Pamela J Goodwin's research while affiliated with Mount Sinai Hospital, Toronto and other places

Background: The presence of tumor cells (or their components) in the blood of women with a history of early breast cancer has the potential to herald the development of metastatic recurrence at its earliest stages. Such early detection could potentially lead to novel prevention strategies, but it requires a sensitive assay. Objective: To use the Epic Sciences platform to detect and enumerate CTCs in blood samples from patients with an established diagnosis of metastatic breast cancer (MBC), prior to initiation of 1st line systemic therapy in the metastatic setting. Methods: We conducted a multi-center prospective cohort study to evaluate the presence of CTCs using the Epic Sciences platform among patients with a new diagnosis of MBC. Men or women age 18 to 85 were included, irrespective of breast cancer subtype. Patients with a prior or concurrent malignancy whose natural history or treatment had the potential to interfere with the detection of MBC in a liquid biopsy were excluded. A one-time blood draw was performed before patients received any local or systemic therapy in the metastatic setting. In addition, those with recurrent disease must have been off any systemic adjuvant therapy for ≥3 weeks prior to blood collection. Two 5 mL blood samples were obtained for CTC identification and enumeration. CTC identification was based on immunofluorescence analysis using Epic Sciences platform as previously described (Ueno et al 2017). The presence of CTCs was correlated with clinical and pathological features, which were abstracted from medical records and pathology reports. The association between the presence of CTCs and clinical/pathologic characteristics was tested using Fisher’s exact test for categorical variables and t-test or Wilcoxon rank sum tests for numerical variables. All analyses were performed using the R software package. Results: 100 patients were recruited between February 2021 and January 2023 at five academic oncology centres in Ontario and Quebec, Canada. 95 patients had evaluable blood for analysis and 5 did not due to blood age and/or insufficient blood volume. Six patients were excluded after providing a blood sample because tissue biopsy ultimately revealed a 2nd primary tumor (n=4) or benign tissue (n=2). Hence, 89 patients with a clinical diagnosis of MBC and with evaluable blood for CTC analyses were ultimately included in our cohort. The average age of patients was 61 years. Most patients (n=49, 55%) had a prior history of early breast cancer, 38 (43%) had de-novo metastatic disease and prior breast cancer history was unknown for 2 patients. 50 (66%) of patients had visceral metastatic disease. The most common sites of metastases included bone (62%), lung (30%), liver (29%) and lymph nodes (17%). 63 of 89 patients (71%) had detectable CTCs at baseline, prior to any local or systemic treatment in the metastatic setting. The median number of detectable CTCs per 5mL sample was 2 (IQR 8.5) and the range was 0 – 12,798. Twenty nine of 89 (33%) patients had 5 or more CTCs detected per 5ml blood. The proportion of patients with detectable CTCs was numerically highest (n=39/51, 76%) among patients with hormone receptor (HR)+/HER2-ve breast cancer, followed by HER2+ (n=16/22, 73%) and triple negative (n=8/13, 62%) disease. Associations between CTC detection with prior history of early breast cancer, sites of metastatic disease and disease burden will also be presented. Conclusions: Approximately 3 in 4 women with newly diagnosed metastatic breast cancer have detectable CTCs using the Epic Sciences platform prior to initiation of first line systemic therapy. CTCs may be a promising tool for the monitoring of breast cancer recurrence and will be investigated in an ongoing Canadian prospective observational study that aims to elucidate biomarkers of late breast cancer recurrence. Citation Format: Katarzyna Jerzak, Pamela Goodwin, Marguerite Ennis, Christine Brezden-Masley, Nathaniel Bouganim, Mark Basik, Arushi Jain, Giuseppe Di Caro, Rick Wenstrup, Nadine Hartmann, Megan Slade, Ana Elisa Lohmann. A multi-center prospective cohort study to evaluate the presence of circulating tumor cells using the Epic Sciences platform among women with metastatic breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-15-01.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned coprimary or secondary analyses are not yet available. Clinical trial updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported. Metformin has been associated with lower cancer risk in epidemiologic and preclinical research. In the MA.32 randomized adjuvant breast cancer trial, metformin ( v placebo) did not affect invasive disease-free or overall survival. Here, we report metformin effects on the risk of new cancer. Between 2010 and 2013, 3,649 patients with breast cancer younger than 75 years without diabetes with high-risk T1-3, N0-3 M0 breast cancer (any estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2) were randomly assigned to metformin 850 mg orally twice a day or placebo twice a day for 5 years. New primary invasive cancers (outside the ipsilateral breast) developing as a first event were identified. Time to events was described by the competing risks method; two-sided likelihood ratio tests adjusting for age, BMI, smoking, and alcohol intake were used to compare metformin versus placebo arms. A total of 184 patients developed new invasive cancers: 102 metformin and 82 placebo, hazard ratio (HR), 1.25; 95% CI, 0.94 to 1.68; P = .13. These included 48 contralateral invasive breast cancers (27 metformin v 21 placebo), HR, 1.29; 95% CI, 0.72 to 2.27; P = .40 and 136 new nonbreast primary cancers (75 metformin v 61 placebo), HR, 1.24; 95% CI, 0.88 to 1.74; P = .21. Metformin did not reduce the risk of new cancer development in these nondiabetic patients with breast cancer.

