq data from Cancer Cell Line Encyclopedia dataset, JNCI and Genomics of Drug Sensitivity in Cancer 2 datasets, we found that H3F3A expression was negatively correlated with the IC50 values of PARP inhibitors (PARPi). Furthermore, co-targeting H3.3 and PARP1 by ZIO-101 and BMN673/olaparib achieved synergistic growth inhibition against SCLC in vitro and in vivo. In conclusion, it is feasible to target H3.3 by ZIO-101 to potentiate the response rate of PARPi in SCLC patients.
... In a phase III, randomized, placebo-controlled BROCADE3 trial, the addition of veliparib to carboplatin and paclitaxel improved progression-free survival (PFS) in patients with advanced HER2-negative germline BRCA1/2-mutated breast cancer (58). The combination of veliparib plus carboplatin and etoposide demonstrated improved PFS as first-line treatment in patients with extensive-stage small cell lung cancer (59). Promising antitumor activity was also observed in patients with metastatic or advanced non-small cell lung cancer receiving quadruple therapy with veliparib, nivolumab, carboplatin and paclitaxel (60). ...
Germ cell tumors (GCTs) usually represent efficiently curable neoplasms due to their chemosensitivity to platinum-based therapeutic regimen. However, some patients develop therapeutic resistance and succumb to their disease. Novel therapeutic approaches are therefore needed for these patients. It has previously been demonstrated that poly (ADP-ribose) polymerase (PARP) expression is upregulated in GCTs compared with normal testis tissue. Therefore, PARP expression was analyzed in GCT cell lines and xenografts and it was examined whether its inhibition by veliparib can reverse cisplatin-resistance. Its expression was analyzed in sensitive and cisplatin-resistant variants (referred to as CisR throughout the manuscript) GCT cell lines and xenografts using quantitative PCR, western blotting and immunohistochemistry. The present study investigated whether the combination of cisplatin with the PARP inhibitor veliparib increased the cytotoxic effect of cisplatin in vitro using a luminescent viability assay and an immunodeficient mouse model in vivo. PARP expression was observed in all tested cell lines, with the highest expression in embryonal carcinoma (EC) cell lines and xenografts. Low or no expression was detected in the JEG-3 choriocarcinoma cell line pairs and xenografts. The combination of veliparib and cisplatin or carboplatin was examined in the cisplatin-resistant NTERA-2 CisR and NCCIT CisR EC cell lines and synergistic effects were observed in NTERA-2 CisR cells. However, in vivo analysis did not confirm this synergy. The present data indicated PARP expression in GCT cell lines and xenografts. However, veliparib failed to increase the cytotoxicity of platinum-based drugs. Therefore, further research is warranted to effectively inhibit PARP using different PARP inhibitors or other drug combinations.
... It was reported that veliparib plus platinum chemotherapy followed by veliparib maintenance therapy as a first-line treatment displayed improved progression-free survival (PFS) for extensive-stage small-cell lung cancer (ES-SCLC) with an acceptable safety profile. 28 Another phase 3 study showed that niraparib modestly improved PFS in patients with platinum-responsive ES-SCLC. 29 According to these studies, HRR gene mutation status has the potential to be a biomarker for identifying SCLC patients who might respond to PARP inhibitors. ...
Background:
Homologous recombination deficiency (HRD) is a well-known biomarker which could predict poly-ADP ribose polymerase 1 (PARP) inhibitor and platinum drug response. As an aggressive cancer, small-cell lung cancer (SCLC) is sensitive to platinum drugs, but relapse occurs rapidly. Herein, we aim to illustrate the genomic alteration patterns of homologous recombination repair (HRR)-related genes in a Chinese SCLC cohort and further analyze the relationship among HRR gene mutations and known biomarkers of immune checkpoint inhibitor (ICI) response, including tumor mutation burden (TMB) and programmed cell death-ligand 1 (PD-L1) expression.
Methods:
Next-generation sequencing (NGS)-based target capture sequencing of 543 cancer-related genes was performed to analyze the genomic profiles of 133 Chinese SCLC patients, and TMB was calculated. PD-L1 expression was evaluated in 90 out of 133 patients using the SP142 PD-L1 immunohistochemistry assay.
Results:
Among the 133 patients with SCLC, 47 (35.3%) had HRR gene mutations. ATM (8.3%) was the most frequently mutated HRR gene in the cohort, followed by NBN (4.5%). Pathogenic somatic and germline mutations of HRR genes were identified in 11 (23.4%) and 4 (8.5%) patients, respectively. HRR gene mutations cooccurred with KMT2D gene mutations. There were several differences in genomic alterations between patients with HRR gene mutations (HRR-Mut) and without HRR mutations (HRR-WT). The results revealed that TP53 and RB1 were commonly mutated genes in both groups. Mutations in the KMT2D gene and genes in the RTK-RAS pathway occurred more frequently in the HRR-Mut group. Furthermore, we found that mutations in HRR genes were associated with high TMB (Wilcoxon, p = 0.048), but there was no correlation of HRR gene mutation status with PD-L1 expression.
Conclusions:
We exhaustively describe the genomic alteration profile of Chinese SCLC patients and provide further evidence that HRR gene mutations are prevalent in SCLC patients.
... This observation has promoted several clinical studies aiming to evaluate the capacity of a PARP inhibitor Veliparib, to improve the clinical benefit deriving from the standard chemotherapy with platinum and etoposide. These studies have shown that Veliparib plus platinum chemotherapy was able to improve PFS as firstline treatment for SCLC; however, this improvement in PFS was not associated with a concomitant benefit in OS [79,[81][82][83]. In one of these studies, SLFN11 positivity showed a trend toward improved response in the group treated with Veliparib compared to control [82]. ...
Small-cell lung cancer (SCLC) is a high-grade neuroendocrine carcinoma, corresponding to about 15% of lung cancers, occurring predominantly in smokers and associated with a very poor prognosis. Key genetic alterations very frequently observed in SCLC are represented by the loss of TP53 and RB1, due to mutational events or deletions; frequent amplification or overexpression of MYC family genes (MYC, MYCL and MYCN); frequent genetic alterations by mutation/deletion of KMT2D, RB family members p107 (RBL1) and p130 (RBL2), PTEN, NOTCH receptors and CREBBP. The profile of expression of specific transcription factors allowed to differentiate four subtypes of SCLC defined according to levels of ASCL1 (SCLC-A), NEUROD1 (SCLC-N), POUF23 (SCLC-P) or YAP1 (SCLC-Y). A recent study identified the subgroup SCLC-I, characterized by the expression of inflammatory/immune-related genes. Recent studies have characterized at molecular level other lung neuroendocrine tumors, including large cell neuroendocrine cancers (LCNECs) and lung carcinoids. These molecular studies have identified some therapeutic vulnerabilities that can be targeted using specific drugs and some promising biomarkers that can predict the response to this treatment. Furthermore, the introduction of immunotherapy (immune checkpoint blockade) into standard first-line treatment has led to a significant clinical benefit in a limited subset of patients.
... [47] A randomized Phase 2 study of veliparib plus EP in treatment naïve SCLC patients demonstrated a slight improvement in PFS from 5.6 to 5.8 months without a corresponding benefit in overall survival. [48] More encouraging was the identification of Schlafen 11 (SLFN11), an RNA/DNA helicase that serves as a potential predictive biomarker for sensitivity to PARP inhibition, since SLFN11 expression, which is high in SCLC, decreases significantly after treatment with veliparib. [49] c) Temozolomide Temozolomide (TMZ) is an oral alkylating agent [50], previously shown to have single agent activity in SCLC, which is known to synergize with PARP inhibitors that prevent repair of temozolomideinduced DNA damage. ...
For close to 40 years small-cell lung cancer (SCLC) was adrift, as listless, and as idle as a painted ship on a painted ocean, with nary a breeze to blow in the direction of clinical progress or change. The preferred decades-old first line regimen was etoposide-platinum, to which ≥50% of patients respond, followed by decades-old, tired topotecan in second line for platinum sensitive patients, full stop, because there were no approved therapeutic options (nor generally any compelling experimental ones) in third line or beyond. In 2012 SCLC was designated by the U.S. Congress as a “recalcitrant” tumor type and for good reason: because most patients relapse, after the generally favorable response in first line, respond poorly, if at all to subsequent therapies, and rarely survive beyond 1 year.
A significant sea change occurred in 2018 with the approval of nivolumab followed by pembrolizumab and atezolizumab in 2019, durvalumab in 2020, accelerated approval for lurbinectedin in 2020 and trilaciclib in 2021 for myelosuppression. In 2021, the US indications for nivolumab and pembrolizumab were withdrawn. Suddenly, a tumor type, whose name was virtually synonymous with stalled progress and movement, and which was much less well studied and funded than its more prevalent cousin, non-small cell lung cancer (NSCLC), finds itself in the eye of the storm, that is, at the epicenter of an intense flurry and ferment of activity, not all of it positive. This review surveys approved drugs and select up-and-coming ones in development for extensive stage SCLC.
... Based on promising findings from preclinical studies, the predictive role of SLFN11 is being assessed across different cancer types in a clinical setting. There is increasing evidence that patients with SLFN11-positive solid tumors, such as small cell lung cancer or Ewing sarcoma, respond better to DDA and/or PARPi [28,58,59]. ...
Simple Summary
Anticancer agents causing DNA damage are widely used in the treatment of ovarian cancer; however, predictive biomarkers capable of optimizing the selection of patients with the best likelihood of a good response have not been defined yet. The newly discovered protein Schlafen 11 was identified to have a casual association with responses to a wide range of DNA-damaging agents, including platinum compounds and PARP inhibitors. We review the current state of knowledge regarding the role of Schlafen 11 as a biomarker in ovarian cancer and its potential to identify patients not responding to the systemic treatment.
Abstract
Platinum-based chemotherapy has been the cornerstone of systemic treatment in ovarian cancer. Since no validated molecular predictive markers have been identified yet, the response to platinum-based chemotherapy has been evaluated clinically, based on platinum-free interval. The new promising marker Schlafen 11 seems to correlate with sensitivity or resistance to DNA-damaging agents, including platinum compounds or PARP inhibitors in various types of cancer. We provide background information about the function of Schlafen 11, its evaluation in tumor tissue, and its prevalence in ovarian cancer. We discuss the current evidence of the correlation of Schlafen 11 expression in ovarian cancer with treatment outcomes and the potential use of Schlafen 11 as the key predictive and prognostic marker that could help to better stratify ovarian cancer patients treated with platinum-based chemotherapy or PARP inhibitors. We also provide perspectives on future directions in the research on this promising marker.
... In the phase III VELIA trial, ovarian cancer patients treated with carboplatin, paclitaxel and veliparib experienced higher rates of any grade and G3/4 neutropenia, anemia and thrombocytopenia compared with those receiving chemotherapy only [33]. Similar results emerged in a phase II randomized trial comparing veliparib plus carboplatin and etoposide to carboplatin and etoposide alone in small cell lung cancer patients [81]. Conversely, PARP inhibitors did not significantly modify the safety profile of standard chemotherapeutic regimens in several randomized trials across different tumor types, including breast, gastric, pancreatic and lung cancer [80,[82][83][84][85]. ...
Simple Summary
DNA damage induces genome instability, which may elicit cancer development. Defects in the DNA repair machinery further enhance cancer predisposition, but can also be exploited as a therapeutic target. Indeed, targeted agents against specific components of DNA repair, such as PARP inhibitors, are employed in various tumor types, while others, such as ATR, CHK1 or WEE1 inhibitors, are in clinical development. Even though these molecules have proven to be effective in different settings, they display several on- and off-target toxicities, shared by the whole pharmacological class or are drug specific. Among these effects, hematological and gastrointestinal toxicities are the most common, while others are less frequent but potentially life-threatening (e.g., myelodysplastic syndromes). Particular caution is needed in the case of combinatorial therapeutic approaches, which are currently being developed in clinical trials. In any case, it is necessary to recognize and properly manage adverse events of these drugs. This review provides a comprehensive overview on the safety profile of DDR-targeting agents, including indications for their management in clinical practice.
Abstract
Targeting the inherent vulnerability of cancer cells with an impaired DNA Damage Repair (DDR) machinery, Poly-ADP-Ribose-Polymerase (PARP) inhibitors have yielded significant results in several tumor types, eventually entering clinical practice for the treatment of ovarian, breast, pancreatic and prostate cancer. More recently, inhibitors of other key components of DNA repair, such as ATR, CHK1 and WEE1, have been developed and are currently under investigation in clinical trials. The inhibition of DDR inevitably induces on-target and off-target adverse events. Hematological and gastrointestinal toxicities as well as fatigue are common with all DDR-targeting agents, while other adverse events are drug specific, such as hypertension with niraparib and transaminase elevation with rucaparib. Cases of pneumonitis and secondary hematological malignancies have been reported with PARP inhibitors and, despite being overly rare, they deserve particular attention due to their severity. Safety also represents a crucial issue for the development of combination regimens incorporating DDR-targeting agents with other treatments, such as chemotherapy, anti-angiogenics or immunotherapy. As such, overlapping and cumulative toxicities should be considered, especially when more than two classes of drugs are combined. Here, we review the safety profile of DDR-targeting agents when used as single agents or in combination and we provide principles of toxicity management.
Background
Poly (ADP-Ribose) Polymerase (PARP) inhibitors represent a novel class of drugs that hinder DNA repair mechanisms in tumor cells, leading to cell death. This systematic review aims to evaluate the effectiveness, safety, and potential adverse effects of PARP inhibitors (PARPi) in the management of patients with advanced lung cancer.
