Long term lymphocyte reconstitution after alemtuzumab treatment of multiple sclerosis

Abstract

Alemtuzumab is a lymphocyte depleting monoclonal antibody that has demonstrated superior efficacy over interferon β-1a for relapsing-remitting multiple sclerosis (MS), and is currently under investigation in phase 3 trials. One unresolved issue is the duration and significance of the lymphopenia induced. The long term effects on lymphocyte reconstitution of a single course, and the consequences that this has on disability, morbidity, mortality and autoimmunity, were examined.
The lymphocyte reconstitution (n=36; 384 person years) and crude safety data (n=37; 447 person years) are reported for the first patients with progressive MS to receive alemtuzumab (1991-1997). Reconstitution time was expressed as a geometric mean or, when a non-negligible number of individuals failed to recover, as a median using survival analysis.
Geometric mean recovery time (GMRT) of total lymphocyte counts to the lower limit of the normal range (LLN; ≥1.0×10(9) cells/l) was 12.7 months (95% CI 8.8 to 18.2 months). For B cells, GMRT to LLN (≥0.1×10(9)/l) was 7.1 months (95% CI 5.3 to 9.5); median recovery times for CD8 (LLN ≥0.2×10(9) cells/l) and CD4 lymphocytes (LLN ≥0.4×10(9) cells/l) were 20 months and 35 months, respectively. However, CD8 and CD4 counts recovered to baseline levels in only 30% and 21% of patients, respectively. No infective safety concerns arose during 447 person years of follow-up.
Lymphocyte counts recovered to LLN after a single course of alemtuzumab in approximately 8 months (B cells) and 3 years (T cell subsets), but usually did not recover to baseline values. However, this long lasting lymphopenia in patients with a previously normal immune system was not associated with an increased risk of serious opportunistic infection.

Full text

RESEARCH PAPER
Long term lymphocyte reconstitution after
alemtuzumab treatment of multiple sclerosis
Grant A Hill-Cawthorne,
1,2
Tom Button,
1
Orla Tuohy,
1
Joanne L Jones,
1
Karen May,
1
Jennifer Somerfield,
1,3
Alison Green,
4
Gavin Giovannoni,
5,6
D Alastair S Compston,
1
Michael T Fahey,
7,8
Alasdair J Coles
1
ABSTRACT
Background Alemtuzumab is a lymphocyte depleting
monoclonal antibody that has demonstrated superior
efficacy over interferon
b
-1a for relapsingeremitting
multiple sclerosis (MS), and is currently under
investigation in phase 3 trials. One unresolved issue is
the duration and significance of the lymphopenia
induced. The long term effects on lymphocyte
reconstitution of a single course, and the consequences
that this has on disability, morbidity, mortality and
autoimmunity, were examined.
Methods The lymphocyte reconstitution (n¼36; 384
person years) and crude safety data (n¼37; 447 person
years) are reported for the first patients with progressive
MS to receive alemtuzumab (1991e1997).
Reconstitution time was expressed as a geometric mean
or, when a non-negligible number of individuals failed to
recover, as a median using survival analysis.
Results Geometric mean recovery time (GMRT) of total
lymphocyte counts to the lower limit of the normal range
(LLN; $1.0310
9
cells/l) was 12.7 months (95% CI 8.8
to 18.2 months). For B cells, GMRT to LLN ($0.1310
9
/l)
was 7.1 months (95% CI 5.3 to 9.5); median recovery
times for CD8 (LLN $0.2310
9
cells/l) and CD4
lymphocytes (LLN $0.4310
9
cells/l) were 20 months
and 35 months, respectively. However, CD8 and CD4
counts recovered to baseline levels in only 30% and 21%
of patients, respectively. No infective safety concerns
arose during 447 person years of follow-up.
Conclusions Lymphocyte counts recovered to LLN after
a single course of alemtuzumab in approximately
8 months (B cells) and 3 years (T cell subsets), but
usually did not recover to baseline values. However, this
long lasting lymphopenia in patients with a previously
normal immune system was not associated with an
increased risk of serious opportunistic infection.
