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Tocilizumab in systemic lupus erythematosusData on safety preliminary efficacy and impact on circulating plasma cells from an open-label phase I dosage-escalation study.

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ARTHRITIS & RHEUMATISM
Vol. 62, No. 2, February 2010, pp 542–552
DOI 10.1002/art.27221
© 2010, American College of Rheumatology
Tocilizumab in Systemic Lupus Erythematosus
Data on Safety, Preliminary Efficacy, and Impact on Circulating Plasma Cells
From an Open-Label Phase I Dosage-Escalation Study
Gabor G. Illei,1 Yuko Shirota,1 Cheryl H. Yarboro,2 Jimmy Daruwalla,2 Edward Tackey,2
Kazuki Takada,2 Thomas Fleisher,3 James E. Balow,4 and Peter E. Lipsky2
curred in 11 patients; none was associated with neutropenia. Disease activity showed significant improvement,
with a decrease of >4 points in the modified Safety of
Estrogens in Lupus Erythematosus National Assessment version of the Systemic Lupus Erythematosus
Disease Activity Index score in 8 of the 15 evaluable
patients. Arthritis improved in all 7 patients who had
arthritis at baseline and resolved in 4 of them. Levels of
anti–double-stranded DNA antibodies decreased by a
median of 47% in patients in the 4 mg/kg and 8 mg/kg
dosage groups, with a 7.8% decrease in their IgG levels.
These changes, together with a significant decrease in
the frequency of circulating plasma cells, suggest a
specific effect of tocilizumab on autoantibody-producing
cells.
Conclusion. Although neutropenia may limit the
maximum dosage of tocilizumab in patients with SLE,
the observed clinical and serologic responses are promising and warrant further studies to establish the optimal dosing regimen and efficacy.
Objective. To assess the safety of interleukin-6
receptor inhibition and to collect preliminary data on
the clinical and immunologic efficacy of tocilizumab in
patients with systemic lupus erythematosus (SLE).
Methods. In an open-label phase I dosageescalation study, 16 patients with mild-to-moderate
disease activity were assigned to receive 1 of 3 doses of
tocilizumab given intravenously every other week for 12
weeks (total of 7 infusions): 2 mg/kg in 4 patients, 4
mg/kg in 6 patients, or 8 mg/kg in 6 patients. Patients
were then monitored for an additional 8 weeks.
Results. The infusions were well tolerated. Tocilizumab treatment led to dosage-related decreases in the
absolute neutrophil count, with a median decrease of
38% in the 4 mg/kg dosage group and 56% in the 8 mg/kg
dosage group. Neutrophil counts returned to normal
after cessation of treatment. One patient was withdrawn
from the study because of neutropenia. Infections ocClinicalTrials.gov identifier: NCT00046774.
Supported by the Intramural Research Program of the National Institute of Arthritis and Musculoskeletal and Skin Diseases,
NIH. This study was performed under a Collaborative Research and
Development Agreement with Chugai Pharmaceutical Company, Ltd.
1
Gabor G. Illei, MD, PhD, MHS, Yuko Shirota, MD, PhD:
National Institute of Arthritis and Musculoskeletal and Skin Diseases, and National Institute of Dental and Craniofacial Research,
NIH; 2Cheryl H. Yarboro, RN, BSPA, CCRC, Jimmy Daruwalla, BSc,
Edward Tackey, MD, Kazuki Takada, MD, Peter E. Lipsky, MD:
National Institute of Arthritis and Musculoskeletal and Skin Diseases,
NIH; 3Thomas Fleisher, MD: Department of Laboratory Medicine,
Clinical Center, NIH; 4James E. Balow, MD: National Institute of
Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland.
Address correspondence and reprint requests to Gabor G.
Illei, MD, PhD, MHS, Head, Sjögren’s Syndrome Clinic, National
Institute of Dental and Craniofacial Research, National Institutes of
Health, 10 Center Drive, Room 1N114, Bethesda, MD 20892. E-mail:
illeig@mail.nih.gov.
Submitted for publication October 20, 2008; accepted in
revised form October 16, 2009.
Autoantibody production, complement activation, immune complex deposition, and leukocyte infiltration of target organs are key immunopathogenic
events in systemic lupus erythematosus (SLE). Multiple
cytokines have been implicated in the regulation of
disease activity or organ involvement in SLE. Among
these, interleukin-6 (IL-6), which exerts pleiotropic effects on numerous cell types (1), is thought to play an
important role. In murine models of lupus, an ageassociated increase in serum levels of IL-6 and abnormal
expression of the IL-6 receptor have been described
(2–4). The addition of exogenous IL-6 was shown to
increase autoantibody production and accelerate the
progression of glomerulonephritis (5,6), whereas block542
IL-6 RECEPTOR BLOCKADE IN SLE
ade of IL-6 or its receptor was shown to prevent
increased anti–double-stranded DNA (anti-dsDNA) antibody levels and progression of proteinuria and to
improve mortality rates (7–9).
Lupus patients have elevated serum levels of IL-6
(10–13), which were found to be correlated with disease
activity or with anti-dsDNA levels in some, but not all,
studies. Moreover, neutralization of IL-6 led to a significant decrease in the spontaneous production of immunoglobulin (12) and anti-dsDNA in vitro (14). Several
studies have demonstrated increased urinary excretion
of IL-6 in patients with active proliferative lupus nephritis (13,15,16). IL-6 excretion was found to be decreased
following cyclophosphamide treatment, suggesting that
IL-6 may play an important role in lupus nephritis.