Materials and Methods
We conducted a comprehensive search for relevant studies in PubMed, Embase, Cochrane, and ClinicalTrials.gov . We extracted primary and secondary outcome measures, including progression-free survival (PFS), overall survival (OS), and adverse events (AEs), from the identified literature for subsequent meta-analysis and systematic review.
Results
This study encompassed twelve randomized controlled trials, involving 3,132 patients with advanced lung cancer. In comparison to non-PARPi treatments, the administration of PARPi significantly extended OS (hazard ratio (HR) = 0.90, 95% CI = 0.83–0.97, p = 0.006). However, the difference in PFS did not reach statistical significance.
Conclusion
In summary, therapies incorporating PARPi provide a degree of benefit by extending OS in patients with advanced lung cancer. Nonetheless, further trials are necessary to furnish additional evidence regarding the efficacy and safety of PARPi in the treatment of lung cancer.
Systematic Review Registration
https://www.crd.york.ac.uk/PROSPERO/ , identifier number: CRD42023424673.
Small cell lung cancer (SCLC) is an uncommon, aggressive high-grade neuroendocrine carcinoma, associated with tobacco use. It is a highly chemosensitive disease that initially responds quickly to systemic therapy, although patients with SCLC tend to develop relapse. Although the landscape of SCLC treatment has remained stagnant for many decades, the field has seen notable advances in the past few years, including the use of immunotherapy, the development of further lines of systemic therapy, the refinement of thoracic and intracranial radiotherapy, and—most recently—the promise of more targeted therapies. Patients with SCLC also must face unique psychosocial burdens in their experience with their cancer, distinct from patients with other lung cancer. In this article, we review the latest literature and future directions in the management and investigation of SCLC, as well as the critical decisions that providers and patients must navigate in the current landscape. We also present the perspectives of several patients with SCLC in conjunction with this summary, to spotlight their individual journeys in the context of this challenging disease.
Small-cell lung cancer (SCLC) is a biologically aggressive subtype of lung cancer, a lethal disease characterized by rapid tumor growth, early relapse, a strong tendency for early widespread metastasis, and high genomic instability, making it a formidable foe in modern oncology practice. While the management of non-SCLC has been revolutionized in the era of immunotherapy, progress in SCLC has been more muted. Recent randomized phase III clinical trials have combined programmed death ligand-1 inhibitors to a chemotherapy backbone and demonstrated improved survival; however, the absolute benefit observed is short months. There is an undeniable urgent need for better responses, better agents, novel therapeutic approaches, and more rational, biomarker-driven clinical trials in SCLC. In this review, we discuss the rationale and current understanding of the biology of SCLC in the modern era of immunotherapy, discuss recent advances in front-line immunotherapeutic approaches that have changed clinical practice globally, provide an overview of some of the challenges and limitations that have staggered immune checkpoint blockade in SCLC, and explore some of the novel immunotherapeutic approaches currently being investigated.
Background
Arterial hypertension has been recently reported from randomized controlled trials (RCTs) assessing poly (ADP‐ribose) polymerase inhibitor (PARPi).
Objective
In a context of increasing use of PARPi, it is crucial to properly assess risk and incidence of this adverse event for clinical practice.
Methods
We performed a systematic review and meta‐analysis in MEDLINE, Cochrane CENTRAL and ClinicalTrials.gov up to January 4, 2023 with an ongoing surveillance up to June 7, 2023. RCTs comparing PARPi to placebo in adult patients with solid tumors were included if hypertension was reported. The primary outcome was the summary risk ratio (RR, with 95% CIs) of any hypertension of PARPi class in placebo RCTs. Secondary outcomes were the summary risk and incidence of hypertension of each individual PARPi. To provide clinical features of PARPi‐associated hypertension, we independently queried the WHO's pharmacovigilance database, up to September 1, 2022.
Results
In total, 41 placebo RCTs ( n = 15 264 adult patients) were included. PARPi class was not associated with an increased risk of hypertension compared with placebo. In individual analyses, the risk of hypertension was lower with olaparib than placebo (RR 0.77 [95% CI: 0.68–0.86], P < 0.01; I ² = 19%, χ ² P = 0.26). Niraparib monotherapy increased the risk of any (RR 2.84 [95% CI: 1.76–4.57], P < 0.01; I ² = 66%, χ ² P = 0.01) hypertension with a summary incidence of 19.87% (95% CI: 15.23–25.50). In real‐life setting, niraparib‐associated hypertension occurs within 20 days and was serious in 66%. Co‐prescription of at least one antihypertensive or therapy‐induced hypertension was reported in 20.5% or 14.4% of cases, respectively.
Conclusions
In a context of extensive assessment of niraparib in combination, these data reinforce the need of a close monitoring of this adverse event to preserve its clinical benefit on patients' survival.
Better understanding of molecular drivers and dysregulated pathways has furthered the concept of precision oncology and rational drug development. The role of DNA damage response (DDR) pathways has been extensively studied in carcinogenesis and as potential therapeutic targets to improve response to chemotherapy or overcome resistance. Treatment with small molecule inhibitors of PARP has resulted in clinical response and conferred survival benefit to patients with ovarian cancer, BRCA-mutant breast cancer, HRD-deficient prostate cancer and BRCA-mutant pancreatic cancer, leading to US Food and Drug Administration (FDA) approvals. However, the observed clinical benefit with single agent PARP inhibitors is limited to few tumor types within the relevant genetic context. Since DDR pathways are essential for repair of damage caused by cytotoxic agents, PARP inhibitors have been evaluated in combination with various chemotherapeutic agents to broaden the therapeutic application of this class of drugs. In this chapter, we discuss the combination of PARP inhibitors with different chemotherapeutics agents, clinical experience to date, lessons learnt, and future directions for this approach.
Objective
Lung cancer, originating from bronchial mucosa or lung glands, poses significant health risks due to its rising incidence and mortality. This study aimed to assess the efficacy and safety of Veliparib combined with chemotherapy versus pharmacotherapy alone for lung cancer treatment, guiding clinical approaches for this severe disease.
Methods
Comprehensive searches in PubMed, EMBASE, Cochrane, and Web of Science were conducted to identify randomized controlled trials (RCTs) comparing Veliparib combined with standard chemotherapy to chemotherapy alone in lung cancer treatment, up until December 28, 2022. Two reviewers meticulously selected literature based on inclusion and exclusion criteria. The Cochrane tool was used to assess the bias risk of the included studies, and meta-analysis was performed using Stata 15.0.
Results
Five RCTs (1,010 participants) were included. The analysis results showed that only Veliparib combinedwith chemotherapy prolonged the progression-free survival (PFS) in small cell lung cancer (SCLC) patients [HR = 0.72, 95% CI = (0.57, 0.90)]. No significant differences were observed in overall survival (OS) and objective response rate (ORR). Veliparib and combined chemotherapy caused some side effects in patients with lung cancer, including leukopenia [RR = 2.12, 95% CI = (1.27, 3.55)], neutropenia [RR = 1.51, 95% CI = (1.01, 2.26)], anemia [RR = 1.71, 95% CI = (1.07, 3.07)], and thrombocytopenia [RR = 3.33, 95% CI = (1.19, 9.30)]. For non-small cell lung cancer (NSCLC) patients, there were no statistically significant differences in PFS, OS, or ORR between the experimental and control groups [HR = 0.97, 95% CI = (0.75, 1.27)].
Conclusion
The strategy of combining Veliparib with chemotherapy may, to some extent, prolong the PFS in lung cancer patients. However, this benefit is not observed in OS or ORR. Additionally, there are evident adverse reactions. Due to a limited number of the included studies, additional extensive multicenter RCTs are required to validate these results. PROSPERO registration number: CRD42023411510.
PURPOSE
To provide evidence-based recommendations to practicing clinicians on the management of patients with small-cell lung cancer.
METHODS
An Expert Panel of medical oncology, thoracic surgery, radiation oncology, pulmonary, community oncology, research methodology, and advocacy experts were convened to conduct a literature search, which included systematic reviews, meta-analyses, and randomized controlled trials published from 1990 through 2022. Outcomes of interest included response rates, overall survival, disease-free survival or recurrence-free survival, and quality of life. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.
RESULTS
The literature search identified 95 relevant studies to inform the evidence base for this guideline.
RECOMMENDATIONS
Evidence-based recommendations were developed to address systemic therapy options, timing of therapy, treatment in patients who are older or with poor performance status, role of biomarkers, and use of myeloid-supporting agents in patients with small-cell lung cancer. Additional information is available at www.asco.org/thoracic-cancer-guidelines .
The anti-cancer efficacy of anti-malignancy therapies is related to DNA damage. However, DNA damage-response mechanisms can repair DNA damage, failing anti-tumor therapy. The resistance to chemotherapy, radiotherapy, and immunotherapy remains a clinical challenge. Thus, new strategies to overcome these therapeutic resistance mechanisms are needed. DNA damage repair inhibitors (DDRis) continue to be investigated, with polyadenosine diphosphate ribose polymerase inhibitors being the most studied inhibitors. Evidence of their clinical benefits and therapeutic potential in preclinical studies is growing. In addition to their potential as a monotherapy, DDRis may play an important synergistic role with other anti-cancer therapies or in reversing acquired treatment resistance. Here we review the impact of DDRis on solid tumors and the potential value of combinations of different treatment modalities with DDRis for solid tumors.
Background:
The efficacy and toxicity profiles for extensive-stage small cell lung cancer (ES-SCLC) are unclear. We aimed to address this gap through a Bayesian network meta-analysis.
Methods:
We performed network analysis from randomized controlled trials comparing these treatments: PD-(L)1 inhibitor, CTLA-4 inhibitor, CXCR inhibitor, PARP inhibitor, CDK inhibitor, chemotherapy, and their combinations. Pooled estimations of progression-free survival, overall survival, objective response rate, and toxicity (systematic and specific) were conducted within the Bayesian framework.
Results:
Twenty-five trials involving 9 strategies were included. In terms of progression-free survival and overall survival, PD-(L)1 inhibitor combined with cisplatin/carboplatin (P) and etoposide (E) shown the acknowledged superiority than other treatments. The addition of CTLA-4 inhibitor (ipilimumab) to EP had the highest response rate among these regimens, and the combination of chemotherapy (irinotecan) and cisplatin/carboplatin had the greatest probability of performing considerable systematic security. The secondary endpoint was specific adverse events, including vomiting, fatigue, thrombocytopenia, constipation, and decreased appetite; hence we depicted the specific toxicity profile of each regimen. In addition, we identified the differences between PD-1 inhibitors and PD-L1 inhibitors in prolonging overall survival time for the central nervous system (CNS)/liver metastases patients.
Conclusions:
EP combined with PD-(L)1 inhibitor followed by CTLA-4 inhibitors or anti-angiogenesis was the considerable treatment with considerable efficacy and safety for ES-SCLC. Each treatment has a unique specific toxicity profile, which needs more attention.
Background:
Poly(ADP-ribose) polymerase (PARP) inhibitors (PARPi) provided significant antitumor activity in various tumors, mainly carrying deleterious mutations of BRCA1/BRCA2 genes. Only few data are available regarding the cardiac and vascular safety profile of this drug class. We carried out a meta-analysis for assessing the incidence and relative risk (RR) of major adverse cardiovascular events (MACEs), hypertension, and thromboembolic events in patients with solid tumors treated with PARPi-based therapy.
Methods:
Prospective studies were identified by searching the Medline/PubMed, Cochrane Library, and ASCO Meeting abstracts. Data extraction was conducted according to the Preferred Reporting Items for Systematic review and Meta-Analyses (PRISMA) statement. Combined odds ratios (ORs), RRs, and 95% confidence intervals (CIs) were calculated using fixed- or random-effects methods, depending on studies heterogeneity. RevMan software for meta-analysis (v.5.2.3) was used to carry out statistical analyses.
Results:
Thirty-two studies were selected for the final analysis. The incidence of PARPi-related MACEs of any and high grade was 5.0% and 0.9%, respectively, compared with 3.6% and 0.9% in the control arms, corresponding to a significant increased risk of MACEs of any grade (Peto OR 1.62; P = 0.0009) but not of high grade (P = 0.49). The incidence of hypertension of any grade and high grade was 17.5% and 6.0% with PARPi, respectively, compared with 12.6% and 4.4% in the controls. Treatment with PARPi significantly increased the risk of hypertension of any grade (random-effects, RR = 1.53; P = 0.03) but not of high grade (random-effects, RR = 1.47; P = 0.09) compared with controls. Finally, PARPi-based therapies significantly increased the risk of thromboembolic events of any grade (Peto OR = 1.49, P = 0.004) and not of high grade (Peto OR = 1.31; P = 0.13) compared with controls.
Conclusions:
PARPi-based therapy is associated with a significantly increased risk of MACEs, hypertension, and thromboembolic events of any grade compared with controls. The lack of a significant increased risk of high-grade events together with the absolute low incidence of these adverse events led not to consider routine cardiovascular monitoring as recommended in asymptomatic patients.
Targeted therapy and immunotherapy have revolutionized cancer treatment. However, the ability of cancer to evade the immune system remains a major barrier for effective treatment. Related to this, several targeted DNA-damage response inhibitors (DDRis) are being tested in the clinic and have been shown to potentiate anti-tumor immune responses. Seminal studies have shown that these agents are highly effective in a pan-cancer class of tumors with genetic defects in key DNA repair genes such as BRCA1/2, BRCA-related genes, ataxia telangiectasia mutated (ATM), and others. Here, we review the molecular consequences of targeted DDR inhibition, from tumor cell death to increased engagement of the anti-tumor immune response. Additionally, we discuss mechanistic and clinical rationale for pairing targeted DDRis with immunotherapy for enhanced tumor control. We also review biomarkers for patient selection and promising new immunotherapy approaches poised to form the foundation of next-generation DDRi and immunotherapy combinations.