INTRODUCTION
Campath-1H is a humanised monoclonal antibody
that binds CD52 and depletes lymphocytes,
monocytes and NK cells.
1
Marketed as alemtu-
zumab, now Lemtrada, it was approved for the
treatment of chronic lymphocytic leukaemia in
2001.
2
Since 1991, we have investigated its use as
a treatment for multiple sclerosis (MS): a phase
2 trial has been published
3
and phase 3 trials are
ongoing.
45
However, despite the potential for its
widespread use in young systemically healthy
adults with MS, the extent and clinical significance
of the lymphopenia that alemtuzumab induces is
not well known. Experience from alemtuzumab
treatment of other conditions is not representative,
as in lymphocytic malignancies there is abnormal
lymphocyte proliferation, and in treatment resis-
tant systemic autoimmune disease, patients are
older, unwell
6
and have been exposed to multiple
immunotherapies.
7
The aim of this study was to describe the long
term safety effects of a single course of alemtu-
zumab in treatment naïve people with MS. We
report data from the first 37 patients, each with
progressive MS, treated between 1991 and 1997.
While alemtuzumab successfully reduced the
relapse, we have previously reported that patients
continued to experience progressive disability.
8
Previously, assuming linear kinetics of reconstitu-
tion after alemtuzumab, data from this cohort led
to estimates of median recovery time to baseline
levels for CD4 and CD8 T cells of 61 and
30 months, respectively, with B cells reaching
baseline levels and ‘overshooting’more rapidly.
9
Linear reconstitution is a reasonable model for the
first 12e18 months but we now show that after
18 months the rate decelerates to a point that
linear kinetics becomes an inappropriate model.
We now re-address the extent of lymphocyte
recovery in this cohort after a longer interval using
analysis techniques that do not assume linear
reconstitution.
We also report the long term safety profile of this
small cohort. We previously reported low rates of
infections in the first few years after alemtuzumab,
strikingly lower than patients with HIV infection
with similar CD4 counts
10
; one potential explana-
tion being that, after alemtuzumab, lymph nodes
retain a substantial number of healthy lympho-
cytes that escape deletion.
11e13
We report the effect
of alemtuzumab on CSF oligoclonal bands (OCB)
in the context of progressive MS. Finally, we
explore the relationship between lymphocyte
reconstitution and the development of secondary
autoimmune diseases: up to 30% of alemtuzumab
treated MS patients develop autoimmune thyroid
disease,
13
and other autoimmune diseases such as
Goodpasture’s disease are also seen.
9
METHODS
This is a review of safety and lymphocyte recon-
stitution of the first 37 patients to receive alem-
tuzumab as a treatment for MS, in Cambridge,
UK.
1
Department of Neurology,
University of Cambridge,
Cambridge, UK
2
Pathogen Genomics
Laboratory, King Abdullah
University of Science and
Technology (KAUST), Thuwal,
Mekkah, Saudi Arabia
3
Department of Medicine,
University of Auckland,
Auckland, New Zealand
4
The National CJD Surveillance
Unit, University of Edinburgh,
Edinburgh, UK
5
Institute of Neurology,
University College London,
London, UK
6
Centre for Neuroscience and
Trauma, Blizard Institute, Barts
and The London School of
Medicine and Dentistry, Queen
Mary University of London,
London, UK
7
Centre for Applied Medical
Statistics, Department of Public
Health and Primary Care,
University of Cambridge,
Cambridge, UK
8
Division of Mathematics,
Informatics and Statistics,
Commonwealth Scientific and
Industrial Research Organisation
(CSIRO), Clayton South, Victoria,
Australia
Correspondence to
Dr A J Coles, Department of
Neurology, Box 165,
Addenbrooke’s Hospital,
Cambridge CB2 2QQ, UK;
ajc1020@medschl.cam.ac.uk
Received 24 June 2011
Revised 22 September 2011
Accepted 23 September 2011
Published Online First
5 November 2011
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Patients and treatment
The first cohort of patients, treated between 1991 and 1993,
consisted of seven patients, six with secondary progressive and
one with primary progressive disease.