Based on these data, we hypothesized that blocking the
effect of IL-6 may be beneficial in SLE.
Tocilizumab, a humanized monoclonal antibody
against the ␣-chain of the IL-6 receptor, prevents the
binding of IL-6 to membrane-bound and soluble IL-6
receptor (17). The safety and efficacy of tocilizumab
have been evaluated in clinical trials in patients with
rheumatoid arthritis (RA), juvenile idiopathic arthritis,
and Castleman’s disease (18). Herein, we report the
findings of a pilot clinical study of tocilizumab treatment
in patients with SLE.
PATIENTS AND METHODS
Study design. This was an open-label phase I dosageescalation pilot study to evaluate the safety and tolerability of
tocilizumab in patients with SLE and to obtain preliminary
evidence of its potential efficacy in this disease. The study was
approved by the Institutional Review Board of the National
Institute of Arthritis and Musculoskeletal and Skin Diseases,
National Institutes of Health (NIH). All patients signed informed consent forms.
Patient selection. Between 2003 and 2005, 16 adult
patients (age ⬎18 years) who fulfilled the American College of
Rheumatology classification criteria for SLE (19,20) and attended the NIH Clinical Center were enrolled in the study. All
patients had moderately active lupus, as defined by 1 of the
following 2 sets of criteria. Criteria set 1 consisted of the
presence of chronic glomerulonephritis, with an inadequate
response to at least 6 months of adequate immunosuppressive
therapy (with either methylprednisolone pulse doses, cyclophosphamide, azathioprine, cyclosporine, mycophenolate
mofetil, high-dose daily corticosteroids, methotrexate, or intravenous immunoglobulin [IVIG]), plus the following 4 features:
less than a 30% increase in serum creatinine levels as compared with the lowest level achieved during treatment; proteinuria at levels ⱕ1.5 times the value at baseline (before treatment); ⱕ2⫹ cellular casts in the urinary sediment; and
extrarenal disease activity not exceeding a score of 10 on the
543
nonrenal components of the Safety of Estrogens in Lupus
Erythematosus National Assessment (SELENA) version of
the Systemic Lupus Erythematosus Disease Activity Index
(SLEDAI) (21).
Criteria set 2 consisted of moderately active extrarenal
lupus, which was defined as an extrarenal SELENA–SLEDAI
score in the range of 3–10. The SELENA–SLEDAI score must
have been stable for at least 2 weeks prior to screening.
Because 2 of the main effects of IL-6 are on inflammatory responses and antibody production, we required the
presence of at least 1 serologic marker of autoantibody production or systemic inflammation. Thus, 1 or more of the
following 4 features had to be present in eligible patients: a
serum anti-dsDNA antibody level ⱖ30 IU, an IgG anticardiolipin antibody level ⱖ20 IgG phospholipid units/ml, a
C-reactive protein level (CRP) ⬎0.8 mg/dl, or an erythrocyte
sedimentation rate (ESR) ⬎25 mm/hour in men and ⬎42
mm/hour in women. Patients who were taking prednisone (or
equivalent) were required to have been taking a stable dosage
of ⱕ0.3 mg/kg/day for at least 2 weeks before the first dose of
study medication was administered. Patients were required to
use an effective form of contraception throughout the study.
The main exclusion criteria included pregnancy;
any therapy with human or murine antibodies or any
experimental therapy within 3 months; therapy with cyclophosphamide; pulse methylprednisolone or IVIG within 4
weeks; or azathioprine, mycophenolate mofetil, cyclosporine, or methotrexate within 2 weeks of the first dose of
study medication. Patients with any of the following abnormal findings on laboratory tests were also excluded: serum
creatinine level ⬎3.0 mg/dl, white blood cell count ⬍3,500/
␮l, absolute neutrophil count ⬍3,000/␮l, absolute lymphocyte count ⱕ500/␮l, hemoglobin value ⬍8.0 gm/dl, platelet
count ⬍50,000/␮l, alanine aminotransferase and/or aspartate aminotransferase (AST) level ⬎1.5 times the upper
limit of normal, alkaline phosphatase level ⬎1.5 times the
upper limit of normal, or ⬎1,000 Epstein-Barr virus genome
equivalents/106 peripheral blood mononuclear cells.
Study medication protocol. The tocilizumab was provided by Chugai Pharmaceutical (Tokyo, Japan). Study subjects were assigned to receive 1 of the following 3 doses of
tocilizumab: group 1 (n ⫽ 4) received 2 mg/kg, group 2 (n ⫽ 6)
received 4 mg/kg, and group 3 (n ⫽ 6) received 8 mg/kg.
Tocilizumab was administered intravenously every 2 weeks for
12 weeks, for a total of 7 infusions.
Concomitant immunosuppressive therapy. Patients
who were taking prednisone (or equivalent) at study entry
were required to be receiving a dosage of ⱕ0.3 mg/kg/day. The
prednisone dosage was kept stable during the first 7 weeks of
treatment. After that time, a gradual tapering of the dosage to
0.15 mg/kg/day was allowed. Temporary increases in the
prednisone dosage were allowed based on disease activity.
Patients had to be withdrawn from the study if a prednisone
dosage ⱖ0.5 mg/kg/day was required or if there was no
response to a 2-week course of prednisone (or equivalent) at a
dosage of ⱕ0.5 mg/kg/day. The following medications were
allowed, provided that they were administered at stable dosages for at least 2 weeks before, as well as during, the study:
hydroxychloroquine, nonsteroidal antiinflammatory drugs,
angiotensin-converting enzyme inhibitors, and angiotensin receptor antagonists.