For many years the standard of care for small cell lung cancer (SCLC) has remained unchanged. Despite decades of active research, current treatment options are limited and the prognosis of patients with extended disease (ED) SCLC remains poor. The introduction of immune checkpoint inhibitors (ICIs) represents an exception and the only recent approval for ED-SCLC. However, the magnitude of benefit obtained with immunotherapy in SCLC is much more modest than that observed in other malignancies. Different pro-immunogenic or immunosuppressive features within the tumor microenvironment of SCLC may either modulate the sensitivity to immunotherapy or conversely dampen the efficacy of ICIs. Beside immunotherapy, a deeper understanding of the molecular biology of SCLC has led to the identification of new therapeutic targets for this lethal malignancy. Recent epigenetic and gene expression studies have resulted into a new molecular classification of four distinct subtypes of SCLC, defined by the relative expression of key transcription regulators and each characterized by specific therapeutic vulnerabilities. This review discusses the rationale for immunotherapy in SCLC and summarizes the main ICIs-trials in this tumor. We provide also an overview of new potential therapeutic opportunities and their integration with the new molecular classification of SCLC.
Extensive‐stage small‐cell lung cancer (ES‐SCLC) is regarded as a refractory carcinoma associated with extremely rapid disease progression. After more than three decades without clinical advances, research on immune checkpoint inhibitors (ICIs) combined with platinum‐based chemotherapy has led to the first treatment breakthrough, establishing a new standard for the first‐line treatment of ES‐SCLC. Further studies have extensively evaluated small‐molecule antiangiogenic drugs, PARP inhibitors, as well as lurbinectedin in SCLC and have demonstrated some benefit, although no breakthroughs have been made. In addition, newer therapeutic strategies with targeted agents, novel chemotherapeutics and immunotherapies are evolving as they are being actively explored and hold promise for patients with this disease. Notably, the preliminary identification of SCLC molecular subtypes driven by the expression of dominant transcription factors with RNA sequencing profiles has made it possible to identify molecularly tailored therapeutic approaches, which increases the potential for individualized precision treatment of SCLC. In this review, we summarize recent research advances in ES‐SCLC, outline the current management of this disease and reflect on directions for future development.
Since the concept, DNA damage repair has been stated as a natural biological event, and research has increasingly revealed its strong association to tumors, aging, immunity, biochemical detection, and other factors. The discovery of abnormal DNA repair in cancers has been heralded as a paradigm shift in the treatment of malignancies. A poly (ADP-ribose) polymerase (PARP) activates poly (ADP-ribosylation) to repair single-strand DNA breaks after DNA damage. In some cancers, such as breast cancer and gastric cancer, a PARP inhibitor can target the DNA damage response pathway, prevent DNA repair, and induce homologous recombination deficiency (HRD) tumors to create the phenomena of synthetic lethality. Increasingly, clinical trials are being submitted to research the uses of PARP inhibitors in various types of cancers. Small cell lung cancer (SCLC) is a quickly growing malignancy with numerous therapeutic limitations and a dismal prognosis. Sequencing of mutant genes revealed multiple gene connections that may contribute to its carcinogenesis, indicating a viable study direction. Furthermore, the therapy of SCLC with PARP inhibitors has been further explored. The mechanism of PARP action, as well as the advancement of its preclinical and clinical applications in SCLC, will be discussed in this review.
DNA damage repair (DDR) system plays an important role in maintaining of genomic stability. Accumulation of DNA lesions or deficiency of DDR system could drive tumorigenesis as well as promote tumor progression; meanwhile, they could also provide therapeutic opportunities and targets. Of all the antineoplastic agents of lung cancers, many of them targeted or were associated with DNA damage and repair pathways, such as chemotherapies and antibody-drug conjugates which were designed directly causing DNA damages, targeted drugs inhibiting DNA repair pathways, and immune-checkpoint inhibitors. In this review, we described the role of DNA damage and repair pathways in antitumor activity of the above agents, as well as summarized the application and clinical investigations of these antineoplastic agents in lung cancers, in order to provide more information for exploring precision and effective strategies for the treatment of lung cancer based on the mechanism of DNA damage and repair.
.
Treatment for small cell lung cancer (SCLC) has not changed significantly compared to the overwhelming development of targeted therapies for non-small cell lung cancer. However, recent epigenetic and expressional analyses have revealed that SCLC can be divided into four distinct subtypes, which may lead to precision treatments. The situation appears slightly similar to the "four-color problem," a classic mathematical problem stating that no more than four colors are required to color the regions so that no two adjacent areas have the same color. This review introduces the framework for subtyping SCLC into four molecular subtypes and the promising targeted treatment for each subtype.
Introduction:
Small cell lung cancer (SCLC) is an aggressive malignancy with no established biomarkers. Schlafen 11(SLFN11), a DNA/RNA helicase that sensitises cancer cells to DNA-damaging agents, has emerged as a promising predictive biomarker for several drug classes including platinum and PARP inhibitors. Detection of SLFN11 in circulating tumour cells (CTCs) may provide a valuable alternative to tissue sampling.
Methods:
SLFN11 expression was evaluated in tumour samples and characterised in circulating tumour cells (CTC) longitudinally to determine its potential role as a biomarker of response.
Results:
Among 196 SCLC tumours, 51% expressed SLFN11 by IHC. In addition, 20/29 extra-thoracic high-grade neuroendocrine tumours expressed SLFN11 expression. In 64 blood samples from 42 SCLC patients, 83% (53/64) of samples had detectable CTCs, and SLFN11-positive CTCs were detected in 55% (29/53). Patients actively receiving platinum treatment had the lowest number of CTCs and a lower percentage of SLFN11-positive CTCs (p = 0.014). Analysis from patients with longitudinal samples suggest a decrease in CTC number and in SLFN11 expression that correlates with clinical response.
Conclusions:
SLFN11 levels can be monitored in CTCs from SCLC patients using non-invasive liquid biopsies. The ability to detect SLFN11 in CTCs from SCLC patients adds a valuable tool for the detection and longitudinal monitoring of this promising biomarker.
Extensive-stage small-cell lung cancer is a therapeutically challenging disease. After more than two decades without clinical progress, the addition of programmed cell death protein 1 axis blockade to platinum-based chemotherapy has demonstrated sustained overall survival benefit and represents the current standard of care in the first-line setting. Despite this benefit, resistance emerges relatively rapidly in virtually all patients. Although newer treatments are being incorporated in the relapse setting, marked therapeutic resistance is typically observed in patients with relapsed small-cell lung cancer (SCLC), underscoring the need of developing more effective therapies in this setting. Notably, recent progress in the understanding of the molecular biology of SCLC might bring possibilities toward molecularly informed therapeutic strategies for patients with SCLC, which could have a significant impact for improving outcomes in this disease. Here, we review current treatment options and recent progress made in the first-line and relapsed SCLC, including the role of biomarkers and new evolving therapeutic strategies.
Small cell lung cancer (SCLC) is a highly aggressive neuroendocrine malignancy with high and rapid relapse rates and poor outcomes. Treatment for SCLC has historically been limited by the lack of targetable driver genomic lesions, however recent developments in the underpinnings of genomic instability in SCLC and understanding of its transcriptional subtypes have led to increased interest in the use of poly(ADP-ribose) polymerase (PARP) inhibitors as a rationale therapy. Poly(ADP-ribose) polymerase inhibitors, historically designed to target BRCA1/2-mutated malignancies, capitalize on synthetic lethality in homologous recombination-deficient tumors. In this review, we outline the mechanistic rationale for the use of PARP inhibitors in treating SCLC and detail key clinical trials investigating their use in combination with chemotherapy and immunotherapy. We describe developments in the understanding of biomarkers for sensitivity to therapy and highlight further investigational directions for the use of PARP inhibitors in treating SCLC.
Purpose of review:
In this article, we aimed to summarize the recent progress being made in treatment of small cell lung cancer (SCLC).
Recent findings:
SCLC is characterized by strong invasiveness, easy recurrence and early metastasis. In recent years, the emergence of immune checkpoint inhibitors (ICIs) therapy has broken the deadlock in the treatment field of SCLC. Combination strategies, such as the addition of ICIs to chemotherapy and radiotherapy, are actively underway. Some of these strategies have yielded significant survival benefits and tolerable adverse events, whereas several of them have failed with no significant improvement. In addition, the new classification of SCLC based on genomic analysis has deepened the understanding of SCLC and suggested new therapeutic directions. Similarly, the discovery of some new therapeutic targets, such as DDL3, CDK7 and PARP, also brings new hope for improving the survival of patients with SCLC.
Summary:
In this article, we will review the recent advances of therapeutic regimen for patients with SCLC. Following the revolutionary success of adding ICIs to chemotherapy, more varieties of combination strategies have been explored in recent trials. In addition, therapeutic drug research and efficacy evaluation against for new targets are under investigation. Altogether, progress on genomic analysis, investigation of biological pathways and treatment regimen combination are providing renewed hope for patients with SCLC.
Extensive stage small cell lung cancer carries extremely poor prognosis and adding immune checkpoint inhibitor to the platinum etoposide combination in first line only improved the outcome modestly. Once disease recurs, treatment response is only transient in nature. Various strategies that are being explored include dual checkpoint blockade, BiTE and CAR-T cell approaches. Immune checkpoint inhibitors are being combined with PARP inhibitors. Other approaches currently being investigated include liposomal irinotecan and combining known active agents for SCLC in relapsed setting such as newly approved lurbinectedin with doxorubicin, paclitaxel, irinotecan or topotecan with ATR inhibitor (Berzosertib). Temozolomide has also been tested in combination with a parp inhibitor. New antibody or small molecule drug conjugates are being actively investigated so is a biomarker based approach. Better understanding of small cell lung cancer disease biology via high through-put genomic, proteomic and methylation profiling offer glimpse of hope in our efforts to contain this deadly disease. A table of representative molecular targets under investigation is provided in the end.
Small cell lung cancer (SCLC) is a very aggressive, highly lethal, neuroendocrine tumor that constitutes 15% of all lung cancer cases. It is characterized by its rapid disease progression and high relapse rate leading to poor survival for diagnosed patients. Recently, poly (ADP-ribose) polymerase inhibitors (PARPi) have emerged as a novel therapeutic strategy for SCLC. Preclinical studies have demonstrated that PARPi possesses cytotoxic activity as a single-agent and in combination with other anti-cancer agents. Predictive biomarkers of response to PARPi, such as SLFN11, have also been described in SCLC. This review aims to summarize the recent preclinical investigations and the relevant clinical trials that evaluate PARPi in SCLC. Here, we highlight the potential role of PARPi in a biomarker-selected manner and in combination with chemotherapy, targeted agents, radiotherapy and immunotherapy.
Background/aims:
The prognosis of small cell lung cancer (SCLC) is still poor because of rapid recurrence, despite good response to initial chemotherapy. Additionally, patients' old ages and comorbidities are often obstacles that make it difficult to apply subsequent treatment after initial treatment. This retrospective study analyzed the correlation of post-progression survival (PPS) with overall survival (OS), and prognostic factors including comorbidities to figure out impact of subsequent chemotherapy on OS in elderly extensive disease SCLC.
Methods:
We analyzed 101 patients of age 65 years or older who were recently diagnosed with extensive disease SCLC (ED-SCLC) in Korea University Medical Center between January 1995 and December 2015. The degree of comorbidity was scored using simplified comorbidity score (SCS). Correlation between PPS, progression-free survival (PFS) and OS was analyzed using a Pearson correlation coefficient. Cox proportional hazards regression was employed to examine the influence of clinical variables on survival.
Results:
Median age of patients was 71 years old (range, 65 to 83). Median OS was 8.7 months (range, 0.3 to 42.7). PPS was a reliable factor on OS than PFS (R2 = 0.852, p < 0.001). Prognostic factors associated with improved survival were SCS < 9, administration > 4 cycles of first line chemotherapy and subsequent second line chemotherapy.
Conclusions:
PPS was more correlated with OS than PFS in elderly patients with ED-SCLC. The most important prognostic factors for PPS and OS included SCS and second line chemotherapy. Patients receiving subsequent treatment had increased OS regardless of degree of comorbidity.
Small cell lung cancer (SCLC) is an exceptionally lethal malignancy for which more effective therapies are urgently needed. Several lines of evidence, from SCLC primary human tumours, patient-derived xenografts, cancer cell lines and genetically engineered mouse models, appear to be converging on a new model of SCLC subtypes defined by differential expression of four key transcription regulators: achaete-scute homologue 1 (ASCL1; also known as ASH1), neurogenic differentiation factor 1 (NeuroD1), yes-associated protein 1 (YAP1) and POU class 2 homeobox 3 (POU2F3). In this Perspectives article, we review and synthesize these recent lines of evidence and propose a working nomenclature for SCLC subtypes defined by relative expression of these four factors. Defining the unique therapeutic vulnerabilities of these subtypes of SCLC should help to focus and accelerate therapeutic research, leading to rationally targeted approaches that may ultimately improve clinical outcomes for patients with this disease.
Background
Small cell lung cancer (SCLC) is typically categorized according to disease extent as limited or extensive, and utility of the 8th TNM classification, recommended for lung cancer staging, which demonstrates a strong association with non-small-cell lung cancer (NSCLC) management, remains unclear.
