Safety of Reslizumab in Uncontrolled Asthma with Eosinophilia: A Pooled Analysis from 6 Trials

Background: Intravenous reslizumab, a monoclonal IL-5 antibody, is approved for treating severe asthma with eosinophilia. Limited structured information is available on the safety of reslizumab in larger populations. Objective: To investigate the safety profile of intravenous reslizumab 3.0 mg/kg by analyzing data from 6 asthma clinical trials: 5 placebo-controlled (duration ≤52 weeks) and 1 open-label extension (up to 2 years of treatment). Methods: Patients were aged 12 to 75 years with inadequately controlled asthma with eosinophilia. In the placebo-controlled trials, 730 patients received placebo and 1028 received reslizumab 3.0 mg/kg. Results: Adverse events (AEs) and serious AEs occurred in higher percentages of patients in the placebo group (81% and 9%) than in the reslizumab group (67% and 6%). Asthma, nasopharyngitis, and upper respiratory tract infection were the most common AEs with placebo and reslizumab. Three cases of anaphylaxis, related to reslizumab, were successfully managed with standard therapies. No significant difference in the incidence of malignancies was seen when compared with placebo or the general population. Among 756 patients with more than 12 months of reslizumab exposure, the AE rate was lower than in the placebo-controlled trials (367.3 vs 433.9 events/100 patient-years). The incidence of AEs in patients on treatment for more than 12 months was no higher than in patients with shorter treatment durations. Conclusions: This analysis confirms that treatment with intravenous reslizumab for more than 12 months is well tolerated in patients with asthma, with no evidence of rare safety events that were not detected in individual trials.