Effect of tocilizumab on neutrophils in adult patients with rheumatoid arthritis: pooled analysis of data from phase 3 and 4 clinical trials.

Objectives: To investigate changes in neutrophil count and occurrences of infection in RA patients treated with the IL-6 receptor-α inhibitor tocilizumab (TCZ). Methods: Data were pooled from patients who received i.v. TCZ (4 mg/kg + MTX, 8 mg/kg ± DMARDs, 10 mg/kg) or placebo + DMARDs in phase 3/4 clinical trials, long-term extensions or a pharmacology study. Neutrophil counts were measured routinely according to the Common Toxicity Criteria for Adverse Events grades; TCZ dosing was adjusted if necessary. Covariates associated with decreased neutrophil counts were assessed with multivariate regression analysis. Infection rates within 30 days of neutrophil count changes were calculated per 100 patient-years of TCZ exposure. Results: In placebo-controlled parts of trials, more TCZ-treated than placebo-treated patients had grade 1/2 or 3/4 neutrophil counts (TCZ: 28.2%/3.1%; placebo: 8.9%/0.2%). In placebo-controlled trials + long-term extensions, 4171 patients provided 16204.8 patient-years of TCZ exposure. Neutrophil counts decreased through week 6 from baseline [mean ( s . d .) change, -2.17 (2.16) × 10 9 /l) and remained stable thereafter. Rates (95% CI) of serious infections within 30 days of normal [4.66 (4.31, 5.03)], grade 1/2 [2.48 (1.79, 3.34)] and 3/4 [2.77 (0.34, 10.01)] neutrophil counts were similar. Baseline neutrophil count <2 × 10 9 /l and female gender were associated with grade 3/4 neutrophil counts [odds ratio (OR) (95% CI): 19.02 (6.76, 53.52), 2.55 (1.40, 4.66)]. Patients who stopped TCZ in response to decreased neutrophil count returned more quickly to normal levels than patients who reduced or continued their dose. Conclusion: Decreases in neutrophil counts in patients taking TCZ do not appear to be associated with serious infections and are normalized by current risk mitigation guidelines.

Effects of tocilizumab on neutrophil function and kinetics.

BACKGROUND: Decreases in circulating neutrophils (polymorphonuclear leucocytes, PMNs) have been reported in patients treated with the anti-interleukin-6 receptor (IL-6R) antibody tocilizumab (TCZ); the mechanism for this is unclear. We hypothesize that TCZ reduces circulating neutrophils by affecting margination and/or bone marrow trafficking without affecting neutrophil function or apoptosis. MATERIALS AND METHODS: Eighteen healthy subjects were randomized to single intravenous dose of TCZ 8 mg/kg (n = 12) or placebo (n = 6) on day 0. On day 4, each subject had autologous indium-111-labelled neutrophils re-injected, and their kinetics quantified with longitudinal profiling in a whole body gamma-counter. TCZ-treated subjects were divided into two groups according to the extent of reduction in neutrophil count. RESULTS: Mean day 4 neutrophil counts, as % baseline, were 101·9%, 68·3% and 44·2% in the placebo, TCZ-PMN-'high' and TCZ-PMN-'low' groups, respectively (P < 0·001). Following TCZ, neutrophil function, activation and apoptosis ex vivo were all unaffected. In vivo, there were no differences in early blood recovery or margination to liver/spleen and bone marrow; however, later neutrophil re-distribution to bone marrow was markedly reduced in the TCZ-PMN-low group (peak pelvic count as % day 4 count on: day 5, 188% placebo vs. 127% TCZ-PMN-low, P < 0·001; day 10, 180% placebo vs. 132% TCZ-PMN-low, P < 0·01), with a trend towards higher liver/spleen neutrophil retention. CONCLUSIONS: We have demonstrated for the first time in humans that IL-6R blockade affects neutrophil trafficking to the bone marrow without influencing neutrophil functional capacity.

Assessment of short-term symptomatic efficacy of tocilizumab in ankylosing spondylitis: results of randomised, placebo-controlled trials.

OBJECTIVES: BUILDER-1 and BUILDER-2 aimed to assess the efficacy and safety of tocilizumab (TCZ) in patients with ankylosing spondylitis (AS). METHODS: BUILDER-1 was a two part, phase II-III parallel-group trial in patients with AS naive to antitumour necrosis factor (aTNF) treatment. Patients in part 1 received TCZ 8 mg/kg or placebo for 12 weeks. In part 2 (beginning after part 1 enrolment ended), newly enrolled patients received TCZ 4 or 8 mg/kg or placebo for 24 weeks. The same treatment arms were used in BUILDER-2, a phase III study in aTNF-inadequate responders. The primary endpoint for both studies was the proportion of patients achieving 20% improvement in the Assessments in Axial SpondyloArthritis international Society (ASAS). Secondary and exploratory endpoints included ASAS40 response rates, Bath Ankylosing Spondylitis Disease Activity Index improvement, changes in joint counts, enthesitis score and C reactive protein (CRP). RESULTS: 102 patients were randomised in BUILDER-1 part 1; 99 (48 TCZ, 51 placebo) completed 12 weeks. Week 12 ASAS20 response rates were 37.3% and 27.5% in the TCZ and placebo arms, respectively (p=0.2823). Secondary and exploratory endpoints did not differ between treatment arms. CRP levels declined with TCZ treatment, suggesting adequate IL-6 receptor blockade. As a result, BUILDER-1 part 2 and BUILDER-2 were terminated. TCZ safety results were consistent with previous observations in rheumatoid arthritis, except for a cluster of anaphylactic and hypersensitivity events at Bulgarian study sites. No apparent explanation for this clustering could be found. CONCLUSIONS: BUILDER-1 failed to demonstrate TCZ efficacy in treating aTNF-naive patients with AS.