14
Six patients were treated
with 12 mg of alemtuzumab daily for 10 days and one patient
received 60 mg in total. Early
14
and later
89
data on efficacy have
been reported previously. Five of the seven patients were re-
treated between 2 and 4 years after the first dose. The second
cohort, treated between 1995 and 1997, consisted of 29 patients,
all with secondary progressive MS.
8
All patients received 100 mg
of alemtuzumab over 5 days. Fourteen of the 29 patients were
also treated with a novel humanised IgG4 anti-CD4 antibody
(200 mg over the subsequent 5 days), which was designed,
successfully, to be non-depleting. For the purposes of analysis,
both cohorts are considered together. No antimicrobial prophy-
laxis was administered to either cohort and no other immuno-
suppressant medications were taken during follow-up. One
additional patient with progressive MS, treated in 1997, is also
included in the analysis of reconstitution. This study was
approved by the local research ethics committees and all patients
gave written informed consent. GAHC, TB and MTF analysed
the data and all authors had access to the primary clinical data.
Assessments
All patients were offered continued follow-up at our site,
3 monthly for the first 3 years after alemtuzumab, then bian-
nually for 2 years, and annually thereafter. At each of these
visits, blood was taken for total lymphocyte count, subsets
(CD4, CD8, CD19), autoantibody screen, liver function and
renal function. Blood tests were variably available between 1990
and 2009 depending on the patient’s treatment date and
availability for follow-up. Disability was assessed annually using
Kurtzke’s Expanded Disability Status Score (EDSS).
15
Eleven
patients, who lived at a distance, declined these assessments.
All living patients were reviewed within the past 2 years or
received a telephone interview. As a minimum, data on auto-
immune disease, major illnesses or death were collected, as well
as a crude estimate of disability. Autoimmunity was defined as
the clinical development of secondary autoimmune disease or
persistently abnormal thyroid function tests in the presence of
autoantibodies indicating thyroid disease, as in our previous
studies.
16
Assessment of recovery
Total lymphocyte counts and subset analyses were carried out
whenever patients attended the clinic. Analysis was restricted to
measurements taken at least 1 day after completing the first
cycle of alemtuzumab and not confounded by any subsequent
treatment. That is, all data recorded after subsequent treatments
were excluded in this analysis. The number of repeated
measurements per patient ranged from 5 to 46 (median 18, IQR
12e23). Four components of immune reconstitution were
examined: total lymphocyte counts, CD19, CD4 and CD8
lymphocyte subsets.
Total and T lymphocyte cell counts were analysed to two
endpoints. The first endpoint was time taken for recovery to
a predefined ‘lower limit of normal’level (LLN). These LLNs
were derived from our laboratory ranges and were 1.0310
9
,
0.4310
9
and 0.2310
9
cells/l for total, CD4 and CD8 lympho-
cytes, respectively. Throughout this manuscript we shall refer to
this endpoint as reconstitution to ‘normal’. The second endpoint
was time to recovery to the patient’s relevant lymphocyte count
before alemtuzumab treatment. This second endpoint will be
referred to as reconstitution to ‘baseline level’.
B lymphocytes were only analysed to the first
endpointdnamely, reconstitution to ‘normal’due to a lack of
baseline measurements. For B lymphocytes, LLN was
0.1310
9
cells/l.
Fifteen patients from the second cohort consented to lumbar
puncture before and after alemtuzumab (table 1). Median
disease duration was 4 years (range 1e13). Unconcentrated CSF
and paired serum samples were assessed using isoelectric
focusing in agarose gel with immunofixation. The blots were
read independently by two experienced observers blinded with
respect to the identity of each patient and the time-point of the
sample.
Statistical analysis
Median and IQR were used to describe data. To make statistical
inference on recovery time for reconstitution, the geometric
mean or median was used. When the number of individuals who
failed to recover was negligible, recovery time was log trans-
formed to improve symmetry and the geometric mean
computed. When there was a non-negligible number of indi-
viduals failing to recover, their recovery times were treated as
censored and a median was estimated using survival analysis.
