Background: Evolocumab, a fully human monoclonal antibody to PCSK9 (proprotein convertase subtilisin/kexin type 9), markedly reduces low-density lipoprotein cholesterol across diverse patient populations. The objective of this study was to assess the safety and tolerability of evolocumab in a pooled safety analysis from phase 2 or 3 randomized and placebo or comparator-controlled trials (integrated parent trials) and the first year of open-label extension (OLE) trials that included a standard-of-care control group.

Methods: This analysis included adverse event (AE) data from 6026 patients in 12 phase 2 and 3 parent trials, with a median exposure of 2.8 months, and, of those patients, from 4465 patients who continued with a median follow-up of 11.1 months in 2 OLE trials. AEs were analyzed separately for the parent and OLE trials. Overall AE rates, serious AEs, laboratory assessments, and AEs of interest were evaluated.

Results: Overall AE rates were similar between evolocumab and control in the parent trials (51.1% versus 49.6%) and in year 1 of OLE trials (70.0% versus 66.0%), as were those for serious AEs. Elevations of serum transaminases, bilirubin, and creatine kinase were infrequent and similar between groups. Muscle-related AEs were similar between evolocumab and control. Neurocognitive AEs were infrequent and balanced during the double-blind parent studies (5 events [0.1%], evolocumab groups versus 6 events [0.3%], control groups). In the OLE trials, 27 patients (0.9%) in the evolocumab groups and 5 patients (0.3%) in the control groups reported neurocognitive AEs. No neutralizing antievolocumab antibodies were detected.

Conclusions: Overall, this integrated safety analysis of 6026 patients pooled across phase 2/3 trials and 4465 patients who continued in OLE trials for 1 year supports a favorable benefit-risk profile for evolocumab.