12001 Background: Obesity is a poor prognostic factor in early breast cancer. The Breast Cancer Weight Loss (BWEL) trial (Alliance for Clinical Trials in Oncology A011401; NCT02750826) evaluates the impact of a WLI on invasive disease-free survival in breast cancer patients (pts) with a body mass index (BMI) ³27 kg/m ² . Here we report the impact of the WLI on weight change. Methods: Eligible pts were within 14 months of diagnosis of stage 2-3 HER2-negative breast cancer, had completed chemotherapy and radiation (if administered), and were randomized 1:1 to a telephone-based WLI plus health education (HE) or an HE alone control group. The WLI was delivered by telephone-based health coaching and focused on caloric restriction and increased exercise. Height and weight were measured at baseline and 12 months. Changes in weight were compared between groups. Analysis was performed with univariable and multivariable (including arm, baseline weight, menopausal status, race/ethnicity, and hormone receptor [HR] status) regression models. A 0.05 level of significance was used. Results: 3181 women were randomized between 8/2016 and 2/2021. At baseline, mean BMI was 34.5 (±5.74) kg/m ² , mean age was 53.4 (±10.58) years, and 57% of pts were postmenopausal at the time of diagnosis. 80.3% of participants were White, 12.8% were Black, and 7.3% were Hispanic. Follow-up weight was available from 2293 pts alive and disease-free at 12 months. The WLI led to a significant decrease in weight relative to controls; pts randomized to WLI lost an average of 4.8% (±7.9) of baseline body weight at 12 months vs. 0.8% (± 6.4) weight gain in controls (p<0.0001). Pts randomized to WLI experienced significant weight loss (vs controls) across demographic and tumor factors (Table). WLI effect differed significantly by menopausal status (interaction p value = 0.0057) and race/ethnicity (interaction p-value = 0.019), but not HR status (interaction p-value = 0.17). Conclusions: A telephone-based WLI induced significant, clinically meaningful weight loss in breast cancer pts with overweight and obesity across demographic and tumor factors. Additional tailoring of the WLI could be useful to enhance weight loss in Black and younger pts. Further follow-up of the BWEL trial will evaluate whether the WLI improves disease outcomes. Support: U10CA180821, U10CA180882, UG1CA189823; https://acknowledgments.alliancefound.org . Clinical trial information: NCT02750826 . [Table: see text]

1028 Background: Tissue biopsy is recommended to confirm breast cancer (BC) recurrence. Liquid biopsy [including circulating tumour cells (CTCs) and circulating tumour DNA (ctDNA)] is a non-invasive approach for detecting cancer that may provide information to identify treatment choices and replace invasive biopsies. This ongoing study aims to assess the concordance between tissue and liquid biopsy testing in subjects presenting with suspicion of distant recurrence from BC. Methods: Patients with suspected metastatic BC were enrolled; tumour characteristics and treatment were recorded. Blood samples were collected within 30 days before tissue biopsy, or within 7-28 days after tissue biopsy and before any systemic or radiation treatment. Samples were shipped to EPIC Sciences and processed within 96 hours; after plasma isolation, nucleated cells were plated; slides and plasma were banked. CTCs were identified using Epic Sciences digital imaging and machine learning algorithms. Single-cell isolation for genomic ctDNA analysis was performed. Cell free DNA was analyzed using a validated NGS panel to detect