Timing and durability of response to erenumab in patients with episodic migraine.

Objective: We sought to evaluate temporal response patterns to erenumab treatment in patients with episodic migraine.

Background: Although many patients treated with erenumab experience onset of efficacy as early as 1 week, clinical benefits of migraine preventive therapies may accrue with continued treatment. Furthermore, details about the maintenance of clinical responses have not been reported.

Methods: This was a post hoc analysis of a 6-month, randomized, double-blind, placebo-controlled, phase 3 study of erenumab for the prevention of episodic migraine. We analyzed temporal responses to erenumab using a threshold of ≥50% reduction from baseline in monthly migraine days (MMDs).

Results: During the 6-month treatment period, 73.7% (230/312) and 79.6% (253/318) of patients in the erenumab 70 mg (n = 312) and 140 mg (n = 318) groups, respectively, achieved a response in at least 1 month. In this group of responders, at least half reached first monthly response (first month with ≥50% reduction from baseline in MMDs) by month 2 and at least 75% of them by month 3. The remainder responded in months 4-6. Of patients in the erenumab 70 and 140 mg groups, 35.3% (110/312) and 41.8% (133/318), respectively, responded over months 1-3 (mean response over first 3 months). Of these patients, 81.8% (90/110) and 81.9% (109/133) maintained this response over months 4-6 (mean response over last 3 months) in the 70 and 140 mg groups, respectively. Many patients who did not achieve an initial response (≥50% reduction from baseline in MMDs during month 1) responded later with continued treatment, with approximately one-half or more of initial nonresponders responding by months 4-6.

Conclusions: These results support guidelines recommending at least 3 months following the initiation of erenumab for migraine prevention before the assessment of response.