Long-term tolerability and nonvascular safety of erenumab, a novel calcitonin gene-related peptide receptor antagonist for prevention of migraine: A pooled analysis of four placebo-controlled trials with long-term extensions

Background Efficacy and safety of erenumab have been evaluated in a comprehensive clinical development program resulting in approval for migraine prevention in over 40 countries to date. Methods This integrated safety analysis included four double-blind randomized trials and their extensions (up to three-plus years). Safety endpoints included exposure-adjusted patient incidences of adverse events, serious adverse events, and anti-erenumab antibodies. Results In all, 2375 of the patients randomized across the four studies received at least one dose of erenumab (70 mg or 140 mg), with cumulative exposure of 2641.2 patient-years. Exposure-adjusted adverse event rates during the double-blind treatment phase were similar to placebo, with the exception of injection-site reactions (17.1 vs. 10.8 per 100 patient-years), constipation (7.0 vs. 3.8 per 100 patient-years), and muscle spasm (2.3 vs. 1.2 per 100 patient-years). During the long-term extensions, adverse events reported were similar to those observed during the double-blind treatment phase, and rates of injection site reactions, constipation, and muscle spasm were reported at lower rates than in the double-blind treatment phase. There were two deaths reported, both confounded by pre-existing conditions. Conclusions This pooled safety analysis revealed a favorable and stable adverse event profile over time for erenumab with more than three years of exposure.