ctDNA alterations. The presence of metastases was classified as suspicious, highly suspicious, definitely metastatic BC or other by the treating oncologist based on the patient's clinical presentation and biopsy pathology results. Epic Sciences classified samples into similar categories based on CTC and ctDNA assay results. These classifications were performed independently. Sensitivity of the Epic Sciences methodology to detect metastatic BC (as determined by the treating oncologist), and its false positive rate were calculated. Results: 100 patients were enrolled from June 2020 to October 2022; shipping delays precluded EPIC assays in six patients; 94 patients were analyzed. Of 83 cases deemed suspicious, highly suspicious, or definitely metastatic BC by the treating oncologist, 61 were also deemed so by Epic Sciences (sensitivity of 73.5%, 95% confidence interval, CI 63.1% - 81.9%). Of 66 cases assigned as suspicious, highly suspicious, or definitely metastatic BC by the Epic Sciences, 4 had new primary cancers (3 lung cancer, 1 hepatocarcinoma), for a false positive rate of 6.1% (95% CI 1.9% - 15.0%). One additional case was classified as un-specified adenocarcinoma (possibly breast) by the treating oncologist; resolution awaits further follow-up. Conclusions: Preliminary results show that 73.5% of distant BC recurrences were correctly identified by liquid biopsy. A small number of false positive results occurred in patients with other new primary cancers. Additional analyses with CTC characterization are ongoing. [Table: see text]

Background: The MA32 study investigated whether 5 years of metformin (versus placebo) improves invasive disease-free survival in early-stage breast cancer (BC). Non-adherence to endocrine therapy (ET) and medications for chronic conditions is common and increases with drug toxicity and polypharmacy. This secondary analysis evaluates rates and predictors of early discontinuation of metformin, placebo, and ET among participants with HR-positive BC. Methods: Patients with high-risk non-metastatic BC were randomized to 60 months of metformin (850 mg BID) or placebo BID. Patients were administered bottles of metformin/placebo every 180 days. Metformin/placebo adherence was defined as a bottle dispensed at month 48 or later. The ET adherence analysis included patients with HR-positive BC who received ET with start and stop date reported, with adherence defined as > 48 months of use. Associations of covariates with study drug and ET adherence were examined using multivariable models. Results: Among the 2521 HR-positive BC patients, 32.9% were non-adherent to study drug. Non-adherence was higher among patients on metformin vs placebo (37.1% vs 28.7%, p < 0.001). Reassuringly, ET discontinuation rates were similar between treatment arms (28.4% vs 28.0%, p = 0.86). Patients who were non-adherent to ET were more likely to discontinue study therapy (38.8% vs 30.1%, p < 0.0001). In a multivariable analysis, study drug non-adherence was increased with metformin vs placebo (OR: 1.50, 95% CI 1.25-1.80; p < 0.0001); non-adherence to ET (OR: 1.47, 95% CI 1.20-1.79, p < 0.0001); grade 1 or greater GI toxicity during the first 2 years; lower age; and higher body mass index. Conclusion: While non-adherence was higher among patients on metformin, it was still considerable among patients on placebo. Reassuringly, treatment arm allocation did not impact ET adherence. Attention to global medication adherence is needed to improve BC and non-oncological outcomes in cancer survivors. Trial registration: ClinicalTrials.gov: NCT01.