The relationship with age at baseline and autoimmune status
was examined using a scatterplot for the former and a box and
whisker plot for the latter. To examine the effect of autoim-
munity, a t test of zero mean difference in log recovery time was
calculated. This result was back transformed to the original time
scale and reported as the ratio of the geometric means for
autoimmunity absent divided by autoimmunity present along
with its 95% CI and p value. Median recovery times to baseline
level (as well as to normal level for CD4 and CD8) were esti-
mated using survival analysis to allow inclusion of patients who
did not recover to their baseline level in the analysis. These
results were presented in cumulative incidence (KaplaneMeier)
plots of recovery to baseline level against time since first treat-
ment, and summarised by percentiles of the recovery time
distribution.
RESULTS
Patients
Thirty-seven patients (17 men and 20 women) were followed
altogether. All patients had primary or secondary progressive
MS, with a median age of 39 years (23e56) at the time of first
alemtuzumab treatment and median duration since disease
onset of 9 years (range 1e23). Median disability at treatment
was EDSS 6 (4e8). Twenty-eight of 37 patients received a single
cycle of alemtuzumab; 9/37 patients received an additional
cycle, a median of 3.5 years after the first exposure. Baseline
lymphocyte subset levels were not available in 3/37 patients;
follow-up lymphocyte counts were available for a median of
Table 1 Details of the 15 patients with secondary progressive
multiple sclerosis that consented to lumbar punctures before and
after alemtuzumab treatment
No of patients 15
No of females (%) 10 (67)
Age at time of treatment (years) (median (range)) 40 (23e49)
Disease duration (years) (median (range)) 4 (1e13)
EDSS pretreatment (median (range)) 6 (4e7)
Time of pretreatment LP (days) (median (range)) 1 (0e37)
Time of post-treatment LP (months) (median (range)) 11 (3e28)
EDSS, Expanded Disability Status Score; LP, lumbar puncture.
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12 years (0.5e16) and clinical information (including by tele-
phone contact) for a median of 14 years (2e18). No patients
were lost to follow-up. The total duration of follow-up was 384
person years for lymphocyte counts and 447 person years for
clinical data. Twelve of 37 patients developed secondary auto-
immune disease.
Lymphocyte reconstitution
Figure 1 illustrates the total, CD19, CD4 and CD8 lymphocyte
counts from our cohort for a maximum of 16 years after a single
cycle of alemtuzumab. Total, CD4 and CD8 lymphocyte counts
all increased at a high rate of reconstitution for the first 12e18
months before the rate decreased. The median baseline
lymphocyte counts (with IQR) and upper and lower normal
limits (ULN, LLN, all 310
9
cells/l) were: total lymphocyte count
1.8 (IQR 1.4e2.3) (LLN 1.0, ULN 3.5); CD4 0.8 (0.71e1.01) (0.4,
1.5); CD8 0.42 (0.35e0.45) (0.2, 0.9); and CD19 0.19 (0.17e0.25)
(0.1, 0.5).
Total lymphocyte counts reconstituted to a ‘normal level’
(defined as $1.0310
9
cells/l) in 34/36 patients over a median of
12 years; the two patients not recovering to normal are excluded
from this analysis. The distribution of time to recovery was
strongly skewed to the right, with most patients’total
lymphocyte counts recovering within 2 years. Median recovery
time was 12.6 months (IQR 6.1e29.8 months). The log trans-
formed distribution of time taken to recovery was approxi-
mately symmetric (figure 2A) with the geometric mean closely
approximating the median. The geometric mean of recovery to
the normal level was 12.7 months (95% CI 8.8 to 18.2 months).
The total lymphocyte count recovery time to normal showed
little association with baseline age (r¼0.11) and a moderate
(negative) association with baseline total lymphocyte count
(r¼0.29). Total lymphocyte recovery tended to be 1.8 times
slower (95% CI 0.92 to 3.6, p¼0.08) for those patients who did
not develop autoimmunity (15.4 months) compared with those
who did (8.5 months, figure 2B).