544
Safety and toxicity analyses. Patients were monitored
during the infusions of study medication and every 2–4 weeks
for the 5-month study period. Safety assessments included
unexpected toxicities, adverse events encountered during or
after the drug infusion, changes in vital signs, and changes in
clinical laboratory data. Adverse events were graded according
to the National Cancer Institute Common Toxicity Criteria
(CTC) guidelines. Upon occurrence of a grade 3 or 4 adverse
event, which was at least possibly related to the study drug,
tocilizumab was discontinued unless the event resolved spontaneously within 9 days. Patients who were withdrawn from
treatment received 8 weeks of followup after withdrawal.
Efficacy analysis. Clinical and laboratory data were
collected for preliminary evaluation of the potential activity of
tocilizumab on the SLE as well as the measures of inflammation. Parameters used for efficacy measures were assessed at
the initial screening, prior to selected study drug infusions
(weeks 0, 2, 4, 6, and 12), and during followup visits (weeks 14,
16, and 20).
Lupus activity indices and serologic markers of disease
activity and inflammation were used to assess efficacy. Lupus
activity indices consisted of the Systemic Lupus Activity Measure (SLAM) (22) and the modified SELENA–SLEDAI
(mSELENA–SLEDAI). This latter index was modified to omit
1 of the standard parameters (“low complement”) because
tocilizumab has been shown to lower complement levels in RA
patients independently of disease activity (Tocilizumab Investigator’s Brochure). The following serologic markers of SLE
were determined: anti-dsDNA antibodies, anticardiolipin antibodies, antinuclear antibodies, anti–extractable nuclear antigen. In addition, quantitative assessments of immunoglobulins
(IgG, IgA, and IgM) and markers of inflammation (CRP, ESR,
fibrinogen, and ferritin) were performed.
Measurement of complement activation products
(CAP). Complement activation products iC3b, C4d, and C5b–9
were measured in plasma by enzyme-linked immunosorbent
assay (Quidel, San Diego, CA) according to the manufacturer’s
instructions.
Flow cytometry. Flow cytometric analysis was performed using a FACSCalibur flow cytometer with CellQuest
Pro software (both from Becton Dickinson, Mountain View,
CA).
Statistical analysis. The safety analysis included every
patient who received ⱖ1 infusion of the study drug. The
efficacy analysis included patients who received at least 3
infusions of tocilizumab. Continuous variables were summarized, with means, standard deviations, medians, and ranges
reported. Categorical variables were summarized by frequencies and counts of patients in the corresponding categories. All
statistical tests were performed at the 0.05 significance level,
and all confidence intervals were 95% 2-sided intervals.
No formal sample size calculation was performed,
since this study was designed predominantly to explore the
tolerability and safety of these regimens. The choice of 16
patients was based on the experience with similar studies in the
past. The study was not powered to detect differences between
groups or to confirm efficacy. Therefore, there is a risk of
false-positive results because of the large number of end points
being considered. As a consequence, results of efficacy analyses comparing the dosage groups are exploratory in nature.
ILLEI ET AL
RESULTS
Characteristics of the SLE patients at baseline.
Sixteen SLE patients (13 women and 3 men) from
various ethnic backgrounds and with moderate disease
activity were enrolled in the study. The baseline demographic and clinical characteristics are shown in Table 1.
The mean mSELENA–SLEDAI score was 11.5, 10, and
8 in the 2 mg/kg, 4 mg/kg, and 8 mg/kg dosage groups,
respectively. All but 1 of the patients were taking
prednisone. All 12 of the patients who were taking
hydroxychloroquine had been receiving stable dosages
for at least 3 months prior to the first dose of study
medication. Fifteen patients received 7 infusions of
tocilizumab (4 at 2 mg/kg, 6 at 4 mg/kg, and 5 at 8
mg/kg). One patient in the 8 mg/kg dose group was
withdrawn after the first infusion because of grade 3
neutropenia.
Findings of the safety analyses. The infusions
were well tolerated, without any clinically significant
infusion reactions. All patients experienced 1 or more
tocilizumab treatment-related adverse events; however,
most of these were mild and resolved spontaneously.
Serious adverse events. There were 2 serious adverse events, both of which occurred in the same patient;
this patient was in the group receiving 8 mg/kg of
tocilizumab. The first serious adverse event was a hospitalization for acute gastroenteritis 10 days after the
second infusion. A detailed diagnostic evaluation failed
to identify any specific cause. The patient recovered
spontaneously and completed the treatment course. At 8
weeks after the last tocilizumab dose, this same patient
developed acute pyelonephritis, which responded well to
treatment with intravenous antibiotics. In addition to
these 2 serious adverse events, 2 patients in the group
receiving 8 mg/kg experienced severe neutropenia, with
an absolute neutrophil count of 500–1,000/␮l (CTC
grade 3).