526 Background: The MA32 study (NCT01101438) investigated whether 5-years of metformin improves invasive disease-free survival in early-stage breast cancer (BC). Non-adherence to endocrine therapy (ET) and medications for chronic conditions is common, and increases with drug toxicity and polypharmacy. This secondary analysis evaluates rates and predictors of early discontinuation of metformin, placebo, and ET among participants with HR positive BC. Methods: Patients with high-risk non-metastatic BC were randomized to 60 months of metformin (850 mg BID) or placebo. Patients were administered bottles of metformin/placebo every 180 days. Metformin/placebo compliance was defined as a bottle dispensed at month 48 or later (i.e., medication supplied for 54 months). The ET compliance analysis included patients with HR positive BC who received adjuvant ET with start and stop date reported and was defined as > 48 months of use. Associations of baseline covariates with drug compliance and with ET adherence were examined using multivariable models. Results: Among the 2,521 HR-positive BC patients, 32.9% were non-compliant to study drug. Non-compliance was higher among patients on metformin vs. placebo (37.1% vs. 28.7%, p<0.001). Reassuringly, compliance to ET was similar between treatment arms (28.4% vs 28.0%, p=0.86). Patients who were non-compliant to endocrine therapy, were more likely to be non-compliant to study therapy (38.8% vs. 30.1%, p<0.0001). In a multivariable analysis, study drug non-compliance was increased with metformin vs. placebo (OR=1.43, 95% CI, 1.21-1.70; p<0.0001); grade 1 or greater GI toxicity during the first year (70.9% vs. 53.2%; OR=1.20, 95% CI, 1.01-1.44; p=0.044); lower age (age < 50 OR = 1.44, 95% CI, 1.21 – 1.71; p<0.01) and higher body mass index (BMI > 30, OR=1.49, 95% CI, 1.25 - 1.77; p<0.0001). Study drug non-compliance was decreased with prior receipt of chemotherapy (OR = 0.68, 95% CI, 0.50–0.84; p<0.001). Non-compliance with endocrine therapy was associated with increased non-compliance to study drug (OR: 1.47, 95% CI, 1.20, 1.70, p < 0.0001). Study drug (metformin vs placebo) non-compliance was not associated with endocrine therapy non-compliance (OR=0.97, 95% CI, 0.80-1.17; p=0.74). Conclusions: While non-compliance was higher among patients on metformin, it was still considerable among patients on placebo. Among other factors, development of GI toxicity and non-adherence to ET were associated with non-adherence to study drug. Many BC patients on ET are prescribed metformin and other oral medications for the treatment of chronic conditions. Reassuringly, non-adherence to study drug did not impact endocrine therapy adherence. Attention to global medication adherence is needed to improve BC and cardiovascular outcomes in cancer survivors. Clinical trial information: NCT0110143.

Importance: Metformin, a biguanide commonly used to treat type 2 diabetes, has been associated with potential beneficial effects across breast cancer subtypes in observational and preclinical studies. Objective: To determine whether the administration of adjuvant metformin (vs placebo) to patients with breast cancer without diabetes improves outcomes. Design, setting, and participants: MA.32, a phase 3 randomized, placebo-controlled, double-blind trial, conducted in Canada, Switzerland, US, and UK, enrolled 3649 patients with high-risk nonmetastatic breast cancer receiving standard therapy between August 2010 and March 2013, with follow-up to October 2020. Interventions: Patients were randomized (stratified for hormone receptor [estrogen receptor and/or progesterone receptor {ER/PgR}] status, positive vs negative; body mass index, ≤30 vs >30; human epidermal growth factor receptor 2 [ERBB2, formerly HER2 or HER2/neu], positive vs negative; and any vs no chemotherapy) to 850 mg of oral metformin twice a day (n = 1824) or oral placebo twice a day (n = 1825) for 5 years. Main outcomes and measures: The primary outcome was invasive disease-free survival in hormone receptor-positive breast cancer. Of the 8 secondary outcomes, overall survival, distant relapse-free survival, and breast cancer-free interval were analyzed. Results: Of the 3649 randomized patients (mean age, 52.4 years; 3643 women [99.8%]), all (100%) were included in analyses. After a second interim analysis, futility was declared for patients who were ER/PgR-, so the primary analysis was conducted for 2533 patients who were ER/PgR+. The median duration of follow-up in the ER/PgR+ group was 96.2 months (range, 0.2-121 months). Invasive