Long-term efficacy and safety during open-label erenumab treatment in Japanese patients with episodic migraine

Abstract

Objective: To assess long-term (up to 2 years) efficacy, tolerability, and safety of erenumab for the prevention of episodic migraine (EM) in Japanese patients.

Background: Previously published results from the double-blind treatment phase (DBTP) of a phase 2 clinical study have demonstrated the efficacy and safety of erenumab in Japanese patients with EM.

Methods: Patients completing the 24-week placebo-controlled DBTP could continue into the 76-week open-label treatment phase (OLTP), receiving erenumab 70 mg or 140 mg subcutaneously once monthly. The initial dose in the OLTP was erenumab 70 mg monthly, which was later changed to 140 mg. After study completion, the following were assessed: change from baseline in monthly migraine days (MMD), change from baseline in monthly acute migraine-specific medication days (MSMD), percentage of patients achieving ≥50% and ≥75% reduction in MMD, change from baseline in the 6-item Headache Impact Test (HIT-6™) score, and safety (exposure-adjusted patient-incidence of adverse events [AEs], calculated as number of patients per 100 patient-years).

Results: Of 475 patients enrolled in the DBTP, 459 (96.6%) continued in the OLTP. The mean (SD) MMD was 7.9 (2.3) at baseline with the overall change from baseline at week 100 of -2.9 (4.1) days. The monthly acute MSMD was 5.7 (2.8) at baseline with change from baseline at week 100 of -1.7 (3.7) days. The proportion of patients who achieved ≥50% and ≥75% reduction in MMD from baseline at week 100 was 177/398 (44.5%) and 94/398 (23.6%), respectively. The HIT-6™ score was 58.4 (5.4) at baseline with a change of -6.4 (8.2) at week 100. The exposure-adjusted patient-incidence of AEs during the OLTP was 207.1/100 patient-years for the combined erenumab group, similar to that observed for either erenumab (271.0/100 patient-years) or placebo (257.3/100 patient-years) during the DBTP, and no new safety signals were detected during the OLTP.

Conclusion: Long-term erenumab treatment in Japanese patients with EM demonstrated sustained efficacy for up to 2 years, with a safety profile similar to previous studies, supporting erenumab as a potential new therapy for EM prevention in Japan.

Keywords: Japanese; efficacy; episodic migraine; erenumab; long-term; safety.

Conflict of interest statement

Fumihiko Sakai has received consulting fees from Amgen Inc. Takao Takeshima and Yoshihisa Tatsuoka have nothing to disclose. Koichi Hirata has received royalties from Amgen, Astellas, Daiichi Sankyo, Eisai, Merck Sharp & Dohme, and Pfizer. Sunfa Cheng, Yotaro Numachi, Cheng Peng, Fei Xue, and Daniel D. Mikol are employees and stockholders of Amgen Inc.

© 2021 The Authors. Headache: The Journal of Head and Face Pain published by Wiley Periodicals LLC on behalf of American Headache Society.

Figures

FIGURE 1

Study design. Durations and number of patients are shown for the double‐blind and open‐label treatment phases. In the OLTP, patients remained on erenumab 70 mg monthly if they had started the OLTP and had completed their pre‐scheduled week 48 visit; the dose was increased from 70 to 140 mg monthly at the next visit for patients who started the OLTP but had not yet completed the week 48 visit; and erenumab 140 mg monthly was reserved for patients who were still in the DBTP and had not yet entered the OLTP at the time of protocol amendment approval. DBTP, double‐blind treatment phase; OLTP, open‐label treatment phase; QM, once monthly; SC, subcutaneous

FIGURE 2

Patient disposition. IP, investigational product; OLTP, open‐label treatment phase

FIGURE 3

Change (mean [SD]) from baseline in MMD. Efficacy in the DBTP is shown by the randomized dose groups. Efficacy in the OLTP is shown for the total population. DBTP, double‐blind treatment phase; MMD, monthly migraine days; OLTP, open‐label treatment phase; SD, standard deviation

FIGURE 4

Patients achieving ≥50% reduction from baseline in MMD. Efficacy in the DBTP is shown by the randomized dose groups. Efficacy in the OLTP is shown for the total population. DBTP, double‐blind treatment phase; MMD, monthly migraine days; OLTP, open‐label treatment phase

FIGURE 5

Patients achieving ≥75% reduction from baseline in MMD. Efficacy in the DBTP is shown by the randomized dose groups. Efficacy in the OLTP is shown for the total population. DBTP, double‐blind treatment phase; MMD, monthly migraine days; OLTP, open‐label treatment phase

FIGURE 6

Change (mean [SD]) from baseline in monthly acute MSMD. Efficacy in the DBTP is shown by the randomized dose groups. Efficacy in the OLTP is shown for the total population. DBTP, double‐blind treatment phase; MSMD, migraine‐specific medication days; OLTP, open‐label treatment phase; SD, standard deviation

FIGURE 7

Change (mean [SD]) from baseline in HIT‐6™ score. DBTP, double‐blind treatment phase; HIT‐6™, 6‐item Headache Impact Test; OLTP, open‐label treatment phase; SD, standard deviation