Infections. Eleven patients (4 receiving 2 mg/kg of
tocilizumab, 4 receiving 4 mg/kg, and 3 receiving 8
mg/kg) experienced a total of 16 infections between the
start of study treatment and the end of the followup
period (Table 2). Two patients experienced repeated
infections. The majority of these were upper respiratory
tract (n ⫽ 5) or urinary tract (n ⫽ 3) infections. Ten of
the 16 episodes of infection were treated with systemic
antibiotics or antivirals. No infection led to withdrawal
from the study, but the next tocilizumab infusion was
delayed by 2 weeks when 1 patient in the 2 mg/kg dosage
group experienced herpes zoster keratitis. This responded to treatment with antiviral agents and did not
IL-6 RECEPTOR BLOCKADE IN SLE
545
Table 1. Baseline characteristics of the SLE patients in the safety and efficacy analyses, by tocilizumab dosage group*
Tocilizumab dose
All patients
Safety analysis
No. of patients
Age, median (range) years
No. (%) female
Ethnicity, no. (%)
Caucasian
African American
Other†
Duration of SLE, median (range) years
Efficacy analysis
No. of patients‡
No. (%) with renal involvement
mSELENA–SLEDAI, median (range) score§
SLAM, median (range) score
Anti-dsDNA
No. (%) positive
Median (range) level, IU/ml‡
Prednisone dosage, median (range) mg/day
2 mg/kg
16
36.5 (23–54)
13 (81.3)
4 mg/kg
4
34.5 (23–37)
4 (100)
9 (56.3)
5 (31.3)
2 (12.4)
14.5 (1.3–23.6)
1 (25)
1 (25)
2 (50)
11 (1.3–22.8)
15
5 (33.3)
8 (4–15)
8 (2–12)
4
2 (50)
11.5 (4–15)
8 (4–12)
13 (86.7)
192 (0–1,849)
7.5 (0–20)
8 mg/kg
6
47.5 (26–54)
4 (66.7)
6
38.0 (28–47)
5 (83.3)
4 (66.7)
2 (33.3)
0 (0)
16.7 (6.5–23.6)
4 (66.7)
2 (33.3)
0 (0)
15.6 (4.9–19.9)
6
1 (16.7)
10 (4–14)
8 (2–9)
4 (100)
124 (37–457)
7.5 (1.25–10)
4 (67)
121.5 (0–872)
6.25 (2.5–15)
5
2 (40)
8 (6–10)
7 (2–10)
5 (100)
201 (51–1,849)
10 (0–20)
* Tocilizumab was administered every other week for 12 weeks (total of 7 infusions). SLE ⫽ systemic lupus erythematosus; SLAM ⫽ Systemic Lupus
Activity Measure; anti-dsDNA ⫽ anti–double-stranded DNA.
† One of these 2 patients was Asian, and the other was Hispanic.
‡ One African American man assigned to receive 8 mg/kg of tocilizumab was withdrawn after the first infusion because of grade 3 neutropenia.
§ Hypocomplementemia was excluded from scoring on the modified Safety of Estrogens in Lupus Erythematosus National Assessment version of
the Systemic Lupus Erythematosus Disease Activity Index (mSELENA–SLEDAI). See Patients and Methods for details.
recur after tocilizumab was resumed. All other patients
continued their tocilizumab therapy uninterrupted while
being treated for their infection.
Changes in blood chemistry parameters. A slight
increase in the mean AST level, but within the range of
normal, was seen during the study period. The mean
levels of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides increased slightly during the early treatment
period, but there were no clinically or statistically signif-
Table 2. Treatment-emergent infections observed during the study period*
Tocilizumab
dose
2 mg/kg
Patient
Patient
Patient
Patient
Patient
Patient
Patient
4 mg/kg
Patient
Patient
Patient
Patient
8 mg/kg
Patient
Patient
Patient
Patient
Patient
Infection
Time point
(week)
SAE
001
002
002
002
002
003
004
Urinary tract infection
Folliculitis
Upper respiratory tract infection
Otitis media
Urinary tract infection
Sinusitis
Upper respiratory tract infection
14
2
5
5
20
16
13
No
No
No
No
No
No
No
Oral antibiotics
Topical antibiotics
Oral antibiotics
Oral antibiotics
Oral antibiotics
Oral antibiotics
Oral antibiotics
005
007
Upper respiratory tract infection
Herpes zoster keratitis
15
5
No
No
009
010
Upper respiratory tract infection
Oral candidiasis
8
2
No
No
Oral antibiotics
Tocilizumab infusion delayed by
2 weeks; antiviral
Symptomatic
Topical antifungal
013
013
013
014
020
Urinary tract infection
Labial herpes simplex
Acute pyelonephritis
Upper respiratory tract infection
Fungal vaginosis
12
13
20
1
3
No
No
Yes
No
No
Oral antibiotics
None
Intravenous antibiotics
Symptomatic
Oral antifungal
Treatment
* Tocilizumab was administered every other week for 12 weeks (total of 7 infusions). SAE ⫽ serious adverse event.
546
icant changes by the end of treatment (data not shown).
The albumin levels increased from a mean of 3.45 mg/dl
to 3.77 gm/dl (P ⫽ 0.001 by Student’s t-test).
Changes in hematologic parameters. The mean
platelet counts decreased slightly with treatment, but the
changes were not clinically significant. Conversely, the
hematocrit and hemoglobin values showed gradual and
sustained increases over the treatment period, with a
maximum mean increase in the hemoglobin value of 1.54
gm/dl at week 16 in the group receiving 8 mg/kg of
tocilizumab. (Data from the assessment of hematologic
parameters over the course of the study are available
upon request from the corresponding author.)