Recovery of total lymphocyte counts to individual baseline
levels was achieved in only 14/36 patients (39%). To avoid
excluding these individuals, median recovery time was esti-
mated using survival analysis, yielding a figure of 151 months
(figure 2C; 95% CI 91 to 212). The 25th percentile of recovery
time was 38 months and more reliably estimated than the
median, as indicated by the confidence bands around the curve
at this point.
Thirty-four of 36 patients recovered B cell lymphocyte
counts to a normal level ($0.1310
9
/l), mostly within 2 years
(figure 3A). Median recovery time was 8.4 months. After log
transformation, the distribution showed greater symmetry than
on the original scale, but with a visual indication of bimodality
(figure 3B). The geometric mean was 7.1 months (95% CI 5.3 to
9.5). There was no association between autoimmune status and
CD19 recovery to ‘normal’levels.
In 31/36 patients (86%), CD8 lymphocyte counts recovered to
a normal level ($0.2310
9
/l); 27 patients in the first 4 years and
four in the next 8 years of follow-up (figure 4A). Median
recovery time was 20 months (95% CI 5 to 36). The 25th
percentile of recovery time was 6 months. No relationship was
found between mean CD8 recovery time to normal and auto-
immune status. In only 10/33 patients did CD8 lymphocyte
counts recover to baseline levels (figure 4B); median recovery
time was 155 months while the 25th percentile of recovery time
was 66 months.
Reconstitution of CD4 lymphocytes was slower; only 28/36
patients recovered to a normal CD4 level ($0.4310
9
/l) over
Figure 1 Raw data plots of total
lymphocyte counts (A), and CD19 (B),
CD4 (C) and CD8 subgroups (D) (all
310
9
cells/l) for years after
alemtuzumab. Broken lines indicate
upper and lower limits of normal range.
The solid line indicates the median (and
the grey shaded area the upper and
lower quartiles) of the baseline values.
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a median of 12 years (figure 4C). In the cumulative incidence
plot, the 25th percentile of recovery was more reliably estimated
than the median, being 27 months and 35 months, respectively.
Geometric mean recovery time to normal varied little by auto-
immunity and the differences were not significant. CD4 counts
recovered to baseline in only 7/33 patients (three patients having
missing baseline measurements). The median cannot be esti-
mated but the 25th percentile of recovery time was 112 months
(figure 4D).
Disability
Disability in all but one of the 37 patients continued to worsen
progressively despite alemtuzumab treatment, as previously
reported.
8 9
At the last recorded follow-up, a median of 14 years
post-treatment, the median disability estimated in 35/37
patients was EDSS 7.5 (range 4.5e9). Relapses were uncommon
but were not systematically captured.
Morbidity and mortality
Information on infections was not systematically collected from
the patients and many minor infections, common in the normal
population, will neither have been reported by patients nor have
generated a hospital record. From the information available there
were 11 major infections among the 37 patients, with two
occurring in the same patient. Most of these were pneumonia at
advanced stages of disability, with all five cases contributing to
death (one of which was noted to be secondary to aspiration).
Three cases of urinary sepsis were classified as severe because
they were notified as the cause of death. Deaths rates in the two
original cohorts of patients were 29% for the first cohort and
33% for the second cohort. Three further episodes of infection
were caused by necrotising gingivitis (previously reported),
9
a cervical epidural abscess and septicaemia secondary to a breast
abscess. Five patients reported segmental varicella zoster
virus reactivations, the majority occurring within 2e3 years of
treatment, with one reactivation 8 years after treatment. Again,
major infection rates were similar in the first and second cohorts
(29% and 30%, respectively). For patients undergoing surgical
procedures, including two cholecystectomies, a hernia repair and
a hemiarthroplasty, there was no excess post-surgical morbidity.
Fourteen patients developed Graves’s disease after treatment
with alemtuzumab (37.8%). Autoimmune disease in these two
cohorts appeared to be associated with female sex; 12 out of 21
women (57%) versus two out of 15 men (13%). However, this
has not been a consistent finding in the larger clinical trial
cohorts.