Methods
This retrospective study included 277 consecutive SCLC patients treated at a single institution between 2008 and 2016.
Results
According to the currently used two-stage system, 186 (65.7%) of the patients were classified as having extensive disease (ED)-SCLC. Among the ED-SCLC patients, ten (5.3%), 38 (20.4%), 32 (17.2%), and 106 (57.0%) were categorized into stages M0, M1a, M1b, and M1c, respectively, according to the 8th TNM classification. There was a significant difference in overall survival based on the M descriptors: 15.8 (95% CI 9.4–22.2) months in the M1b group vs 7.3 (95% CI 5.7–8.9) months in the M1c group (P<0.001). Multivariate analysis showed that in addition to the known prognostic factors such as performance status, serum albumin, and lactate dehydrogenase, M descriptor was a prognostic factor (HR 1.95, 95% CI 1.38–2.77; P<0.001).
Conclusion
The 8th TNM classification has a prognostic value in SCLC. Similarly to NSCLC, treatment approaches should be considered on the basis of the 8th TNM classification, especially stage IVA separate from stage IVB in ED-SCLC patients.
PURPOSE:
This study examined safety, pharmacokinetics and efficacy of veliparib, a PARP inhibitor, combined with carboplatin and etoposide in patients with extensive-stage (ED) small cell lung cancer (SCLC) and other solid tumors.
EXPERIMENTAL DESIGN:
3+3 design was used for dose escalation of oral veliparib in combination with carboplatin (AUC 5 on Day 1) and etoposide (100 mg/m2 on Days 1-3) in 21-day cycles. Veliparib dose was explored from 80-240mg twice daily (BID) on 7-day, 14-day or continuous schedules. Patients without disease progression continued on maintenance monotherapy (veliparib 400mg BID) until disease progression or unacceptable toxicity.
RESULTS:
Thirty-nine patients were enrolled to determine the recommended phase 2 dose (RP2D) of 240 mg veliparib for 14-days combined with carboplatin and etoposide based on long-term tolerability. Dose-limiting toxicity occurred in one patient (grade 2 toxic motor polyneuropathy) at veliparib 240 mg BID 7-days. Most common adverse events related to veliparib were nausea (39%), fatigue (39%), and hematologic toxicities. Continuous dosing of veliparib 240 mg BID with carboplatin and etoposide resulted in excessive chemotherapy dose delays due to hematologic toxicity (grade 3/4 neutropenia/thrombocytopenia). Etoposide pharmacokinetics was not affected by veliparib. Confirmed responses occurred in 17/39 (44%) and 16/25 (64%) of all enrolled and ED SCLC patients, respectively. At the recommended phase 2 dose, confirmed responses occurred in 6/13 (46%) and 5/6 (83%) of all enrolled and ED SCLC patients, respectively.
CONCLUSIONS:
Veliparib (240mg BID 14-days) plus carboplatin/etoposide can be safely combined. Phase 2 of this study is ongoing in first-line patients with ED SCLC.
Background:
The aim of this study was to systematically evaluate the prognostic role of pretreatment lactate dehydrogenase (LDH) concentration for survival in patients with lung cancer through performing a meta-analysis.
Methods:
PubMed, EMBASE, Cochrane Library, Web of Science, and China National Knowledge Infrastructure were searched for potentially relevant literature. The study and patients' characteristics were extracted. Hazard ratios (HRs) with 95% confidence intervals (95% CIs) were pooled to estimate the prognostic role of LDH in patients with lung cancer.
Results:
Fourteen studies with 4084 patients were included. Higher pretreatment LDH concentration was significantly associated with an increased risk of overall mortality in patients with lung cancer (HR = 1.49, 95% CI, 1.38-1.59). Subgroup analysis of studies also resulted in a significantly increased risk of mortality in patients with small cell lung cancer (SCLC, HR = 1.54, 95% CI, 1.43-1.67) or nonsmall cell lung cancer (NSCLC, HR = 1.25, 95% CI, 1.06-1.46), with high pretreatment LDH concentration. No significant between-study heterogeneity was observed (I = 12.0%, P = .321). No significant publication bias was found (P = .352) in the meta-analysis.
Conclusion:
The results suggested that higher pretreatment LDH concentration was associated with worse overall survival in patients with lung cancer. The findings may assist future research on anticancer therapy by targeting LDH and help predict prognosis in lung cancer patients. However, high-quality studies are required to further research and support these associations. Moreover, confounding factors such as patient ethnicity and tumor type should be considered in future studies.
Background:
Patients with extensive-stage small cell lung cancer (ES-SCLC) often develop brain metastases. There is significant controversy regarding the benefit of prophylactic cranial irradiation (PCI) for patients with ES-SCLC. Our objective is to identify ES-SCLC patients who might be most likely to benefit from PCI.
Methods:
We retrospectively reviewed 173 patients with ES-SCLC treated between 2010-2015. Of these, 117 patients were initially diagnosed without brain metastases and received systemic chemotherapy. Following exclusion of patients who received PCI and less than 2 cycles of platinum doublet therapy, 93 patients remained. Patient records were reviewed for clinical and radiographic features previously identified as relevant risk factors. Primary outcome was brain metastasis-free survival (BMFS). Kaplan-Meier analysis, log-rank tests and Cox multivariate models were used to compare outcomes.
Results:
Median follow-up was 10.7 months (range, 3-58 months). Thirty-eight (40.9%) patients developed brain metastases. Three or more metastatic sites was associated with inferior BMFS on univariable (1-year estimate 43.8% vs. 61.3%; P=0.020) and multivariable (MVA) analysis [hazard ratio (HR) 2.33, 95% CI: 1.08-5.01; P=0.03).
Conclusions:
Our results suggest that extracranial metastatic burden is associated with an increased risk for brain metastases in patients with ES-SCLC. As there is no clear standard regarding delivery of PCI in this patient population, utilizing the number of metastatic disease sites as a clinical indicator may help to improve selection of patients who benefit from PCI.
Purpose
Both temozolomide (TMZ) and poly (ADP-ribose) polymerase (PARP) inhibitors are active in small-cell lung cancer (SCLC). This phase II, randomized, double-blind study evaluated whether addition of the PARP inhibitor veliparib to TMZ improves 4-month progression-free survival (PFS).
Patients and Methods
A total of 104 patients with recurrent SCLC were randomly assigned 1:1 to oral veliparib or placebo 40 mg twice daily, days 1 to 7, and oral TMZ 150 to 200 mg/m²/day, days 1 to 5, of a 28-day cycle until disease progression, unacceptable toxicity, or withdrawal of consent. Response was determined by imaging at weeks 4 and 8, and every 8 weeks thereafter. Improvement in PFS at 4 months was the primary end point. Secondary objectives included overall response rate (ORR), overall survival (OS), and safety and tolerability of veliparib with TMZ. Exploratory objectives included PARP-1 and SLFN11 immunohistochemical expression, MGMT promoter methylation, and circulating tumor cell quantification.
Results
No significant difference in 4-month PFS was noted between TMZ/veliparib (36%) and TMZ/placebo (27%; P = .19); median OS was also not improved significantly with TMZ/veliparib (8.2 months; 95% CI, 6.4 to 12.2 months; v 7.0 months; 95% CI, 5.3 to 9.5 months; P = .50). However, ORR was significantly higher in patients receiving TMZ/veliparib compared with TMZ/placebo (39% v 14%; P = .016). Grade 3/4 thrombocytopenia and neutropenia more commonly occurred with TMZ/veliparib: 50% versus 9% and 31% versus 7%, respectively. Significantly prolonged PFS (5.7 v 3.6 months; P = .009) and OS (12.2 v 7.5 months; P = .014) were observed in patients with SLFN11-positive tumors treated with TMZ/veliparib.
Conclusion
Four-month PFS and median OS did not differ between the two arms, whereas a significant improvement in ORR was observed with TMZ/veliparib. SLFN11 expression was associated with improved PFS and OS in patients receiving TMZ/veliparib, suggesting a promising biomarker of PARP-inhibitor sensitivity in SCLC.
The SCLC combination screen examined a 9-point concentration response of 180 third agents, alone and in combination with etoposide/carboplatin. The predominant effect of adding a third agent to etoposide/carboplatin was additivity. Less than additive effects occurred frequently in SCLC lines sensitive to etoposide/carboplatin. In SCLC lines with little or no response to etoposide/carboplatin, greater than additive SCLC killing occurred over the entire spectrum of SCLC lines but never occurred in all SCLC lines. Exposing SCLC lines to tubulin-targeted agents (paclitaxel or vinorelbine) simultaneously with etoposide/carboplatin resulted primarily in less than additive cell killing. As single agents, nuclear kinase inhibitors including Aurora kinase inhibitors, Kinesin Spindle Protein/EG5 inhibitors, and Polo-like kinase-1 inhibitors were potent cytotoxic agents in SCLC lines; however, simultaneous exposure of the SCLC lines to these agents along with etoposide/carboplatin, generally, resulted in less than additive cell killing. Several classes of agents enhanced the cytotoxicity of etoposide/carboplatin toward the SCLC lines. Exposure of the SCLC lines to the MDM2 inhibitor JNJ-27291199 produced enhanced killing in 80% of the SCLC lines. Chk-1 inhibitors such as rabusertib increased the cytotoxicity of etoposide/carboplatin to the SCLC lines in an additive to greater than additive manner. The combination of GSK-3β inhibitor LY-2090314 with etoposide/carboplatin increased killing in approximately 40% of the SCLC lines. Exposure to the BET bromodomain inhibitor MK-8628 increased the SCLC cell killing by etoposide/carboplatin in 20–25% of the SCLC lines. Only 10–15% of the SCLC lines had an increased response to etoposide/carboplatin when simultaneously exposed to the PARP inhibitor talazoparib.
Background:
Small cell lung cancer (SCLC) frequently leads to development of brain metastases. These unfortunately continue to be associated with short survival. Substantial advances have been made in our understanding of the underlying biology of disease. This understanding on the background of previously evaluated and currently utilized therapeutic treatments can help guide the next steps in investigations into this disease with the potential to influence future treatments.
Design:
A comprehensive review of the literature covering epidemiology, pathophysiology, imaging characteristics, prognosis, and therapeutic management of SCLC brain metastases was performed.
Results:
SCLC brain metastases continue to have a poor prognosis. Both unique aspects of SCLC brain metastases as well as features seen more universally across other solid tumor brain metastases are discussed. Systemic therapeutic studies and radiotherapeutic approaches are reviewed.
Conclusions:
A clearer understanding of SCLC brain metastases will help lay the framework for studies which will hopefully translate into meaningful therapeutic options for these patients.
Small cell lung cancer (SCLC) is one of the most aggressive forms of cancer, with a 5-year survival <7%. A major barrier to progress is the absence of predictive biomarkers for chemotherapy and novel targeted agents such as PARP inhibitors. Using a high-throughput, integrated proteomic, transcriptomic, and genomic analysis of SCLC patient-derived xenografts (PDXs) and profiled cell lines, we identified biomarkers of drug sensitivity and determined their prevalence in patient tumors. In contrast to breast and ovarian cancer, PARP inhibitor response was not associated with mutations in homologous recombination (HR) genes (e.g., BRCA1/2) or HRD scores. Instead, we found several proteomic markers that predicted PDX response, including high levels of SLFN11 and E-cadherin and low ATM. SLFN11 and E-cadherin were also significantly associated with in vitro sensitivity to cisplatin and topoisomerase1/2 inhibitors (all commonly used in SCLC). Treatment with cisplatin or PARP inhibitors downregulated SLFN11 and E-cadherin, possibly explaining the rapid development of therapeutic resistance in SCLC. Supporting their functional role, silencing SLFN11 reduced in vitro sensitivity and drug-induced DNA damage; whereas ATM knockdown or pharmacologic inhibition enhanced sensitivity. Notably, SCLC with mesenchymal phenotypes (i.e., loss of E-cadherin and high epithelial-to-mesenchymal transition (EMT) signature scores) displayed striking alterations in expression of miR200 family and key SCLC genes (e.g., NEUROD1, ASCL1, ALDH1A1, MYCL1). Thus, SLFN11, EMT, and ATM mediate therapeutic response in SCLC and warrant further clinical investigation as predictive biomarkers.
Purpose:
PARP inhibitors (PARPi) are a novel class of small molecule therapeutics for small cell lung cancer (SCLC). Identification of predictors of response would advance our understanding, and guide clinical application, of this therapeutic strategy.
Experimental design:
Efficacy of PARP inhibitors olaparib, rucaparib, and veliparib, as well as etoposide and cisplatin in SCLC cell lines, and gene expression correlates, were analyzed using public datasets. HRD genomic scar scores were calculated from Affymetrix SNP 6.0 arrays. In vitro talazoparib efficacy was measured by cell viability assays. For functional studies, CRISPR-Cas9 and shRNA were used for genomic editing and transcript knockdown, respectively. Protein levels were assessed by immunoblotting and immunohistochemistry (IHC). Quantitative synergy of talazoparib and temozolomide were determined in vitro. In vivo efficacy of talazoparib, temozolomide, and the combination was assessed in patient-derived xenograft (PDX) models.
Results:
We identified SLFN11, but not HRD genomic scars, as a consistent correlate of response to all three PARPi assessed, with loss of SLFN11 conferring resistance to PARPi. We confirmed these findings in vivo across multiple PDX and defined IHC staining for SLFN11 as a predictor of talazoparib response. As temozolomide has activity in SCLC, we investigated combination therapy with talazoparib and found marked synergy in vitro and efficacy in vivo, which did not solely depend on SLFN11 or MGMT status.