White blood cell counts decreased in all dosage
groups, largely because of the dose-related reduction in
absolute neutrophil counts. Most of the change in neutrophil counts occurred following the first dose, reaching
a maximum at the end of the treatment phase and
returning to baseline levels by week 20 of followup
(Figures 1a and b). The median decrease at 14 weeks (2
weeks after the last treatment) was 2% (range 0–15%) in
those receiving 2 mg/kg of tocilizumab, 38% (range
7–42%) in those receiving 4 mg/kg, and 56% (range
48–72%) in those receiving 8 mg/kg. Two patients in the
8 mg/kg dosage group had CTC grade 3 neutropenia
(absolute neutrophil count ⬍1,000/␮l). One of these
patients was withdrawn from the study after the first
dose of tocilizumab. In the other patient, the neutropenia occurred 2 weeks after the last infusion of tocilizumab. Neither of these patients had any infections or
other clinical consequences of the neutropenia, and their
neutrophil counts recovered spontaneously off study
drug treatment.
Findings of the efficacy analyses. Fifteen patients
were included in the preliminary efficacy analysis. All of
these patients had completed the 7 infusions of study
drug as well as the followup assessments.
Changes in markers of inflammation. The levels of
all acute-phase reactants decreased promptly and significantly upon tocilizumab treatment, confirming the biologic activity of tocilizumab. Most changes occurred
after the first dose and were maintained during the
treatment period, particularly the ESR and fibrinogen
levels (P ⬍ 0.001 at 6 and 14 weeks for both acute-phase
reactants). (Data from the assessment of the ESR and
fibrinogen levels over the course of the study are available upon request from the corresponding author.)
Serologic response. There were clear dose-related
decreases in the levels of complement C3 and C4. Since
a decrease in complement levels can be caused by either
decreased production or increased consumption, we
measured the levels of the complement activation prod-
ILLEI ET AL
Figure 1. Changes in absolute neutrophil counts and complement products in patients with systemic lupus erythematosus receiving treatment
with 2 mg/kg, 4 mg/kg, or 8 mg/kg of tocilizumab from baseline to week 14
of study. a and b, There was a dose-dependent decrease in the absolute
neutrophil count (ANC), including the number of neutrophils per microliter (a) and the proportional change from baseline (b), during treatment.
These values returned to baseline during the followup period after
treatment. c, Tocilizumab led to a similar decrease in the levels of complement C3 and of the complement activation products iC3b and
C5b–9 (terminal membrane attack complex), all of which returned to
baseline during the followup period after treatment. Values are the
mean ⫾ SEM. ⴱ ⫽ P ⬍ 0.005 for the whole cohort at the indicated time
points as compared with baseline, by repeated-measures analysis of
variance.
ucts iC3b, C4d, and C5b–9 in 10 patients in the 4 and 8
mg/kg dosage group. All of these complement activation
products showed decreased absolute levels or decreased
IL-6 RECEPTOR BLOCKADE IN SLE
547
Figure 2. Serologic changes in patients with systemic lupus erythematosus receiving treatment with 2
mg/kg, 4 mg/kg, or 8 mg/kg of tocilizumab from baseline to week 14 of study. a, Levels of anti–doublestranded DNA (anti-dsDNA) antibodies decreased during treatment in all tocilizumab dosage groups
(left), but mainly in the combined group of patients receiving the medium and high dosages (right). b, The
proportional change in anti-dsDNA levels was substantially higher than the small, not statistically
significant, decrease in IgG levels in all tocilizumab dosage groups (left), especially in the combined group
of patients receiving the medium and high dosages (right). Only patients who had anti-dsDNA antibodies
at baseline (n ⫽ 13 in the entire cohort; n ⫽ 9 in the medium/high dose only group) were included in these
analyses. Data are shown as box plots. Each box represents the 25th to 75th percentiles, the lines within
the boxes represent the median (50th percentile), and the lines outside the boxes represent the 10th and
90th percentiles. Solid circles indicate outliers. P values comparing the end of treatment data with the
baseline data were determined by Wilcoxon’s signed rank test.
levels relative to C3 (Figure 1c) or C4, with the levels of
the terminal membrane attack complex decreasing most
significantly.
There were no significant changes in IgA and
IgM levels, but by the end of the treatment period, IgG
levels had decreased by a median of 130 mg/dl (minimum –660, maximum ⫹230 mg/dl; P ⫽ 0.04 by Wilcoxon’s signed rank test) as compared with baseline.
Next, we evaluated the effect of tocilizumab on
anti-dsDNA levels. Thirteen patients had detectable
anti-dsDNA antibodies at baseline, ranging from 37
IU/ml to 1,849 IU/ml (normal ⬍25). The median decrease in anti-dsDNA antibody levels at week 14 was ⫺9
IU/ml (minimum ⫺417, maximum ⫹125; P ⫽ 0.03 by
Wilcoxon’s signed rank test) (Figure 2a). To adjust for
the wide range of baseline values, we also evaluated the
proportional change in IgG and anti-dsDNA levels in
these 13 patients and found that the relative change in
anti-dsDNA levels was twice as much (median ⫺17.6%)
as the relative change in IgG levels (median ⫺7.91%)
(Figure 2b).