3 9
Two malignant tumours were recorded in the 37 patients at
follow-up: a case of prostatic adenocarcinoma in a patient who
was 55 years old at the time of treatment and one example of
skin basal cell carcinoma. One benign tumour was recorded: an
incidental meningioma found during MRI scanning. As of 9
August 2010, there had been 12 deaths among the 37 patients,
giving a mortality rate of 2.68 per 100 person years. Leaving
aside the two patients who committed suicide, the median
disability of the patients who died was EDSS 8 (range 6e9),
measured on average 3 years before death. Subsequent clinic
visits to measure EDSS became impossible as the patients
became increasingly dependent and institutionalised. Causes of
death in this group were infections associated with advanced
disability (table 2).
Figure 2 Recovery of total
lymphocyte counts (LC) following
alemtuzumab treatment. Thirty-four of
the 36 patients recovered their total LC
to a normal level, defined as
$1.0310
9
cells/l. (A) Distribution of
time taken to recovery to a normal level
after log transformation. (B) Box and
whisker plot of log total LC recovery
time to a normal level by autoimmune
status. 0¼no autoimmune disease,
1¼autoimmune disease (see methods
for definition, p¼0.08). One outlier
(greater than 1.53IQR) can be seen in
the autoimmune status¼1 group. (C)
Cumulative incidence curve plotting the
recovery distribution where an event is
the occurrence of total LC recovery to
the patient’s baseline level (solid line).
Vertical lines on the curve indicate
censored observationsdthat is,
patients were not followed-up further
due to death, retreatment or lack of
lymphocyte data. Broken lines are
95% CIs.
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OCB in cerebrospinal fluid
Paired CSF samples were taken before (range 0e37 days) and
after (range 3e28 months) the first (12 patients) or second
(three patients) cycle of alemtuzumab treatment. In all 15 cases,
analysis of the CSF demonstrated the persistence of OCB
following treatment with alemtuzumab.
DISCUSSION
We have reported the longest follow-up to date of patients with
MS after a single course of alemtuzumab treatment: 384 person
years of lymphocyte counts and 447 person years of clinical data
from 37 patients treated between 1991 and 1997. We have
shown that lymphocyte counts recovered to the lower limit of
the normal range within 8 months (B cells) and 3 years (T cell
subsets), but rarely returned to baseline values. No long
term safety signal emerges from this small cohort, other than
confirmation of the increased risk of autoimmunity.
As previously reported,
3 9
we observed faster reconstitution of
B cells after alemtuzumab than T cells; we have previously
shown that the B cell subtypes return at varying rates.
17
There
was a suggestion that those patients with a high baseline total
lymphocyte count recover to a normal, albeit lower, lymphocyte
count more rapidly than others. Interestingly, T cell numbers
returned to the normal range in nearly all patients (78% of
patients for CD4, 86% for CD8), but rarely to baseline levels
(21% of patients for CD4 and 30% for CD8). We speculate that
in adults with little thymic function, reconstitution of the T cell
pool after alemtuzumab may be ‘reset’to a lower threshold.
Furthermore, there may be sustained alterations within the
lymphocyte subsetsdsuch as those shown at 12 months.
18
This
suggests that simple lymphocyte counts may not be a reliable
assessment of immunocompetence.
Our previous study of lymphocyte reconstitution in this
cohort, assuming linear kinetics, suggested more rapid recon-
stitution of Tcells.
9
However, it is now clear that reconstitution
is initially linear and rapid, followed either by slowing of the rate
of increase and/or a subsequent fall in lymphocyte count. A
similar pattern of immune reconstitution is seen after alemtu-
zumab treatment of other autoimmune diseases or for organ
transplantation,
13 19e21
and after alemtuzumab in an hCD52
transgenic mouse, albeit on a much contracted timescale.
12
Long
term follow-up was possible in patients treated with alemtu-
zumab for refractory rheumatoid arthritis between 1991 and
1994.