Conclusions:
SLFN11 is a relevant predictive biomarker of sensitivity to PARP inhibitor monotherapy in SCLC and we identify combinatorial therapy with TMZ as a particularly promising therapeutic strategy that warrants further clinical investigation.
. The effects of first-line chemotherapy on overall survival (OS) might be confounded by subsequent therapies in patients with small-cell lung cancer (SCLC). Therefore, by using individual-level data, we aimed to determine the relationships between progression-free survival (PFS) or postprogression survival (PPS) and OS after first-line chemotherapies in patients with extensive disease-SCLC (ED-SCLC) treated with carboplatin plus etoposide.
Methods
. Between July 1998 and December 2014, we analyzed 63 cases of patients with ED-SCLC who were treated with carboplatin and etoposide as first-line chemotherapy. The relationships of PFS and PPS with OS were analyzed at the individual level.
Results
. Spearman rank correlation analysis and linear regression analysis showed that PPS was strongly correlated with OS (
r
=
0.90
,
p
<
0.05
, and
R
2
=
0.71
) and PFS was moderately correlated with OS (
r
=
0.72
,
p
<
0.05
, and
R
2
=
0.62
). Type of relapse (refractory/sensitive) and the number of regimens administered after disease progression after the first-line chemotherapy were both significantly associated with PPS (
p
<
0.05
).
Conclusions
. PPS has a stronger relationship with OS than does PFS in ED-SCLC patients who have received first-line chemotherapy. These results suggest that treatments administered after first-line chemotherapy affect the OS of ED-SCLC patients treated with carboplatin plus etoposide.
We have sequenced the genomes of 110 small cell lung cancers (SCLC), one of the deadliest human cancers. In nearly all the tumours analysed we found bi-allelic inactivation of TP53 and RB1, sometimes by complex genomic rearrangements. Two tumours with wild-type RB1 had evidence of chromothripsis leading to overexpression of cyclin D1 (encoded by the CCND1 gene), revealing an alternative mechanism of Rb1 deregulation. Thus, loss of the tumour suppressors TP53 and RB1 is obligatory in SCLC. We discovered somatic genomic rearrangements of TP73 that create an oncogenic version of this gene, TP73Δex2/3. In rare cases, SCLC tumours exhibited kinase gene mutations, providing a possible therapeutic opportunity for individual patients. Finally, we observed inactivating mutations in NOTCH family genes in 25% of human SCLC. Accordingly, activation of Notch signalling in a pre-clinical SCLC mouse model strikingly reduced the number of tumours and extended the survival of the mutant mice. Furthermore, neuroendocrine gene expression was abrogated by Notch activity in SCLC cells. This first comprehensive study of somatic genome alterations in SCLC uncovers several key biological processes and identifies candidate therapeutic targets in this highly lethal form of cancer.
Poly (ADP) ribose polymerase (PARP) plays a key role in DNA repair and is highly expressed in small cell lung cancer (SCLC). We investigated the therapeutic impact of PARP inhibition in SCLC. In vitro cytotoxicity of veliparib, cisplatin, carboplatin, and etoposide singly and combined was determined by MTS in 9 SCLC cell lines (H69, H128, H146, H526, H187, H209, DMS53, DMS153, and DMS114). Subcutaneous xenografts in athymic nu/nu mice of H146 and H128 cells with relatively high and low platinum sensitivity, respectively, were employed for in vivo testing. Mechanisms of differential sensitivity of SCLC cell lines to PARP inhibition were investigated by comparing protein and gene expression profiles of the platinum sensitive and the less sensitive cell lines. Veliparib showed limited single-agent cytotoxicity but selectively potentiated (≥50% reduction in IC50) cisplatin, carboplatin, and etoposide in vitro in five of nine SCLC cell lines. Veliparib with cisplatin or etoposide or with both cisplatin and etoposide showed greater delay in tumor growth than chemotherapy alone in H146 but not H128 xenografts. The potentiating effect of veliparib was associated with in vitro cell line sensitivity to cisplatin (CC = 0.672; P = 0.048) and DNA-PKcs protein modulation. Gene expression profiling identified differential expression of a 5-gene panel (GLS, UBEC2, HACL1, MSI2, and LOC100129585) in cell lines with relatively greater sensitivity to platinum and veliparib combination. Veliparib potentiates standard cytotoxic agents against SCLC in a cell-specific manner. This potentiation correlates with platinum sensitivity, DNA-PKcs expression and a 5-gene expression profile.
All cancers are caused by somatic mutations; however, understanding of the biological processes generating these mutations is limited. The catalogue of somatic mutations from a cancer genome bears the signatures of the mutational processes that have been operative. Here we analysed 4,938,362 mutations from 7,042 cancers and extracted more than 20 distinct mutational signatures. Some are present in many cancer types, notably a signature attributed to the APOBEC family of cytidine deaminases, whereas others are confined to a single cancer class. Certain signatures are associated with age of the patient at cancer diagnosis, known mutagenic exposures or defects in DNA maintenance, but many are of cryptic origin. In addition to these genome-wide mutational signatures, hypermutation localized to small genomic regions, ‘kataegis’, is found in many cancer types. The results reveal the diversity of mutational processes underlying the development of cancer, with potential implications for understanding of cancer aetiology, prevention and therapy.
DNA-damaging agents (DDAs) constitute the backbone of treatment for most human tumors. Here we used the National Cancer Institute Antitumor Cell Line Panel (the NCI-60) to identify predictors of cancer cell response to topoisomerase I (Top1) inhibitors, a widely used class of DDAs. We assessed the NCI-60 transcriptome using Affymetrix Human Exon 1.0 ST microarrays and correlated the in vitro activity of four Top1 inhibitors with gene expression in the 60 cell lines. A single gene, Schlafen-11 (SLFN11), showed an extremely significant positive correlation with the response not only to Top1 inhibitors, but also to Top2 inhibitors, alkylating agents, and DNA synthesis inhibitors. Using cells with endogenously high and low SLFN11 expression and siRNA-mediated silencing, we show that SLFN11 is causative in determining cell death and cell cycle arrest in response to DDAs in cancer cells from different tissues of origin. We next analyzed SLFN11 expression in ovarian and colorectal cancers and normal corresponding tissues from The Cancer Genome Atlas database and observed that SLFN11 has a wide expression range. We also observed that high SLFN11 expression independently predicts overall survival in a group of ovarian cancer patients treated with cisplatin-containing regimens. We conclude that SLFN11 expression is causally associated with the activity of DDAs in cancer cells, has a broad expression range in colon and ovarian adenocarcinomas, and may behave as a biomarker for prediction of response to DDAs in the clinical setting.
In advanced non-small-cell lung cancer (NSCLC), with the increasing number of active compounds available in salvage settings, survival after progression to first-line chemotherapy seems to have improved. A literature survey was conducted to examine whether survival post-progression (SPP) has improved over the years and to what degree SPP correlates with overall survival (OS).
Median progression-free survival (MPFS) time and median survival time (MST) were extracted in phase III trials of first-line chemotherapy for advanced NSCLC. SPP was pragmatically defined as the time interval of MST minus MPFS. The relationship between MPFS and MST was modeled in a linear function. We used the coefficient of determination (r(2)) to assess the correlation between them. Seventy trials with 145 chemotherapy arms were identified. Overall, median SPP was 4.7 months, and a steady improvement in SPP was observed over the 20 years (9.414-day increase per year; p<0.001) in parallel to the increase in MST (11.253-day increase per year; p<0.001); MPFS improved little (1.863-day increase per year). Overall, a stronger association was observed between MST and SPP (r(2) = 0.8917) than MST and MPFS time (r(2) = 0.2563), suggesting SPP and MPFS could account for 89% and 25% of the variation in MST, respectively. The association between MST and SPP became closer over the years (r(2) = 0.4428, 0.7242, and 0.9081 in 1988-1994, 1995-2001, and 2002-2007, respectively).
SPP has become more closely associated with OS, potentially because of intensive post-study treatments. Even in advanced NSCLC, a PFS advantage is unlikely to be associated with an OS advantage any longer due to this increasing impact of SPP on OS, and that the prolongation of SPP might limit the original role of OS for assessing true efficacy derived from early-line chemotherapy in future clinical trials.
ADP-ribosylation is an enzyme-catalyzed posttranslational protein modification in which mono(ADP-ribosyl)transferases (mARTs) and poly(ADP-ribosyl)transferases (pARTs) transfer the ADP-ribose moiety from NAD onto specific amino acid side chains and/or ADP-ribose units on target proteins.
Using a combination of database search tools we identified the genes encoding recognizable pART domains in the public genome databases. In humans, the pART family encompasses 17 members. For 16 of these genes, an orthologue exists also in the mouse, rat, and pufferfish. Based on the degree of amino acid sequence similarity in the catalytic domain, conserved intron positions, and fused protein domains, pARTs can be divided into five major subgroups. All six members of groups 1 and 2 contain the H-Y-E trias of amino acid residues found also in the active sites of Diphtheria toxin and Pseudomonas exotoxin A, while the eleven members of groups 3 - 5 carry variations of this motif. The pART catalytic domain is found associated in Lego-like fashion with a variety of domains, including nucleic acid-binding, protein-protein interaction, and ubiquitylation domains. Some of these domain associations appear to be very ancient since they are observed also in insects, fungi, amoebae, and plants. The recently completed genome of the pufferfish T. nigroviridis contains recognizable orthologues for all pARTs except for pART7. The nearly completed albeit still fragmentary chicken genome contains recognizable orthologues for twelve pARTs. Simpler eucaryotes generally contain fewer pARTs: two in the fly D. melanogaster, three each in the mosquito A. gambiae, the nematode C. elegans, and the ascomycete microfungus G. zeae, six in the amoeba E. histolytica, nine in the slime mold D. discoideum, and ten in the cress plant A. thaliana. GenBank contains two pART homologues from the large double stranded DNA viruses Chilo iridescent virus and Bacteriophage Aeh1 and only a single entry (from V. cholerae) showing recognizable homology to the pART-like catalytic domains of Diphtheria toxin and Pseudomonas exotoxin A.
The pART family, which encompasses 17 members in the human and 16 members in the mouse, can be divided into five subgroups on the basis of sequence similarity, phylogeny, conserved intron positions, and patterns of genetically fused protein domains.
Despite molecular and clinical heterogeneity, small cell lung cancer (SCLC) is treated as a single entity with predictably poor results. Using tumor expression data and non-negative matrix factorization, we identify four SCLC subtypes defined largely by differential expression of transcription factors ASCL1, NEUROD1, and POU2F3 or low expression of all three transcription factor signatures accompanied by an Inflamed gene signature (SCLC-A, N, P, and I, respectively). SCLC-I experiences the greatest benefit from the addition of immunotherapy to chemotherapy, while the other subtypes each have distinct vulnerabilities, including to inhibitors of PARP, Aurora kinases, or BCL-2. Cisplatin treatment of SCLC-A patient-derived xenografts induces intratumoral shifts toward SCLC-I, supporting subtype switching as a mechanism of acquired platinum resistance. We propose that matching baseline tumor subtype to therapy, as well as manipulating subtype switching on therapy, may enhance depth and duration of response for SCLC patients.
Background
BRCA1 or BRCA2-mutated breast cancers are sensitive to poly(ADP-ribose) polymerase (PARP) inhibitors and platinum agents owing to deficiency in homologous recombination repair of DNA damage. In this trial, we compared veliparib versus placebo in combination with carboplatin and paclitaxel, and continued as monotherapy if carboplatin and paclitaxel were discontinued before progression, in patients with HER2-negative advanced breast cancer and a germline BRCA1 or BRCA2 mutation.
Methods
BROCADE3 was a randomised, double-blind, placebo-controlled, phase 3 trial done at 147 hospitals in 36 countries. Eligible patients (aged ≥18 years) had deleterious germline BRCA1 or BRCA2 mutation-associated, histologically or cytologically confirmed advanced HER2-negative breast cancer, an Eastern Cooperative Oncology Group performance status of 0–2, and had received up to two previous lines of chemotherapy for metastatic disease. Patients were randomly assigned (2:1) by interactive response technology by means of permuted blocks within strata (block size of 3 or 6) to carboplatin (area under the concentration curve 6 mg/mL per min intravenously) on day 1 and paclitaxel (80 mg/m² intravenously) on days 1, 8, and 15 of 21-day cycles combined with either veliparib (120 mg orally twice daily, on days −2 to 5) or matching placebo. If patients discontinued carboplatin and paclitaxel before progression, they could continue veliparib or placebo at an intensified dose (300 mg twice daily continuously, escalating to 400 mg twice daily if tolerated) until disease progression. Patients in the control group could receive open-label veliparib monotherapy after disease progression. Randomisation was stratified by previous platinum use, history of CNS metastases, and oestrogen and progesterone receptor status. The primary endpoint was investigator-assessed progression-free survival per Response Evaluation Criteria in Solid Tumors version 1.1. Efficacy analyses were done by intention to treat, which included all randomly assigned patients with a centrally confirmed BRCA mutation, and safety analyses included all patients who received at least one dose of velilparib or placebo. This study is ongoing and is registered with ClinicalTrials.gov, NCT02163694.