In contrast to the findings in the 4 mg/kg and 8
mg/kg dosage groups, where we did not observe any
increase in anti-dsDNA antibodies, 2 of 4 patients in the
2 mg/kg dosage group had an increase level of antidsDNA antibodies at week 14. Therefore, we performed
a subgroup analysis of the 9 patients in the combined
medium- and high-dose groups (4 and 8 mg/kg) who had
anti-dsDNA antibodies at baseline (range 51–1,849 IU/
ml). In these patients anti-dsDNA antibody levels decreased by a median of ⫺113 IU/ml (minimum ⫺417,
maximum ⫹1; P ⫽ 0.01 by Wilcoxon’s signed rank test)
548
ILLEI ET AL
Figure 3. Changes in circulating plasma cells in patients with systemic lupus erythematosus (SLE) receiving treatment with 2 mg/kg, 4 mg/kg,
or 8 mg/kg of tocilizumab from baseline to week 14 of study. a, Percentages of plasma cells in healthy control subjects (n ⫽ 14) versus SLE
patients (n ⫽ 13) at baseline. Patients had a significantly higher proportion of plasma cells at baseline as compared with healthy controls
(determined by Student’s t-test). Each data point represents a single subject; the open circles joined with a line show the mean of each group.
b, Flow cytometry showing the response to tocilizumab at baseline and week 12 in a representative SLE patient. There was a change in
circulating CD38⫹⫹⫹IgD– plasma cells before and after therapy. Values shown in each compartment are percentages. Cell subsets in the
lower compartments are defined at the bottom. c, Frequency of plasma cells in the SLE patients at baseline, week 6, week 14 (end of
tocilizumab treatment), and week 20 (end of followup). The frequency of plasma cells decreased significantly with tocilizumab treatment.
Values are the mean ⫾ SEM. P value was calculated by repeated-measures analysis of variance, with the Bonferroni/Dunn correction for
multiple comparisons.
at week 14 (Figure 2a). Analysis of the proportional
changes in these patients showed a small, but statistically
significant, change in the IgG levels (median change
–7.8% [minimum –32.7%, maximum 0.0%]; P ⫽ 0.01) at
the end of treatment (week 14). However, this was much
smaller than the –46.8% change in anti-dsDNA levels
(minimum –62.7%, maximum 0.52%; P ⫽ 0.01) (Figure
2b). In fact, 5 of 9 patients had a ⬎45% decrease in the
anti-dsDNA antibody level.
The levels of other autoantibodies we measured,
such as antinuclear antibodies, anti-SSA, anti-SSB, and
anticardiolipin antibodies, did not change significantly.
Changes in peripheral plasma cell frequency. There
were no significant changes in the total number of
lymphocytes or in the overall T lymphocyte or B lymphocyte counts. The frequency of CD38highCD19lowIgD–
plasma cells was significantly expanded in SLE patients
at baseline as compared with healthy controls (mean
5.3% versus 1.2%) (Figure 3a). The response to tocilizumab by the end of treatment in a representative SLE
patient is shown in Figure 3b. For the entire cohort, a
significant reduction in the percentages of plasma cells
was seen as early as 6 weeks (mean 3.05%) (Figure 3c).
This was maintained throughout the treatment (mean
3.43% at 14 weeks) and followup (mean 3.46% at 20
weeks) periods.
Clinical response. Disease activity showed a modest but significant improvement by the end of the
treatment period (Figure 4). Mean SLAM scores decreased from 7.1 at baseline to 5.0 at week 14 (P ⫽
0.002), and mean mSELENA–SLEDAI scores decreased from 9.5 to 5.5 (P ⫽ 0.001). The decrease in the
SLAM score was mainly related to improvement in the
ESR, the degree of fatigue, and the hematocrit value,
whereas the decrease in the mSELENA–SLEDAI score
was mainly because of improvement in arthritis and rash.
A clinically significant improvement in the mSELENA–
SLEDAI score was predefined as a decrease of ⱖ4
points from baseline. This was achieved by 8 of 15
patients (3 each in the 2 mg/kg and 4 mg/kg groups and
2 in the 8 mg/kg group). Five of these 8 patients also
achieved the recently proposed (23) criteria of an improvement of ⱖ7 points. Using a similar approach for
the SLAM scores, 5 patients had an improvement of ⱖ4
points (1 in the 2 mg/kg group and 2 each in the 4 mg/kg
and 8 mg/kg groups), and none had an improvement of
ⱖ7 points. There was a significant decrease from baseline in both the physician’s and the patient’s global
assessment of disease activity (mean ⫾ SD change from
baseline –1.7 ⫾ 1.2 for the physician’s global assessment
and –1.7 ⫾ 1.7 for the patient’s global assessment; P ⬍
0.002 for both comparisons). Interestingly, both the
IL-6 RECEPTOR BLOCKADE IN SLE
Figure 4. Clinical efficacy of treatment with 2 mg/kg, 4 mg/kg, or 8
mg/kg of tocilizumab from baseline to week 14 in patients with
systemic lupus erythematosus (SLE). a, Swollen joint counts at baseline, week 6, week 14 (end of tocilizumab treatment), and week 20 (end
of followup) in 7 SLE patients who had arthritis at baseline. In all 7
patients, there was an improvement in arthritis, as determined by the
swollen joint count, with tocilizumab treatment, with complete resolution in 4 patients. Data are shown as box plots. Each box represents
the 25th to 75th percentiles, the lines within the boxes represent the
median (50th percentile), and the lines outside the boxes represent the
10th and 90th percentiles. Solid circles indicate outliers. P values
comparing the end of treatment data with the baseline data were
determined by Wilcoxon’s signed rank test. b, Scores on the modified
Safety of Estrogens in Lupus Erythematosus National Assessment
version of the Systemic Lupus Erythematosus Disease Activity Index
(mSELENA–SLEDAI) and the Systemic Lupus Activity Measure
(SLAM) at baseline, weeks 6, week 14 (end of tocilizumab treatment),
and week 20 (end of followup) in the 15 SLE patients evaluated for
efficacy. There was improvement in overall disease activity over the
course of treatment, with the mSLEDAI and SLAM scores showing a
significant decrease at the end of treatment. Values are the mean and
SD. P values were determined by repeated-measures analysis of
variance.
physician’s and the patient’s global assessments decreased significantly in the 2 mg/kg and 4 mg/kg groups,
but not in the 8 mg/kg group.