Neutropenia During Tocilizumab Treatment Is Not Associated with Infection Risk in Systemic or Polyarticular-course Juvenile Idiopathic Arthritis.

OBJECTIVE: To determine whether neutropenia is associated with increased risk for infection in patients with systemic juvenile idiopathic arthritis (sJIA) and polyarticular-course juvenile idiopathic arthritis (pcJIA) treated with tocilizumab (TCZ). METHODS: Data up to Week 104 from 2 phase III trials of intravenous TCZ in sJIA (n = 112; ClinicalTrials.gov, NCT00642460) and pcJIA (n = 188; ClinicalTrials.gov, NCT00988221) were pooled. Worst common toxicity criteria grade and lowest observed absolute neutrophil count (ANC) were identified for each patient. Associations between patient characteristics and lowest observed ANC were tested using univariate regression analysis. Infection and serious infection rates per 100 patient-years (PY) in periods associated with grades 1/2 and 3/4 neutrophil counts were compared with rates associated with normal neutrophil counts. RESULTS: ANC decreased to grade ≥ 3 in 25.0% and 5.9% of sJIA and pcJIA patients, respectively, and decreases were transient. Young age (p = 0.047) and methotrexate use (p = 0.012) were positively associated with neutropenia in patients with sJIA but not in patients with pcJIA. The rate of serious infections in patients with sJIA (10.9/100 PY; 95% CI 6.8-16.5) tended to be higher than in patients with pcJIA (5.2/100 PY; 95% CI 3-8.5). No increase in rates of serious or nonserious infections was observed during periods of neutropenia in either trial. CONCLUSION: Patients with JIA treated with TCZ experienced transient neutropenia that was not associated with an increased number of infections.

Malignancy rates in patients with rheumatoid arthritis treated with tocilizumab.

OBJECTIVE: To analyse malignancy rates in patients with rheumatoid arthritis (RA) treated with tocilizumab. METHODS: Patients who received tocilizumab or placebo+methotrexate/disease-modifying antirheumatic drugs in the double-blind phases of 5-phase three trials or who received at least 1 dose of tocilizumab in the long-term extension studies were analysed up to the 2 May 2012 cut-off date. Malignancies were monitored throughout the studies, analysed and adjudicated as malignant by medical review. Risk was compared with that in the general population using standardised incidence ratios (SIRs) based on data from the Surveillance Epidemiology and End Results SEER (US general population) and GLOBOCAN (non-US general population) databases. RESULTS: In total, 4009 patients in the tocilizumab all-exposure population were included. Mean treatment duration was 4.0 years (mean 5.1 (range 0.0-6.8); total observation time was 16 120.1 patient-years (PY). The adjudicated malignancy rate (95% CI) was 1.26/100 PY (1.09 to 1.44) and remained constant over time. The SIR (95% CI) for all malignancies combined, excluding non-melanoma skin cancer, was 1.36 (1.01 to 1.80) for US and 1.81 (1.44 to 2.23) for non-US populations, driven primarily by higher rates in lung and bronchus (US/non-US) malignancies and prostate cancer and non-Hodgkin lymphoma (non-US), in contrast to those for the general populations; these higher rates are in line with those expected in patients with RA or in the geographic regions studied. CONCLUSIONS: Malignancy rates remained stable with long-term tocilizumab treatment, and malignancy types and rates were consistent with those expected in patients with RA.

Tocilizumab in rheumatoid arthritis: a case study of safety evaluations of a large postmarketing data set from multiple data sources.

OBJECTIVES: To evaluate the magnitude of serious adverse events (SAEs) observed in postmarketing reports of tocilizumab (TCZ) for rheumatoid arthritis (RA) in relation to SAEs observed in TCZ clinical trials and external epidemiology data. METHODS: A total of 64,000 patient-years (PY) of TCZ exposure was needed to determine, with 90% power, whether rates of SAEs of interest (eg, death, hepatic, gastrointestinal, and cardiovascular) were ≥50% higher (agreed with the Food and Drug Administration) than expected. Reporting rates were calculated for spontaneously reported SAEs, open-label or unblinded postmarketing clinical trials (phase 3b/4), and a Japanese postmarketing surveillance program in the global postmarketing safety database. Event rates were calculated for the registrational placebo-controlled trials and long-term extension data. External comparators for anti-tumor necrosis factor (aTNF)-treated RA patients were derived from a US-based health care insurance claims database or published literature. RESULTS: The global postmarketing safety database provided 65,099 PY of TCZ exposure; the aTNF external comparator population provided 53,360 PY. Spontaneous reporting rates per 100 PY (95% confidence interval) were 8.3 (8.1, 8.5) SAEs, 0.39 (0.34, 0.44) deaths, 0.06 (0.04, 0.08) serious hepatic events, 0.15 (0.12, 0.18) serious gastrointestinal events, 0.09 (0.07, 0.12) serious myocardial infarctions, 0.15 (0.12, 0.18) serious strokes, and 0.07 (0.05, 0.09) cardiac deaths in the global postmarketing safety database. These were of similar magnitude to corresponding rates from registrational clinical trials, the aTNF external comparator population, and published literature. CONCLUSIONS: SAE rates observed among postmarketing TCZ users were similar to those of various comparison populations. Predetermined design of studies to compare postmarketing AEs using multiple data sources is a useful strategy that can be applied to other medications.