Findings
Between July 30, 2014, and Jan 17, 2018, 2202 patients were screened, of whom 513 eligible patients were enrolled and randomly assigned. In the intention-to-treat population (n=509), 337 patients were assigned to receive veliparib plus carboplatin–paclitaxel (veliparib group) and 172 were assigned to receive placebo plus carboplatin–paclitaxel (control group). Median follow-up at data cutoff (April 5, 2019) was 35·7 months (IQR 24·9–43·6) in the veliparib group and 35·5 months (23·1–45·9) in the control group. Median progression-free survival was 14·5 months (95% CI 12·5–17·7) in the veliparib group versus 12·6 months (10·6–14·4) in the control group (hazard ratio 0·71 [95% CI 0·57–0·88], p=0·0016). The most common grade 3 or worse adverse events were neutropenia (272 [81%] of 336 patients in the veliparib group vs 143 [84%] of 171 patients in the control group), anaemia (142 [42%] vs 68 [40%]), and thrombocytopenia (134 [40%] vs 48 [28%]). Serious adverse events occurred in 115 (34%) patients in the veliparib group versus 49 (29%) patients in the control group. There were no study drug-related deaths.
Interpretation
The addition of veliparib to a highly active platinum doublet, with continuation as monotherapy if the doublet were discontinued, resulted in significant and durable improvement in progression-free survival in patients with germline BRCA mutation-associated advanced breast cancer. These data indicate the utility of combining platinum and PARP inhibitors in this patient population.
Funding
AbbVie.
Purpose:
Pembrolizumab monotherapy has shown antitumor activity in patients with small-cell lung cancer (SCLC). The randomized, double-blind, phase III KEYNOTE-604 study compared pembrolizumab plus etoposide and platinum (EP) with placebo plus EP for patients with previously untreated extensive-stage (ES) SCLC.
Methods:
Eligible patients were randomly assigned 1:1 to pembrolizumab 200 mg once every 3 weeks or saline placebo for up to 35 cycles plus 4 cycles of EP. Primary end points were progression-free survival (PFS; RECIST version 1.1, blinded central review) and overall survival (OS) in the intention-to-treat population. Objective response rate (ORR) and duration of response were secondary end points. Prespecified efficacy boundaries were one-sided P = .0048 for PFS and .0128 for OS.
Results:
Of the 453 participants, 228 were randomly assigned to pembrolizumab plus EP and 225 to placebo plus EP. Pembrolizumab plus EP significantly improved PFS (hazard ratio [HR], 0.75; 95% CI, 0.61 to 0.91; P = .0023). Twelve-month PFS estimates were 13.6% with pembrolizumab plus EP and 3.1% with placebo plus EP. Although pembrolizumab plus EP prolonged OS, the significance threshold was not met (HR, 0.80; 95% CI, 0.64 to 0.98; P = .0164). Twenty-four-month OS estimates were 22.5% and 11.2%, respectively. ORR was 70.6% in the pembrolizumab plus EP group and 61.8% in the placebo plus EP group; the estimated proportion of responders remaining in response at 12 months was 19.3% and 3.3%, respectively. In the pembrolizumab plus EP and placebo plus EP groups, respectively, any-cause adverse events were grade 3-4 in 76.7% and 74.9%, grade 5 in 6.3% and 5.4%, and led to discontinuation of any drug in 14.8% and 6.3%.
Conclusion:
Pembrolizumab plus EP significantly improved PFS compared with placebo plus EP as first-line therapy for patients with ES-SCLC. No unexpected toxicities were seen with pembrolizumab plus EP. These data support the benefit of pembrolizumab in ES-SCLC.
Background:
Most patients with small-cell lung cancer (SCLC) have extensive-stage disease at presentation, and prognosis remains poor. Recently, immunotherapy has demonstrated clinical activity in extensive-stage SCLC (ES-SCLC). The CASPIAN trial assessed durvalumab, with or without tremelimumab, in combination with etoposide plus either cisplatin or carboplatin (platinum-etoposide) in treatment-naive patients with ES-SCLC.
Methods:
This randomised, open-label, phase 3 trial was done at 209 sites across 23 countries. Eligible patients were adults with untreated ES-SCLC, with WHO performance status 0 or 1 and measurable disease as per Response Evaluation Criteria in Solid Tumors, version 1.1. Patients were randomly assigned (in a 1:1:1 ratio) to durvalumab plus platinum-etoposide; durvalumab plus tremelimumab plus platinum-etoposide; or platinum-etoposide alone. All drugs were administered intravenously. Platinum-etoposide consisted of etoposide 80-100 mg/m2 on days 1-3 of each cycle with investigator's choice of either carboplatin area under the curve 5-6 mg/mL per min or cisplatin 75-80 mg/m2 (administered on day 1 of each cycle). Patients received up to four cycles of platinum-etoposide plus durvalumab 1500 mg with or without tremelimumab 75 mg every 3 weeks followed by maintenance durvalumab 1500 mg every 4 weeks in the immunotherapy groups and up to six cycles of platinum-etoposide every 3 weeks plus prophylactic cranial irradiation (investigator's discretion) in the platinum-etoposide group. The primary endpoint was overall survival in the intention-to-treat population. We report results for the durvalumab plus platinum-etoposide group versus the platinum-etoposide group from a planned interim analysis. Safety was assessed in all patients who received at least one dose of their assigned study treatment. This study is registered at ClinicalTrials.gov, NCT03043872, and is ongoing.
Findings:
Patients were enrolled between March 27, 2017, and May 29, 2018. 268 patients were allocated to the durvalumab plus platinum-etoposide group and 269 to the platinum-etoposide group. Durvalumab plus platinum-etoposide was associated with a significant improvement in overall survival, with a hazard ratio of 0·73 (95% CI 0·59-0·91; p=0·0047]); median overall survival was 13·0 months (95% CI 11·5-14·8) in the durvalumab plus platinum-etoposide group versus 10·3 months (9·3-11·2) in the platinum-etoposide group, with 34% (26·9-41·0) versus 25% (18·4-31·6) of patients alive at 18 months. Any-cause adverse events of grade 3 or 4 occurred in 163 (62%) of 265 treated patients in the durvalumab plus platinum-etoposide group and 166 (62%) of 266 in the platinum-etoposide group; adverse events leading to death occurred in 13 (5%) and 15 (6%) patients.
Interpretation:
First-line durvalumab plus platinum-etoposide significantly improved overall survival in patients with ES-SCLC versus a clinically relevant control group. Safety findings were consistent with the known safety profiles of all drugs received.
Funding:
AstraZeneca.
Background:
Data are limited regarding the use of poly(adenosine diphosphate [ADP]-ribose) polymerase inhibitors, such as veliparib, in combination with chemotherapy followed by maintenance as initial treatment in patients with high-grade serous ovarian carcinoma.
Methods:
In an international, phase 3, placebo-controlled trial, we assessed the efficacy of veliparib added to first-line induction chemotherapy with carboplatin and paclitaxel and continued as maintenance monotherapy in patients with previously untreated stage III or IV high-grade serous ovarian carcinoma. Patients were randomly assigned in a 1:1:1 ratio to receive chemotherapy plus placebo followed by placebo maintenance (control), chemotherapy plus veliparib followed by placebo maintenance (veliparib combination only), or chemotherapy plus veliparib followed by veliparib maintenance (veliparib throughout). Cytoreductive surgery could be performed before initiation or after 3 cycles of trial treatment. Combination chemotherapy was 6 cycles, and maintenance therapy was 30 additional cycles. The primary end point was investigator-assessed progression-free survival in the veliparib-throughout group as compared with the control group, analyzed sequentially in the BRCA-mutation cohort, the cohort with homologous-recombination deficiency (HRD) (which included the BRCA-mutation cohort), and the intention-to-treat population.
Results:
A total of 1140 patients underwent randomization. In the BRCA-mutation cohort, the median progression-free survival was 34.7 months in the veliparib-throughout group and 22.0 months in the control group (hazard ratio for progression or death, 0.44; 95% confidence interval [CI], 0.28 to 0.68; P<0.001); in the HRD cohort, it was 31.9 months and 20.5 months, respectively (hazard ratio, 0.57; 95 CI, 0.43 to 0.76; P<0.001); and in the intention-to-treat population, it was 23.5 months and 17.3 months (hazard ratio, 0.68; 95% CI, 0.56 to 0.83; P<0.001). Veliparib led to a higher incidence of anemia and thrombocytopenia when combined with chemotherapy as well as of nausea and fatigue overall.
Conclusions:
Across all trial populations, a regimen of carboplatin, paclitaxel, and veliparib induction therapy followed by veliparib maintenance therapy led to significantly longer progression-free survival than carboplatin plus paclitaxel induction therapy alone. The independent value of adding veliparib during induction therapy without veliparib maintenance was less clear. (Funded by AbbVie; VELIA/GOG-3005 ClinicalTrials.gov number, NCT02470585.).
Small-cell lung cancer (SCLC) is an aggressive disease with distinct pathological, clinical, and molecular characteristics from non-small-cell lung cancer. SCLC has high metastatic potential, resulting in a clinically poor prognosis. Early concurrent chemo-radiation is the standard of care for limited-stage SCLC (LS-SCLC). Prophylactic cranial irradiation (PCI) is recommended for patients with LS-SCLC without progression of disease after initial therapy. A combination of etoposide and cisplatin or carboplatin remains the mainstay of first-line treatment for ES-SCLC, with the addition of atezolizumab, now becoming standard. Most SCLCs initially respond to therapy but almost invariably recur. Topotecan and amrubicin (in Japan) remain the primary chemotherapy options for relapsed SCLC. Immunotherapy, including nivolumab with or without ipilimumab, is now available for refractory disease. In general, the poor prognosis of SCLC has not improved significantly for more than 3 decades. Recently, next-generation molecular profiling studies have identified new therapeutic targets for SCLC. A variety of proapoptotic agents, compounds capitalizing on DNA-repair defects, immunotherapy agents, and antibody-drug conjugates are being evaluated in SCLC, with a number of them showing early promise.
Purpose:
Veliparib, a poly (ADP ribose) polymerase inhibitor, potentiated standard chemotherapy against small-cell lung cancer (SCLC) in preclinical studies. We evaluated the combination of veliparib with cisplatin and etoposide (CE; CE+V) doublet in untreated, extensive-stage SCLC (ES-SCLC).
Materials and methods:
Patients with ES-SCLC, stratified by sex and serum lactate dehydrogenase levels, were randomly assigned to receive four 3-week cycles of CE (75 mg/m2 intravenously on day 1 and 100 mg/m2 on days 1 through 3) along with veliparib (100 mg orally twice per day on days 1 through 7) or placebo (CE+P). The primary end point was progression-free survival (PFS). Using an overall one-sided 0.10-level log-rank test, the study had 88% power to demonstrate a 37.5% reduction in the PFS hazard rate.
Results:
A total of 128 eligible patients received treatment on protocol. The median age was 66 years, 52% of patients were men, and Eastern Cooperative Oncology Group performance status was 0 for 29% of patients and 1 for 71%. The respective median PFS for the CE+V arm versus the CE+P arm was 6.1 versus 5.5 months (unstratified hazard ratio [HR], 0.75 [one-sided P = .06]; stratified HR, 0.63 [one-sided P = .01]), favoring CE+V. The median overall survival was 10.3 versus 8.9 months (stratified HR, 0.83; 80% CI, 0.64 to 1.07; one-sided P = .17) for the CE+V and CE+P arms, respectively. The overall response rate was 71.9% versus 65.6% (two-sided P = .57) for CE+V and CE+P, respectively. There was a significant treatment-by-strata interaction in PFS: Male patients with high lactate dehydrogenase levels derived significant benefit (PFS HR, 0.34; 80% CI, 0.22 to 0.51) but there was no evidence of benefit among patients in other strata (PFS HR, 0.81; 80% CI, 0.60 to 1.09). The following grade ≥ 3 hematology toxicities were more frequent in the CE+V arm than the CE+P arm: CD4 lymphopenia (8% v 0%; P = .06) and neutropenia (49% v 32%; P = .08), but treatment delivery was comparable.
Conclusion:
The addition of veliparib to frontline chemotherapy showed signal of efficacy in patients with ES-SCLC and the study met its prespecified end point.
Background
Enhancing tumor-specific T-cell immunity by inhibiting programmed death ligand 1 (PD-L1)–programmed death 1 (PD-1) signaling has shown promise in the treatment of extensive-stage small-cell lung cancer. Combining checkpoint inhibition with cytotoxic chemotherapy may have a synergistic effect and improve efficacy.
Methods
We conducted this double-blind, placebo-controlled, phase 3 trial to evaluate atezolizumab plus carboplatin and etoposide in patients with extensive-stage small-cell lung cancer who had not previously received treatment. Patients were randomly assigned in a 1:1 ratio to receive carboplatin and etoposide with either atezolizumab or placebo for four 21-day cycles (induction phase), followed by a maintenance phase during which they received either atezolizumab or placebo (according to the previous random assignment) until they had unacceptable toxic effects, disease progression according to Response Evaluation Criteria in Solid Tumors, version 1.1, or no additional clinical benefit. The two primary end points were investigator-assessed progression-free survival and overall survival in the intention-to-treat population.
Results
A total of 201 patients were randomly assigned to the atezolizumab group, and 202 patients to the placebo group. At a median follow-up of 13.9 months, the median overall survival was 12.3 months in the atezolizumab group and 10.3 months in the placebo group (hazard ratio for death, 0.70; 95% confidence interval [CI], 0.54 to 0.91; P=0.007). The median progression-free survival was 5.2 months and 4.3 months, respectively (hazard ratio for disease progression or death, 0.77; 95% CI, 0.62 to 0.96; P=0.02). The safety profile of atezolizumab plus carboplatin and etoposide was consistent with the previously reported safety profile of the individual agents, with no new findings observed.