549
Seven patients (4 receiving 4 mg/kg of tocilizumab and 3 receiving 8 mg/kg) had arthritis at baseline.
The mean number of swollen joints improved from 7.7 at
baseline to 5.4 at 6 weeks and 1.1 at the end of the
treatment period, with complete resolution of arthritis in
4 patients. At the last followup, 5 of the 7 patients had a
reactivation of their arthritis (mean swollen joint count
5.4). Six patients had an inflammatory rash at the start of
tocilizumab treatment, which resolved in 3 of them
between weeks 2 and 6. Fatigue, as assessed by the
SLAM, was present in 7 patients at baseline and resolved in 6 of them. There were 3 patients without
fatigue at baseline who reported having fatigue on at
least 1 occasion during the treatment period; in none of
these patients was the fatigue sustained.
Five patients had renal disease at baseline. All
had moderate proteinuria, 4 had pyuria, and 3 had
hematuria. None had cellular casts. Other causes of
these abnormalities, such as infection, diabetes mellitus,
and uncontrolled hypertension, were excluded before
these abnormalities were attributed to the SLE. There
was no significant change in the mean level of proteinuria during the study. The number of patients with active
urinary sediment was too low to assess efficacy, but 2 of
2 patients with significant hematuria (urinary red blood
cell count ⬎10 per high-power field) at baseline (determined as the average of the screening and pretreatment
values) and 3 of 4 with significant pyuria (urinary white
blood cell count ⬎10 per high-power field) had ⬎50%
improvement at the end of treatment (average of week
12 and week 14 values).
Most patients (12 of 15) were taking ⱕ10 mg of
prednisone (or equivalent) daily which was kept stable
during the study. The prednisone dosage was successfully decreased by an average of 7.5 mg/day in the 3
patients who were taking either 15 mg/day (n ⫽ 1) or 20
mg/day (n ⫽ 2) at study entry.
There was no SLE flare during the treatment
period. One patient receiving 4 mg/kg of tocilizumab
experienced a flare 2 weeks after her last dose and
required an increase in her prednisone dosage from 7.5
mg/day to 15 mg/day. Two other patients in the group
receiving 2 mg/kg of tocilizumab required an increase in
the prednisone dosage at the last followup visit; one of
them also received methotrexate for the treatment of
arthritis and rash.
DISCUSSION
Our data provide the first evidence that blocking
IL-6 receptors with tocilizumab has an acceptable safety
550
profile and suggest a possible immunologic and clinical
benefit in SLE. Patients tolerated the infusions well,
with no infusion reactions. Infections were the most
common adverse events, with two-thirds of the patients
experiencing at least 1 infection during the 5-month
study period. Although the rate of infections was higher
than expected, consistent with other studies of tocilizumab (24–26), most of these infections were mild and
resolved with or without antibiotics during continued
tocilizumab therapy. Larger controlled studies will be
necessary to obtain a better estimate of the risk of
infection associated with tocilizumab as compared with
the risk with other drugs used to treat SLE. Liver
enzyme abnormalities and increases in serum lipid levels
have been described with tocilizumab therapy (25–27).
We did not observe any clinically important abnormal
findings on liver function tests because patients with
significant elevations in liver enzyme levels and those
taking potentially hepatotoxic medications were excluded from the study.
The main adverse event in this study was doserelated neutropenia. Absolute neutrophil counts decreased by a median of 38% and 56% in the 4 mg/kg and
8 mg/kg tocilizumab groups, respectively. Most of the
changes occurred after the first dose and remained
relatively stable during the treatment. Similar decreases
in neutrophil counts have been observed in other studies. In the OPTION (Tocilizumab Pivotal Trial in Methotrexate Inadequate Responders) study, one-third of the
patients with RA who were treated with 8 mg/kg of
tocilizumab every 4 weeks in combination with stable
dosages of methotrexate had an absolute neutrophil
count below the lower limit of normal at least once
during the study (24). This is comparable to what we
have observed in lupus patients who received 4 mg/kg of
tocilizumab every 2 weeks. It is very important to note
that neutropenia did not temporally correlate with the
occurrence of infections in either study. The cause of the
decline in the neutrophil count is not clear and requires
further investigation. It may be related to decreased
production or, more likely, to changes in neutrophil
trafficking, or both.
IL-6 plays a major role in regulating the acutephase responses of inflammation, and blocking IL-6 is
expected to reverse these effects. Accordingly, elevated
levels of markers of inflammation decreased promptly
following the first dose and remained stable during the
treatment phase. The antiinflammatory effect of tocilizumab was further supported by an improvement in
hemoglobin values and serum albumin levels. In this
ILLEI ET AL
study, we did not see a significant improvement in
proteinuria, and therefore, the improvement in albumin
levels is a reflection of a decrease in systemic inflammation. The most common form of anemia in SLE is
anemia of chronic inflammatory disease. Since red blood
cells play a major role in the clearance of immune
complexes, correcting the anemia may increase the
clearance of circulating immune complexes and may
thus contribute to a decrease in disease activity (28) in
addition to improving oxygen-carrying capacity and tissue oxygenation.