22 23
This cohort was relatively older (median age 54 years,
range 25.5e70) and had received a median of four disease
modifying antirheumatic drugs (range 1e8) before treatment. At
a median of 11.8 years (range 10.5e13.3), post-treatment CD4,
CD8 and CD19 counts were 0.5, 0.26 and 0.11310
9
cells/l,
respectively.
23
Most had CD4 and CD8 T cell counts within the
normal range but, in contrast with this study, B cell counts were
subnormal in 50%. No excess mortality or infections were seen
in patients treated with alemtuzumab compared with a hospital
based rheumatoid arthritis cohort. Likewise, this lymphocyte
reconstitution profile after alemtuzumab was similar to that
seen following lymphopenia in other contexts, suggesting that it
is driven by common homeostatic mechanisms, for instance
after haematopoietic stem cell transplantation.
6132425
The lag
in CD4 cell recovery correlates with age of the recipient and
probably reflects impaired thymic function. Indeed, thymus
enlargement is evident radiographically in younger patients
following hematopoietic stem cell transplantation (HSCT)
26
and is seen in individuals treated with HSCT for both non-
Hodgkin’s lymphoma and MS.
27
Interestingly, CD4 reconstitu-
tion after HSCT for rheumatoid arthritis is considerably delayed,
an observation attributed to poor memory T cell expansion
associated with low levels of circulating interleukin (IL)-7.
28
However, in people with MS, serum IL-7 levels rise significantly
after alemtuzumab.
18
As expected from previous reports,
3 13
one-third of MS
patients develop autoimmunity after alemtuzumab, particularly
those prone to excessive IL-21 secretion.
16
Here we demon-
strated a non-significant trend that those patients who devel-
oped autoimmunity reconstituted their total lymphocytes
quicker (31.8) than those without autoimmunity. There are too
few data on lymphocyte subsets to judge whether their recon-
stitution differentiates between those with and without
autoimmunity.
We have also shown that alemtuzumab does not alter the
persistence of OCB in the CSF of patients with progressive MS
following treatment with alemtuzumab. Treatment with other
effective immunotherapies, such as rituximab
29
and autologous
HSCT, also do not eradicate intrathecal antibody
production.
30e36
These therapies, which so radically alter the
peripheral immune compartment, are clearly unable either to
Figure 3 Recovery of CD19 B cell counts following alemtuzumab
treatment. Thirty-four of the 36 patients recovered their B cells to
a normal level, defined as $0.1310
9
cells/l. (A) Distribution of time
taken for B cell recovery to a normal level. (B) Log transformation of time
taken for B cell recovery to a normal level.
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access or influence the plasma cells producing antibodies
detected in CSF.
No particular safety signal emerged from this study. No
patient was lost to follow-up and our data on death and major
safety events are complete. Segmental varicella zoster virus
reactivation, a feature of alemtuzumab treatment in the
CAMMS223 trial,
3
was seen in 5/37 patients. However, minor
adverse events were not systematically collected and the cohort
described here is small. The phase 3 trials of alemtuzumab will
add further information on long term safety after alemtuzumab
in the context of MS.
The fact that 12/37 of this progressive MS cohort died is
consistent with our experience of managing people with
untreated MS at this level of disability. Two of these 12
committed suicide, which is more common in MS.
37
The mean
disability of the remaining 10 patients was EDSS 8.1 on average
3 years before their death. The cause of death in these patients,
overwhelmingly due to sepsis from a urinary or chest source, is
typical of that in untreated patients with advanced disability
from MS.
38
Mortality increases with disability in MS: in
a Canadian cohort, people with an EDSS of $7.5 had an
increased death rate of four times that of controls
39
whereas it
Figure 4 Recovery of CD8 and CD4 T
cell counts following alemtuzumab
treatment. (A) Cumulative incidence
curve plotting the recovery distribution
where an event is the occurrence of
CD8 lymphocyte recovery to a normal
level, defined as $0.2310
9
cells/l
(solid line). Vertical lines on the curve
indicate censored observationsdthat
is, patients were not followed-up
further due to death, retreatment or lack
of lymphocyte data. Broken lines are
95% CIs. (B) Similar cumulative
incidence curve where an event is
defined as CD8 lymphocyte recovery to
the patient’s baseline level. (C)
Cumulative incidence curve where an
event is the recovery of CD4 T cells to
a normal level, defined as
$0.4310
9
cells/l. (D) Similar curve for
recovery of CD4 T cells to patient’s
baseline level.