Conclusions
The addition of atezolizumab to chemotherapy in the first-line treatment of extensive-stage small-cell lung cancer resulted in significantly longer overall survival and progression-free survival than chemotherapy alone. (Funded by F. Hoffmann–La Roche/Genentech; IMpower133 ClinicalTrials.gov number, NCT02763579.)
Background:
Thirty-day mortality after treatment for lung cancer is a measure of unsuccessful outcome and where treatment should have been avoided. Guidelines recommend offering chemotherapy to individuals with small-cell lung cancer (SCLC) who have poorer performance status (PS) because of its high initial response rate. However, this comes with an increased risk of toxicity and early death. We quantified real-world 30-day mortality in SCLC after chemotherapy, established the factors associated with this and compared these with the factors that influence receipt of chemotherapy.
Methods:
We used linked national English data sets to define the factors associated with both receiving chemotherapy and 30-day mortality after chemotherapy.
Results:
We identified 3715 people diagnosed with SCLC, of which 2235 (60.2%) received chemotherapy. There were 174 (7.8%) deaths within 30 days of chemotherapy. The adjusted odds of receiving chemotherapy decreased with older age, worsening PS and increasing comorbidities. Thirty-day mortality was independently associated with poor PS [PS 2 vs PS 0, adjusted odds ratio (OR) 3.75, 95% confidence interval (CI) 1.71-8.25] and stage (extensive vs limited adjusted OR 1.68, 95% CI 1.03-2.74) but in contrast was not associated with increasing age. Both chemotherapy administration and 30-day mortality varied by hospital network.
Conclusions:
To reduce variation in chemotherapy administration, predictors of 30-day mortality could be used as an adjunct to improve suboptimal patient selection. We have quantified 30-day mortality risk by the two independently associated factors, PS and stage, so that patients and clinicians can make better informed decisions about the potential risk of early death after chemotherapy.
Small cell lung cancer (SCLC) is an aggressive malignancy that accounts for 14% of all lung cancer diagnoses. Despite decades of active research, treatment options for SCLC are limited and resistance to the few Food and Drug Administration (FDA) approved therapies develops rapidly. With no approved targeted agents to date, new therapeutic strategies are desperately needed. SCLC is characterized by high mutation burden, ubiquitous loss of TP53 and RB1, mutually exclusive amplification of MYC family members, thereby, high genomic instability. Studies in the past few years have demonstrated the potential of targeting the DNA damage response (DDR) pathway as a promising therapeutic strategy for SCLC. Inhibitors targeting DDR proteins have shown promise in preclinical models, and are under clinical investigation as single agents and in combination with cytotoxic therapies. Recent efforts to expand the therapeutic arsenal toward SCLC have focused in part on immune checkpoint inhibitors, such as agents targeting the receptor-ligand pair programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1). Clinical trials have confirmed activity of these agents in extensive stage (ES)-SCLC. However, while several patients had dramatic responses, overall response rates to immune checkpoint blockade (ICB) remain poor. As a result, there is an urgent need to develop rational combination therapies to enhance response rates to immunotherapy in SCLC. Identification of predictive biomarkers for patient stratification, identifying effective combinations to overcome adaptive resistance to DDR-targeted therapies and identifying strategies to enhance response to immunotherapy are areas of active investigation in SCLC.
Objective:
Determine the maximum tolerated dose (MTD) and recommended phase II dose (RP2D) of veliparib combined with carboplatin and gemcitabine in patients with advanced ovarian cancer and other nonhematologic malignancies.
Methods:
In this phase I study, patients with metastatic or unresectable solid tumors and ≤2 prior chemotherapy regimens received veliparib combined with carboplatin area under the curve (AUC) 4 on day 1 and gemcitabine 800mg/m2 on days 1 and 8 of a 21-day cycle for maximum 10cycles, followed by optional veliparib maintenance therapy. Veliparib dosing commenced twice-daily (BID) continuously on day 1 of cycle 2; granulocyte colony-stimulating factor was permitted. Dose escalation used a Bayesian continual reassessment method. Safety, tolerability, and efficacy were evaluated.
Results:
Seventy-five patients were enrolled (ovarian cancer, n=54; breast cancer, n=12). Thirty-six patients with ovarian cancer (67%) had known germline BRCA mutations. Most common treatment-related adverse events (TRAEs; ≥60%) were thrombocytopenia, neutropenia, nausea, and anemia. Most common grade 3/4 TRAEs (≥40%) were neutropenia and thrombocytopenia. Dose-limiting toxicities were thrombocytopenia and neutropenia. The MTD/RP2D was established at veliparib 250mg with carboplatin AUC 4 plus gemcitabine 800mg/m2. Responses were observed in 69% of patients with BRCA-deficient ovarian cancer (45% partial, 24% complete responses). Five patients remained on veliparib (80-310mg BID) for >34cycles.
Conclusions:
Veliparib plus carboplatin/gemcitabine is tolerated, with a safety profile similar to carboplatin and gemcitabine alone. Combination therapy demonstrated promising preliminary antitumor activity in platinum-sensitive ovarian cancer patients with germline BRCA mutations. Trial registration ID: NCT01063816.
Purpose:
To determine the dose limiting toxicities (DLTs), maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of veliparib in combination with weekly topotecan in patients with solid tumors. Correlative studies were included to assess the impact of topotecan and veliparib on poly(ADP-ribose) levels in peripheral blood mononuclear cells, serum pharmacokinetics of both agents, and potential association of germline repair gene mutations with outcome.
Experimental design:
Eligible patients had metastatic nonhematological malignancies with measurable disease. Using a 3+3 design, patients were treated with veliparib orally twice daily on days 1-3, 8-10 and 15-17 and topotecan intravenously on days 2, 9 and 16 every 28 days. Tumor responses were assessed by RECIST.
Results:
Of 58 patients enrolled, 51 were evaluable for the primary endpoint. The MTD and RP2D was veliparib 300 mg twice daily on days 1-3, 8-10 and 15-17 along with topotecan 3 mg/m2 on days 2, 9 and 16 of a 28-day cycle. DLTs were grade 4 neutropenia lasting >5 days. The median number of cycles was 2 (1-26). The objective response rate was 10%, with 1 complete and 4 partial responses. 22 patients (42%) had stable disease ranging from 4 to 26 cycles. Patients with germline BRCA1, BRCA2 or RAD51D mutations remained on study longer than those without homologous recombination repair (HRR) gene mutations (median 4 vs. 2 cycles).
Conclusions:
Weekly topotecan in combination with veliparib has a manageable safety profile and appears to warrant further investigation.
This corrects the article DOI: 10.1038/nrc.2017.87.
Small-cell lung cancer (SCLC) is a deadly tumour accounting for approximately 15% of lung cancers and is pathologically, molecularly, biologically and clinically very different from other lung cancers. While the majority of tumours express a neuroendocrine programme (integrating neural and endocrine properties), an important subset of tumours have low or absent expression of this programme. The probable initiating molecular events are inactivation of TP53 and RB1, as well as frequent disruption of several signalling networks, including Notch signalling. SCLC, when diagnosed, is usually widely metastatic and initially responds to cytotoxic therapy but nearly always rapidly relapses with resistance to further therapies. There were no important therapeutic clinical advances for 30 years, leading SCLC to be designated a 'recalcitrant cancer'. Scientific studies are hampered by a lack of tissue availability. However, over the past 5 years, there has been a worldwide resurgence of studies on SCLC, including comprehensive molecular analyses, the development of relevant genetically engineered mouse models and the establishment of patient-derived xenografts. These studies have led to the discovery of new potential therapeutic vulnerabilities for SCLC and therefore to new clinical trials. Thus, while the past has been bleak, the future offers greater promise.
SCLC accounts for 15% of lung cancer worldwide. Characterised by early dissemination and rapid development of chemo-resistant disease, less than 5% of patients survive 5 years. Despite 3 decades of clinical trials there has been no change to the standard platinum and etoposide regimen for first line treatment developed in the 1970’s.
The exceptionally high number of genomic aberrations observed in SCLC combined with the characteristic rapid cellular proliferation results in accumulation of DNA damage and genomic instability. To flourish in this precarious genomic context, SCLC cells are reliant on functional DNA damage repair pathways and cell cycle checkpoints.
Current cytotoxic drugs and radiotherapy treatments for SCLC have long been known to act by induction of DNA damage and the response of cancer cells to such damage determines treatment efficacy. Recent years have witnessed improved understanding of strategies to exploit DNA damage and repair mechanisms in order to increase treatment efficacy.
This review will summarise the rationale to target DNA damage response in SCLC, the progress made in evaluating novel DDR inhibitors and highlight various ongoing challenges for their clinical development in this disease.
Purpose:
We aimed to establish the maximum tolerated dose (MTD) of the poly (ADP-ribose) (PAR) polymerase inhibitor, veliparib, in combination with carboplatin in germline BRCA1-?and BRCA2-(BRCA)-associated metastatic breast cancer (MBC), to assess the efficacy of single-agent veliparib, and of the combination treatment post-progression, and to correlate PAR levels with clinical outcome.?
Experimental Design:Phase I patients received carboplatin (AUC of 5-6, every 21 days), with escalating doses of oral twice-daily (BID) veliparib. In a companion phase II trial, patients received single-agent veliparib (400 mg BID) and upon progression, received the combination at MTD. Peripheral blood mononuclear cell PAR and serum veliparib levels were assessed and correlated with outcome.?
Results:Twenty-seven phase I trial patients were evaluable. Dose-limiting toxicities were nausea, dehydration, and thrombocytopenia (MTD: veliparib 150 mg po BID and carboplatin [AUC of 5]). Response rate (RR) was 56%; 3 patients remain in complete response (CR) beyond 3 years. Progression-free (PFS) and overall survival (OS) were 8.7 and 18.8 months. The PFS and OS were 5.2 and 14.5 months in the 44 phase II trial patients, with a 14% RR in BRCA1 (n=22) and 36% in BRCA2 (n=22). One of 30 patients responded to the combination therapy after progression on veliparib. Higher baseline PAR was associated with clinical benefit.
Conclusions:Safety and efficacy are encouraging with veliparib alone and in combination with carboplatin in BRCA-associated MBC. Lasting CRs were observed when the combination was administered first in the phase I trial. Further investigation of PAR level association with clinical outcomes is warranted.
Small cell lung cancer is initially highly responsive to cisplatin and etoposide but in almost every case becomes rapidly chemoresistant, leading to death within 1 year. We modeled acquired chemoresistance in vivo using a series of patient-derived xenografts to generate paired chemosensitive and chemoresistant cancers. Multiple chemoresistant models demonstrated suppression of SLFN11, a factor implicated in DNA-damage repair deficiency. In vivo silencing of SLFN11 was associated with marked deposition of H3K27me3, a histone modification placed by EZH2, within the gene body of SLFN11, inducing local chromatin condensation and gene silencing. Inclusion of an EZH2 inhibitor with standard cytotoxic therapies prevented emergence of acquired resistance and augmented chemotherapeutic efficacy in both chemosensitive and chemoresistant models of small cell lung cancer.
Purpose
Considering promising results in phase II studies, a randomized phase III trial was designed to assess the efficacy of adding bevacizumab to first-line cisplatin plus etoposide for treatment of extensive-disease (ED) small-cell lung cancer (SCLC).
Patients and Methods
Treatment-naive patients with ED-SCLC were randomly assigned to receive either cisplatin plus etoposide (arm A) or the same regimen with bevacizumab (arm B) for a maximum of six courses. In the absence of progression, patients in arm B continued bevacizumab alone until disease progression or for a maximum of 18 courses. The primary end point was overall survival (OS).
Results
Two hundred four patients were randomly assigned and considered in intent-to-treat analyses (103 patients in arm A and 101 patients in arm B). At a median follow-up of 34.9 months in arm A and arm B, median OS times were 8.9 and 9.8 months, and 1-year survival rates were 25% and 37% (hazard ratio, 0.78; 95% CI, 0.58 to 1.06; P = .113), respectively. A statistically significant effect of bevacizumab on OS in patients who received maintenance was seen (hazard ratio, 0.60; 95% CI, 0.40 to 0.91; P = .011). Median progression-free survival times were 5.7 and 6.7 months in arm A and arm B, respectively ( P = .030). Regarding hematologic toxicity, no statistically significant differences were observed; for nonhematologic toxicity, only hypertension was more frequent in arm B (grade 3 or 4, 1.0% v 6.3% in arms A v B, respectively; P = .057).
Conclusion
The addition of bevacizumab to cisplatin and etoposide in the first-line treatment of ED-SCLC had an acceptable toxicity profile and led to a statistically significant improvement in progression-free survival, which, however, did not translate into a statistically significant increase in OS. Further research with novel antiangiogenic agents, particularly in the maintenance setting, is warranted.
High expression levels of SLFN11 correlate with the sensitivity of human cancer cells to DNA-damaging agents. However, little is known about the underlying mechanism. Here, we show that SLFN11 interacts directly with RPA1 and is recruited to sites of DNA damage in an RPA1-dependent manner. Furthermore, we establish that SLFN11 inhibits checkpoint maintenance and homologous recombination repair by promoting the destabilization of the RPA-ssDNA complex, thereby sensitizing cancer cell lines expressing high endogenous levels of SLFN11 to DNA-damaging agents. Finally, we demonstrate that the RPA1-binding ability of SLFN11 is required for its function in the DNA damage response. Our findings not only provide novel insight into the molecular mechanisms underlying the drug sensitivity of cancer cell lines expressing SLFN11 at high levels, but also suggest that SLFN11 expression can serve as a biomarker to predict responses to DNA-damaging therapeutic agents.