Tocilizumab treatment was associated with hypocomplementemia in previous studies, but it was not
known if this was explained by a decreased production or
an increased consumption of complement components.
Our data showing that complement activation products
decreased to a similar or higher degree as the C3 and C4
levels provide the first evidence that the tocilizumabassociated hypocomplementemia represents decreased
production rather than increased activation. Since hypocomplementemia can also herald active lupus, complement activation products, rather than common complement components, should be used as markers of lupus
activity in future studies of tocilizumab.
Fifteen patients were available for evaluation of
efficacy. Although the number of patients was too small
for a formal comparison among the 3 dosage groups, we
did not detect any obvious differences in clinical outcomes among them. The findings in the 4 patients
receiving 2 mg/kg were similar to those in the 11 patients
receiving 4 mg/kg and 8 mg/kg, with more individual
variations and a delayed onset of response. Overall
disease activity, as measured by 2 disease activity indices
and both the patient’s and the physician’s global assessments, improved by the end of the treatment period.
Although the improvement was modest, it was statistically significant and was consistent across all measures.
We defined a priori a decrease of ⱖ4 points in
the mSELENA–SLEDAI score as a clinically important
change. This was achieved by more than one-half of the
patients (8 of 15). One-third of the patients also met the
more stringent criteria of a decrease of ⱖ7 points, which
was recently proposed by a consensus panel (23). The
slightly better response based on the mSELENA–
SLEDAI scores as compared with the SLAM scores
reflects differences in how the 2 indices weigh certain
manifestations of lupus, such as complete or partial
resolution of arthritis and resolution of (even mild)
hematuria or pyuria. Most of the changes occurred
during the first 6 weeks of the study and reached
IL-6 RECEPTOR BLOCKADE IN SLE
maximum levels by 12 week, with an increase in disease
activity occurring 4–8 weeks after the last treatment.
Of the individual manifestations of SLE, arthritis
improved the most, with complete resolution in 4 of the
7 patients who had arthritis at baseline. Five of the
patients enrolled in the study had renal involvement. All
had chronic glomerulonephritis characterized mainly by
proteinuria; this did not change during the study. Proteinuria is multifactorial at this stage, with a significant
contribution of noninflammatory processes, such as hemodynamic abnormalities and fibrosis, which may not be
altered by IL-6 receptor blockade or may require more
time to respond. Although we have seen some improvement in urinary sediment, the number of patients with
active sediment at baseline and the short duration of the
study prevent our drawing any conclusion about the
potential efficacy of tocilizumab in lupus nephritis.
One of the major biologic actions of IL-6 is its
ability to stimulate B lymphocyte differentiation into
immunoglobulin-secreting cells. Notably, we observed a
statistically significant decrease in circulating plasma
cells during treatment, as well as a significant decline in
anti-dsDNA antibody levels. This change seems to be
specific, since levels of other autoantibodies did not
change and since there was only a small, albeit statistically significant, decrease in total IgG levels. The clinical
significance of the decrease in anti-dsDNA antibody
levels is unclear, but these results are consistent with
previous ex vivo observations that IL-6 blockade may
alter the B cell abnormalities found in lupus.
There are limitations to our study. First, the
3-month treatment period is too short to allow an
estimation of the long-term toxicities of tocilizumab in
SLE. Second, we excluded patients who were receiving
concomitant immunosuppressive agents, and thus, this
study may not reflect everyday practice. Third, given the
open-label design and the lack of a control group, all
efficacy data should be considered preliminary. Fourth,
because of the small number of patients, we could not
make formal comparisons among the 3 dosage groups.
However, our data suggest that neutropenia is more
severe in those taking 8 mg/kg of tocilizumab; therefore,
future studies should consider evaluating doses equivalent to 4 mg/kg administered every 2 weeks.
This pilot study provides the first data that tocilizumab can effectively block IL-6 in patients with SLE.
The improvements in markers of inflammation as well as
in the clinical and serologic manifestations of lupus
activity are encouraging and should be explored further
in controlled studies of tocilizumab.
551
ACKNOWLEDGMENTS
We would like to thank Drs. Larissa Lapteva and Sarah
Okada for their assistance with patient evaluations, Ms Margaret Brown and Tuyet-Hang Pham for their technical assistance, and the Nursing Staff of the NIH Clinical Center 5SW
Day Hospital for their dedicated care of the patients.
AUTHOR CONTRIBUTIONS
All authors were involved in drafting the article or revising it
critically for important intellectual content, and all authors approved
the final version to be published. Dr. Illei had full access to all of the
data in the study and takes responsibility for the integrity of the data
and the accuracy of the data analysis.
Study conception and design. Illei, Tackey, Takeda, Balow, Lipsky.
Acquisition of data. Illei, Yarboro, Daruwalla, Tackey, Fleisher,
Balow.
Analysis and interpretation of data. Illei, Shirota, Lipsky.
ROLE OF THE STUDY SPONSOR
This study was supported by the Intramural Research Program of the National Institute of Arthritis and Musculoskeletal and
Skin Diseases (National Institutes of Health) and by Chugai Pharmaceutical Company, Ltd. under a Cooperative Research and Development Agreement. Chugai Pharmaceutical Company, Ltd. was involved
throughout the process of the study design, data acquisition and
analysis, and manuscript preparation. Publication of this article was
not contingent upon approval by Chugai Pharmaceutical Company,
Ltd.
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