In 45 Japanese migraine patients (60% switching from other CGRP mAbs, 67% with 4+ prior preventive failures), 85% achieved at least 30% reduction in monthly migraine days over 6 months of erenumab, though switchers took longer (4-6 months) to respond.
85% cumulative responseOver 6 months, 85% of highly treatment-resistant Japanese migraine patients achieved at least 30% reduction in monthly migraine days with erenumab
What the researchers found
Cumulative 85% response rate (≥30% MMD reduction) over 6 months. Response rates: 36% at 1 month, 47% at 3 months, 63% at 6 months. CGRP mAb-naïve: 56% early responders. CGRP mAb-switching: 26% early responders, 59% late responders. Wearing-off (increased migraines week 2→4): 2.4-12.5%. Only 11.1% had adverse events (all mild).
Why it matters
This study demonstrates that erenumab works in highly treatment-resistant patients and those switching from other CGRP antibodies — two populations with limited real-world data, especially in Asian populations. The finding that switchers need 4-6 months to respond has direct clinical implications for treatment evaluation timelines.
The numbers in context
45 patients. 60% switching from other CGRP mAbs. 66.7% had ≥4 prior prophylaxis failures. 6-month follow-up.
How the study worked
Single-center 6-month prospective cohort of 45 Japanese migraine patients treated with erenumab. Monthly migraine days tracked. Early (1-3 months) and late (4-6 months) responder patterns analyzed. Wearing-off assessed by comparing weekly migraine days between weeks 2 and 4 of each month.
Who was studied
Japanese patients with episodic or chronic migraine
What this study cannot tell us
Small sample (45 patients), single-center, non-controlled. Asian-specific findings may not generalize. The 30% response threshold is a relatively low bar. No standardized reason for switching documented. Japanese erenumab dosing may differ from Western practice.
How to read the evidence
Rated moderate: prospective cohort with clear outcome measures, but small sample (45 patients), single-center, and uncontrolled.
When this study was published
Published in 2024. Provides real-world Asian data for a drug class with limited non-Western evidence.
The bigger picture
As CGRP antibodies become standard migraine care, understanding switching patterns and response timelines is critical. This study shows that even in heavily pretreated patients, erenumab can work — but patience is needed, especially when switching between CGRP antibodies.
Questions still open
- Why do CGRP mAb switchers take longer to respond to erenumab — is there a pharmacological explanation?
- Would extending the evaluation period beyond 6 months capture additional late responders?
- Is the wearing-off phenomenon clinically significant enough to consider dosing adjustments?
Common questions
If one CGRP migraine drug fails, can switching to erenumab still help?
How long should you try erenumab before deciding if it works?
Read the original research
Real-world effectiveness of erenumab in Japanese patients with migraine.
Heliyon, 10(4), e26568
Citation
Suzuki, Keisuke; Suzuki, Shiho; Shiina, Tomohiko; Haruyama, Yasuo; Kobayashi, Saro; Shioda, Mukuto; Hirata, Koichi. (2024). Real-world effectiveness of erenumab in Japanese patients with migraine.. Heliyon, 10(4), e26568. https://doi.org/10.1016/j.heliyon.2024.e26568