The present study investigates the wearing-off effect in adults with chronic migraine treated with erenumab or fremanezumab.
This real-world observational study was based on pre-collected headache diaries from chronic migraine patients in treatment with either monthly injections of 140 mg of erenumab or 225 mg of fremanezumab. Consistent wearing-off was defined as an increase of ≥2 weekly migraine days in the last week compared to the second week over two consecutive 4-week treatment periods. The primary endpoint was wearing-off in the total population. The secondary endpoints were difference in wearing-off in (i) a subgroup of patients treated with erenumab and fremanezumab and (ii) consistent wearing-off in patients with a ≥30% reduction in monthly migraine days, compared to baseline, in the two consecutive treatment months.
In total, 100 patients (erenumab: n = 60, fremanezumab: n = 40) were included. Sixty-two out of 100 (62%) patients had consistent ≥30% treatment response on antibody therapy in both months (erenumab: n = 36, fremanezumab: n = 26). There was no consistent wearing-off over the two consecutive months from week 2 to week 4 (3.04%,  = 0.558). There was no wearing-off within the erenumab ( = 0.194) or the fremanezumab ( = 0.581) groups. Among the ≥30% treatment responders, there was no consistent wearing-off over the two consecutive months (2.6%,  = 0.573).
There was no wearing-off in treatment responders, which is in alignment with premarketing data from placebo-controlled phase III studies. These data suggest that patients should be informed upfront that no wearing-off effect is expected because anxiety for attacks at the end of the month may generate migraine attacks.