Long-term efficacy and safety of erenumab in Japanese patients with episodic and chronic migraine: results from a 28-week open-label treatment period of a randomised trial

Abstract

Objectives To evaluate the 1-year efficacy and safety of once-monthly erenumab 70 mg following a 24-week double-blind treatment period (DBTP) of a phase III randomised study of Japanese patients with episodic migraine (EM) or chronic migraine (CM).Design Multicentre open-label study.Setting A total of 41 centres in Japan.Participants Patients completing the DBTP continued into the 28-week open-label treatment period (OLTP). 254 of 261 (97.3%) randomised patients continued into the OLTP; 244 (93.5%) completed treatment.Interventions Once-monthly subcutaneous erenumab 70 mg.Main outcome measures Changes from baseline in monthly migraine days (MMD) and monthly acute migraine-specific medication treatment days (MSMD) reported via patient eDiary; proportion of ≥50% and ≥75% responders in MMD reduction from baseline; incidence and exposure-adjusted incidence of treatment-emergent adverse events (TEAEs).Results At week 24 of the DBTP, the mean (SE) change from baseline in MMD for the erenumab group was –3.8 (0.4) days (EM, –3.0 (0.4); CM, –5.2 (0.8)); in MSMD, –2.6 (0.4) days (EM, –2.1 (0.4); CM, –3.4 (0.7)). At the end of the OLTP (52 weeks postbaseline), the mean (SE) change from baseline in MMD was –4.7 (0.3) days (EM, –3.4 (0.3); CM, –6.9 (0.6)); in MSMD, –3.3 (0.3) days (EM, –2.4 (0.3); CM, –4.6 (0.5)). The proportion of ≥50% responders for MMD reduction in the erenumab group was 34.1% at week 24; 44.4% at week 52. The exposure-adjusted incidence of TEAEs was 219.7 per 100 patient-years during the OLTP (DBTP, 251.0 for the erenumab group). The most common TEAEs during the OLTP were nasopharyngitis, constipation and influenza. No new safety concerns were identified.Conclusions Erenumab treatment was associated with reduced migraine frequency in Japanese patients with EM or CM for up to 1 year. Overall safety results from the OLTP were consistent with DBTP results.Trial registration number NCT03812224.