A large-scale, pooled analysis of safety data from five Phase III clinical trials (including open-label extensions of two of these studies) and two Phase III open-label clinical trials of
efalizumab was conducted to explore whether
arthropathy adverse events (AEs) were associated with
efalizumab treatment in patients with moderate-to-severe chronic plaque
psoriasis. Data from patients who received
subcutaneous injections of
efalizumab or placebo were stratified for analysis into phases according to the nature and
duration of treatment. These included: the 'first treatment' phase (0-12-week data from patients who received either
efalizumab, 1 mg/kg once weekly, or placebo in the five placebo-controlled studies); the 'extended treatment' phase (13-24-week data from seven trials for all
efalizumab-treated patients); and the 'long-term treatment' phase (data from
efalizumab-treated patients who received treatment for up to 36 months in two long-term trials). Descriptive statistics were performed and the incidence of
arthropathy AEs per patient-year was calculated using 95% confidence intervals (CIs). During the first treatment phase, a similar proportion of patients had an
arthropathy AE in the
efalizumab group (3.3%; 58/1740 patients) compared with the placebo group (3.5%; 34/979 patients); the incidence of
arthropathy AEs per patient-year was 0.15 in the
efalizumab group (95% CI 0.11-0.19) and 0.16 in the placebo group (95% CI 0.11-0.22). Analysis of first treatment phase data from one study (n = 793) showed that the incidence of
psoriatic arthropathy per patient-year was lower in
efalizumab-treated patients (0.10; 95% CI 0.05-0.18) than in those given placebo (0.17; 95% CI 0.08-0.30). During the extended treatment phase, the incidence of
arthropathy remained low (0.17; 95% CI 0.14-0.22). Data from two long-term studies showed that there was no increase in the incidence of
arthropathy AEs over time in patients treated with
efalizumab for up to 36 months. Patients who had an
arthropathy AE during treatment with
efalizumab appeared to be more likely to have a history of
arthropathy prior to treatment.
Efalizumab does not appear to increase the risk of
arthropathy AEs compared with placebo.