Immunogenicity and skin clearance recapture in clinical studies of brodalumab

Background: Antidrug antibodies (ADAs) may change pharmacokinetic or pharmacodynamic profiles of biologic therapies, potentially decreasing efficacy. Objective: To evaluate the potential effects of brodalumab immunogenicity on safety, efficacy, and retreatment. Methods: Data from 1 phase 2 and 3 phase 3 studies of brodalumab in psoriasis were analyzed. Results: Overall, 2.7% of patients had positive test results for binding ADAs after receiving brodalumab; ADAs were transient in 1.4% of patients, and there were no neutralizing ADAs. Among ADA-positive patients, 60.0% (3/5) achieved a static physician's global assessment score of 0 or 1 at week 12 in the group receiving the brodalumab 210 mg every 2 weeks, compared with 79.1% (1131/1429) of ADA-negative patients. All patients (100%) who experienced return of disease and were retreated with brodalumab 210 mg every 2 weeks (none were ADA positive) achieved at least a 75% improvement in Psoriasis Area And Severity Index, >= 90% of whom regained response by week 8 of retreatment. Hypersensitivity reactions were less frequent with brodalumab than with placebo. Injection site reactions occurred in 1.8% of patients treated with brodalumab versus 2% of patients treated with ustekinumab. Limitations: Retreatment could be assessed in only 1 phase 3 brodalumab study. Conclusion: Brodalumab compares favorably with other biologics in terms of immunogenicity and high rates of efficacy recapture upon retreatment.