Purpose:
The American College of Chest Physicians (ACCP) produced an evidence-based guideline on treatment of patients with small-cell lung cancer (SCLC). Because of the relevance of this guideline to American Society of Clinical Oncology (ASCO) membership, ASCO reviewed the guideline, applying a set of procedures and policies used to critically examine guidelines developed by other organizations.
Methods:
The ACCP guideline on the treatment of SCLC was reviewed for developmental rigor by methodologists. An ASCO Endorsement Panel updated the literature search, reviewed the content, and considered additional recommendations.
Results:
The ASCO Endorsement Panel determined that the recommendations from the ACCP guideline, published in 2013, are clear, thorough, and based on current scientific evidence. ASCO endorses the ACCP guideline on the treatment of SCLC, with the addition of qualifying statements.
Recommendations:
Surgery is indicated for selected stage I SCLC. Limited-stage disease should be treated with concurrent chemoradiotherapy in patients with good performance status. Thoracic radiotherapy should be administered early in the course of treatment, preferably beginning with cycle one or two of chemotherapy. Chemotherapy should consist of four cycles of a platinum agent and etoposide. Extensive-stage disease should be treated primarily with chemotherapy consisting of a platinum agent plus etoposide or irinotecan. Prophylactic cranial irradiation prolongs survival in patients with limited-stage disease who achieve a complete or partial response to initial therapy and may do so in similarly responding patients with extensive-stage disease as well. Additional information is available at http://www.asco.org/endorsements/sclc and http://www.asco.org/guidelineswiki.
Poly (ADP-ribose) polymerases (PARP1, -2 and -3) play important roles in DNA damage repair. As such, a number of PARP inhibitors are undergoing clinical development as anti-cancer therapies, particularly in tumors with DNA repair deficits and in combination with DNA damaging agents. Pre-clinical evidence indicates that PARP inhibitors potentiate the cytotoxicity of DNA alkylating agents. It has been proposed that a major mechanism underlying this activity is the allosteric trapping of PARP1 at DNA single-strand breaks during base excision repair; however, direct evidence of allostery has not been reported. Here the data reveal that veliparib, olaparib, niraparib and talazoparib (BMN-673) potentiate the cytotoxicity of alkylating agents. Consistent with this, all four drugs possess PARP1 trapping activity. Using biochemical and cellular approaches, we directly probe the trapping mechanism for an allosteric component. These studies indicate that trapping is due to catalytic inhibition and not allostery. The potency of PARP inhibitors with respect to trapping and catalytic inhibition is linearly correlated in biochemical systems but is non-linear in cells. High-content imaging of gammaH2Ax levels suggests that this is attributable to differential potentiation of DNA damage in cells. Trapping potency is inversely correlated with tolerability when PARP inhibitors are combined with temozolomide in mouse xenograft studies. As a result, PARP inhibitors with dramatically different trapping potencies elicit comparable in vivo efficacy at maximum tolerated doses. Finally, the impact of trapping on tolerability and efficacy is likely to be context specific.
Understanding the context-specific relationships of trapping and catalytic inhibition with both tolerability and efficacy will aid in determining the suitability of a PARP inhibitor for inclusion in a particular clinical regimen.
Copyright © 2015, American Association for Cancer Research.
Veliparib (V) potentiated therapeutic efficacy of cisplatin (C) and etoposide (E) in preclinical models of SCLC. We conducted this phase 1 study to establish the safety of the combination in human subjects.
The study employed the 3+3 dose escalation design to establish the safety and recommended phase 2 dose (RP2D) of V when combined with fixed doses of C (75mg/m(2) on day 1) and E (100mg/m(2) on days 1-3) in a 21-day cycle. The starting dose of V was 60mg (bid days 1-7) with plan to escalate to 100mg (days 1-7) or de-escalate to 40mg (days 1-7) depending on the dose limiting toxicity (DLT) experience during cycle 1. Patients with treatment-naïve, extensive stage SCLC were included.
The study enrolled 9 patients: M/F (4/5); median age (60); White/African American (8/1). V was tolerated at the 60mg (DLT in 0 of 3 patients) and 100mg dose (DLT in 1 of 6 patients; grade 5 cardiac failure). Veliparib at 100mg in combination with standard doses of C and E was established as the RP2D. Grades 3-5 adverse events irrespective of attribution during cycle 1 included: dehydration (1), diarrhea (1), fatigue (1), febrile neutropenia (1), heart failure (1), leukopenia (6), lymphopenia (1), nausea (2), neutropenia (8), respiratory failure (1), and thrombocytopenia (2). Investigator-assessed efficacy outcome in 7 evaluable patients were stable disease in 2/7 (28.6%), partial response in 4/7 (57.1%), and complete response in 1/7 (14.3%) patients.
This study demonstrated the safety of combining veliparib with cisplatin and etoposide in previously untreated SCLC patients.
Copyright © 2015. Published by Elsevier Ireland Ltd.
Unlabelled:
Small cell lung cancer (SCLC) is an aggressive malignancy distinct from non-small cell lung cancer (NSCLC) in its metastatic potential and treatment response. Using an integrative proteomic and transcriptomic analysis, we investigated molecular differences contributing to the distinct clinical behavior of SCLCs and NSCLCs. SCLCs showed lower levels of several receptor tyrosine kinases and decreased activation of phosphoinositide 3-kinase (PI3K) and Ras/mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase (MEK) pathways but significantly increased levels of E2F1-regulated factors including enhancer of zeste homolog 2 (EZH2), thymidylate synthase, apoptosis mediators, and DNA repair proteins. In addition, PARP1, a DNA repair protein and E2F1 co-activator, was highly expressed at the mRNA and protein levels in SCLCs. SCLC growth was inhibited by PARP1 and EZH2 knockdown. Furthermore, SCLC was significantly more sensitive to PARP inhibitors than were NSCLCs, and PARP inhibition downregulated key components of the DNA repair machinery and enhanced the efficacy of chemotherapy.
Significance:
SCLC is a highly lethal cancer with a 5-year survival rate of less than 10%. To date, no molecularly targeted agents have prolonged survival in patients with SCLCs. As a step toward identifying new targets, we systematically profiled SCLCs with a focus on therapeutically relevant signaling pathways. Our data reveal fundamental differences in the patterns of pathway activation in SCLCs and NSCLCs and identify several potential therapeutic targets for SCLCs, including PARP1 and EZH2. On the basis of these results, clinical studies evaluating PARP and EZH2 inhibition, together with chemotherapy or other agents, warrant further investigation.
Poly(ADP-ribose) polymerase (PARP) is an attractive antitumor target because of its vital role in DNA repair. The homologous recombination (HR) DNA repair pathway is critical for the repair of DNA double-strand breaks and HR deficiency leads to a dependency on error-prone DNA repair mechanisms, with consequent genomic instability and oncogenesis. Tumor-specific HR defects may be exploited through a synthetic lethal approach for the application of anticancer therapeutics, including PARP inhibitors. This theory proposes that targeting genetically defective tumor cells with a specific molecular therapy that inhibits its synthetic lethal gene partner should result in selective tumor cell killing. The demonstration of single-agent antitumor activity and the wide therapeutic index of PARP inhibitors in BRCA1 and BRCA2 mutation carriers with advanced cancers provide strong evidence for the clinical application of this approach. Emerging data also indicate that PARP inhibitors may be effective in sporadic cancers bearing HR defects, supporting a substantially wider role for PARP inhibitors. Drugs targeting this enzyme are now in pivotal clinical trials in patients with sporadic cancers. In this article, the evidence supporting this antitumor synthetic lethal strategy with PARP inhibitors is reviewed, evolving resistance mechanisms and potential molecular predictive biomarker assays are discussed, and the future development of these agents is envisioned.
Poly(ADP-ribosyl)ation is an immediate DNA-damage-dependent post-translational modification of histones and other nuclear proteins that contributes to the survival of injured proliferating cells. Poly(ADP-ribose) polymerases (PARPs) now constitute a large family of 18 proteins, encoded by different genes and displaying a conserved catalytic domain in which PARP-1 (113 kDa), the founding member, and PARP-2 (62 kDa) are so far the sole enzymes whose catalytic activity has been shown to be immediately stimulated by DNA strand breaks. A large repertoire of sequences encoding novel PARPs now extends considerably the field of poly(ADP-ribosyl)ation reactions to various aspects of the cell biology including cell proliferation and cell death. Some of these new members interact with each other, share common partners and common subcellular localizations suggesting possible fine tuning in the regulation of this post-translational modification of proteins. This review summarizes our present knowledge of this emerging superfamily, which might ultimately improve pharmacological strategies to enhance both antitumor efficacy and the treatment of a number of inflammatory and neurodegenerative disorders. A provisional nomenclature is proposed.
To evaluate the preclinical pharmacokinetics and antitumor efficacy of a novel orally bioavailable poly(ADP-ribose) polymerase (PARP) inhibitor, ABT-888.
In vitro potency was determined in a PARP-1 and PARP-2 enzyme assay. In vivo efficacy was evaluated in syngeneic and xenograft models in combination with temozolomide, platinums, cyclophosphamide, and ionizing radiation.
ABT-888 is a potent inhibitor of both PARP-1 and PARP-2 with K(i)s of 5.2 and 2.9 nmol/L, respectively. The compound has good oral bioavailability and crosses the blood-brain barrier. ABT-888 strongly potentiated temozolomide in the B16F10 s.c. murine melanoma model. PARP inhibition dramatically increased the efficacy of temozolomide at ABT-888 doses as low as 3.1 mg/kg/d and a maximal efficacy achieved at 25 mg/kg/d. In the 9L orthotopic rat glioma model, temozolomide alone exhibited minimal efficacy, whereas ABT-888, when combined with temozolomide, significantly slowed tumor progression. In the MX-1 breast xenograft model (BRCA1 deletion and BRCA2 mutation), ABT-888 potentiated cisplatin, carboplatin, and cyclophosphamide, causing regression of established tumors, whereas with comparable doses of cytotoxic agents alone, only modest tumor inhibition was exhibited. Finally, ABT-888 potentiated radiation (2 Gy/d x 10) in an HCT-116 colon carcinoma model. In each model, ABT-888 did not display single-agent activity.
ABT-888 is a potent inhibitor of PARP, has good oral bioavailability, can cross the blood-brain barrier, and potentiates temozolomide, platinums, cyclophosphamide, and radiation in syngeneic and xenograft tumor models. This broad spectrum of chemopotentiation and radiopotentiation makes this compound an attractive candidate for clinical evaluation.
Extensive-disease small cell lung cancer (ED SCLC) is characterized by initial chemosensitivity, followed inevitably by relapse. The optimal role of additional chemotherapy at the time of progression is controversial. We reviewed the experience of all patients over a 5-year period with ED SCLC to describe outcomes of second-line chemotherapy.
Records of all patients registered at The Ottawa Hospital Regional Cancer Centre with ED SCLC were reviewed, and baseline prognostic factors, chemotherapy delivered, and treatment outcomes were extracted. Multivariate analyses were performed to determine the effect of second-line chemotherapy on survival.
Of 192 patients who completed first-line chemotherapy, only 62 (32%) received second-line therapy; these patients were younger and fitter, and lived longer from the time of relapse (5.2 vs. 1.5 months). Second-line therapy was an independent predictor of survival. Benefit was observed in patients with relapse either before or after 60 days from the completion of first-line therapy.
Second-line chemotherapy given at the time of relapse of ED SCLC seems to be associated with prolongation of survival, even in patients traditionally felt to have chemoresistant disease. The majority of patients, however, do not receive second-line therapy because of poor clinical status at relapse.
ESMO Minimum Clinical Recommendations for diagnosis, treatment and follow-up of small-cell lung cancer (SCLC)
- ESMO
Niraparib and temozolomide in treating patients with extensive-stage small-cell lung cancer with a complete or partial response to platinumbased first-line chemotherapy. Identifier NCT03830918. Bethesda (MD): National Library of Medicine (US)
- Clinicaltrials
- Gov
ClinicalTrials.gov. Niraparib and temozolomide in treating patients with extensive-stage small-cell lung cancer with a complete or partial response to platinumbased first-line chemotherapy. Identifier NCT03830918. Bethesda (MD):
National Library of Medicine (US); 2019. Available from: https://clinicaltrials.
gov/ct2/show/NCT03830918.
Study of olaparib and temozolomide in patients with recurrent small-cell lung cancer following failure of prior chemotherapy. Identifier NCT02446704. Bethesda (MD): National Library of Medicine (US)
- Clinicaltrials
- Gov
ClinicalTrials.gov. Study of olaparib and temozolomide in patients with recurrent small-cell lung cancer following failure of prior chemotherapy. Identifier
NCT02446704. Bethesda (MD): National Library of Medicine (US); 2015.
Available from: https://clinicaltrials.gov/ct2/show/NCT02446704.
Talazoparib and low-dose temozolomide in treating participants with relapsed or refractory extensive-stage small-cell lung cancer. Bethesda (MD): National Library of Medicine (US); Identifier NCT03672773
- Clinicaltrials
- Gov
ClinicalTrials.gov. Talazoparib and low-dose temozolomide in treating participants with relapsed or refractory extensive-stage small-cell lung cancer. Bethesda
(MD): National Library of Medicine (US); Identifier NCT03672773. 2018.
Available from: https://clinicaltrials.gov/ct2/show/NCT03672773.