disease-free survival events occurred in 465 patients who were ER/PgR+. The incidence rates for invasive disease-free survival events were 2.78 per 100 patient-years in the metformin group vs 2.74 per 100 patient-years in the placebo group (hazard ratio [HR], 1.01; 95% CI, 0.84-1.21; P = .93), and the incidence rates for death were 1.46 per 100 patient-years in the metformin group vs 1.32 per 100 patient-years in the placebo group (HR, 1.10; 95% CI, 0.86-1.41; P = .47). Among patients who were ER/PgR-, followed up for a median of 94.1 months, incidence of invasive disease-free survival events was 3.58 vs 3.60 per 100 patient-years, respectively (HR, 1.01; 95% CI, 0.79-1.30; P = .92). None of the 3 secondary outcomes analyzed in the ER/PgR+ group had statistically significant differences. Grade 3 nonhematological toxic events occurred more frequently in patients taking metformin than in patients taking placebo (21.5% vs 17.5%, respectively, P = .003). The most common grade 3 or higher adverse events in the metformin vs placebo groups were hypertension (2.4% vs 1.9%), irregular menses (1.5% vs 1.4%), and diarrhea (1.9% vs 7.0%). Conclusions and relevance: Among patients with high-risk operable breast cancer without diabetes, the addition of metformin vs placebo to standard breast cancer treatment did not significantly improve invasive disease-free survival. Trial registration: ClinicalTrials.gov Identifier: NCT01101438.

An interim analysis is commonly used in phase III superiority trials to compare treatment arms, with the goal of terminating exposure of patients to ineffective or unsafe drugs, or to identify highly effective therapies for earlier public disclosure. Traditionally, interim analyses have been designed to identify early evidence of extremely large benefit of the experimental approach, potentially leading to early dissemination of effective treatments. Increasingly, interim analysis has also involved analysis of futility which may lead to early termination of a trial that will not yield additional useful information This presents an important challenge in early-stage hormone receptor positive breast cancer, where recurrence often occurs late, with a steady annual event rate up to 20 years. Early analysis of events may miss late treatment effects that can be observed only with longer follow-up. We discuss approaches to futility analysis in adjuvant clinical trials in hormone receptor positive breast cancer, the role of the Data Safety Monitoring Committee in such analyses, considerations of the potential harms versus benefits of treatment, and the risks of continuing versus early stopping of a trial.

Objectives: Antibody testing against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been instrumental in detecting previous exposures and analyzing vaccine-elicited immune responses. Here, we describe a scalable solution to detect and quantify SARS-CoV-2 antibodies, discriminate between natural infection- and vaccination-induced responses, and assess antibody-mediated inhibition of the spike-angiotensin converting enzyme 2 (ACE2) interaction. Methods: We developed methods and reagents to detect SARS-CoV-2 antibodies by enzyme-linked immunosorbent assay (ELISA). The main assays focus on the parallel detection of immunoglobulin (Ig)Gs against the spike trimer, its receptor binding domain (RBD) and nucleocapsid (N). We automated a surrogate neutralisation (sn)ELISA that measures inhibition of ACE2-spike or -RBD interactions by antibodies. The assays were calibrated to a World Health Organization reference standard. Results: Our single-point IgG-based ELISAs accurately distinguished non-infected and infected individuals. For seroprevalence assessment (in a non-vaccinated cohort), classifying a sample as positive if antibodies were detected for ≥ 2 of the 3 antigens provided the highest specificity. In vaccinated cohorts, increases in anti-spike and -RBD (but not -N) antibodies are observed. We present detailed protocols for serum/plasma or dried blood spots analysis performed manually and on automated platforms. The snELISA can be performed automatically at single points, increasing its scalability. Conclusions: Measuring antibodies to three viral antigens and identify neutralising antibodies capable of disrupting spike-ACE2 interactions in high-throughput enables large-scale analyses of humoral immune responses to SARS-CoV-2 infection and vaccination. The reagents are available to enable scaling up of standardised serological assays, permitting inter-laboratory data comparison and aggregation.