Table 2 Details of the 12 patients that died from the cohort of 37 treated with alemtuzumab for progressive multiple sclerosis
Patient No
Age at first
alemtuzumab
treatment (years)
Time from first
dose to death (years) Last EDSS recorded
Time from last EDSS
to death (years) Cause of death
2 33 9 8 5.5 Pneumonia/MS
3 33 6 7.5 0.5 Urinary sepsis
4 48 10 7 4.0 Urinary sepsis
9 30 11 7.5 4.5 Unknown
17 31 10 8 0.5 Pneumonia
22 55 11 7.5 1.5 Prostate carcinoma
24 36 11 9 4.0 Pneumonia
25 34 13 9 7.0 Pneumonia
29 40 13 9 1.5 Pneumonia
35 23 6 8 1.0 Suicide
36 40 12 8.5 1.5 Urinary sepsis
37 42 3 6 1.0 Suicide
EDSS, Expanded Disability Status Score; MS, multiple sclerosis.
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Multiple sclerosis
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was increased eightfold in a French cohort with similar levels of
disability.
40
There is no indication that alemtuzumab treatment
or its complications were directly implicated in the deaths of
any patient in our study.
We conclude, from this small cohort, that one cycle of alem-
tuzumab has long lasting effects on the immune system,
possibly by resetting the target for reconstitution of T
lymphocytes to below baseline values: CD4 and CD8 T counts
enter the normal range by 3 years. Throughout, our patients
appeared immunocompetent, and the main complication of
alemtuzumab treatment remained autoimmunity. A caveat is
that current trial protocols for the treatment of rela-
psingeremitting MS require two cycles of alemtuzumab,
12 months apart, with possible re-treatment with evidence of
the return of disease activity. The long term effects of such
multiple alemtuzumab treatments have yet to be studied.
Acknowledgements The authors are grateful to Geoff Hale, Jenny Phillips and
members of the Therapeutic Antibody Centre, Oxford, for producing the
alemtuzumab (then called Campath-1H) used in this study. The authors are also
grateful to Dr Graham Wood and the Immunology Department of Addenbrookes
Hospital for lymphocyte phenotyping, some of which was supported by a grant from
NHS R&D, held by Professor Geoff Hale of the University of Oxford.
Funding During the course of this work, AJC was supported by an MRC Clinical
Training Fellowship, Wellcome Intermediate Fellowship and now by the Biomedical
Research Centre, Cambridge, NIHR. JLJ is also supported by the Biomedical Research
Centre, Cambridge, NIHR. The original studies were supported by a grant from
MuSTER.
Competing interests AJC, DASC and JLJ have received personal travel costs,
occasional honoraria and departmental support from Genzyme Corporation. GG has
received honoraria and consulting fees from Genzyme Corporation and Sanofi-Aventis.
Ethics approval Ethics approval was provided by the local research ethics
committees.
Contributors GAHC designed and performed the research, collected and interpreted
the data, and wrote the manuscript; TB performed the research, and collected and
interpreted the data; OT, JLJ, KM, JS, AG and GG conducted and performed research;
DASC designed the research and participated in the writing of the manuscript; MTF
performed the statistical analysis; and AJC designed and performed the research,
interpreted the data and participated in the writing of the manuscript.
Provenance and peer review Not commissioned; externally peer reviewed.
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304 J Neurol Neurosurg Psychiatry 2012;83:298e304. doi:10.1136/jnnp-2011-300826
Multiple sclerosis
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doi: 10.1136/jnnp-2011-300826
online November 5, 2011 2012 83: 298-304 originally publishedJ Neurol Neurosurg Psychiatry
Grant A Hill-Cawthorne, Tom Button, Orla Tuohy, et al.
sclerosisalemtuzumab treatment of multiple
Long term lymphocyte reconstitution after
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