A Phase III clinical trial (REGAIN) revealed that long-term galcanezumab (a humanized monoclonal antibody) therapy has a good tolerability and safety profile in people suffering from chronic migraine. Amnon Mosek et al. aimed to determine galcanezumab's long-term safety for migraine management.

Patients (18-65 years of age) having chronic migraine who accomplished REGAIN study, including a nine-month open-label intervention period and a four-month post-intervention washout were eligible for the study. Participants exhibited a gap of around 5-13 months from their last study dose prior to initiation of the 3-year continuous access program. Open-label galcanezumab was given to all participants at either 120 mg/month (1 injection) or 240 mg/month (two 120-mg injections).

If warranted, the researchers were allowed to resume the intervention with a 240 mg loading dose. The investigators and the patients remained blinded to former intervention assignments. The incidence of treatment-emergent adverse events (TEAEs), discontinuation due to AEs (DCAEs) and serious AEs (SAEs) were the endpoints ascertained. Overall, 29 participants who completed the REGAIN trial were incorporated in this analysis.

The continuous access program was completed by 86.2% of patients (n = 25). The maximum exposure duration to galcanezumab was found to be around 41 months. Notably, 62.1% participants (n = 18) reported ≥1 TEAE. During the continuous access program (n = 2, 7% each), the most commonly reported TEAEs were urticaria, pruritus, oropharyngeal pain, nausea, headache, gastritis, cough, and COVID-19. No DCAEs were reported during the program.

Notably, 20.7% participants (n = 6) reported SAEs which were not treatment-associated. A high rate of completion was seen after up to 3 years of intervention. Galcanezumab exhibited a favorable safety profile and was well-tolerated. The safety and tolerability profile showed consistency with other preventive long-term intervention studies of migraine.