Onset of action in placebo-controlled migraine attacks trials: A literature review and recommendation

Background Migraine patients want acute treatment to provide complete relief of the migraine attack within 30 minutes. Traditionally, “speed of onset of effect” is evaluated by estimating the time-point for first statistical separation of drug and placebo. The estimated onset of effect can be a few percent difference of patients being pain free in very large randomised, controlled trials. This difference, however, can be clinically irrelevant. Methods Placebo-controlled randomised, controlled trials with pain freedom results from 30 min to 2–4 hours were retrieved from the literature. For each time-point, the therapeutic gain (drug minus placebo) (TG) was calculated. Therapeutic gain for being pain free of 5% was chosen for the definition of “onset of action”, since this is approximately 1/3 of the 16% TG and 1/4 of 21% of TG for sumatriptan 50 mg and 100 mg, respectively. Results A total of 22 time-effect curves based on randomised, controlled trials were analysed. Based on the “onset of action” of 5% pain freedom, the evaluated drugs and administration forms can be classified as follows: i) Early time to onset, ≤30 min (three randomised, controlled trials); ii) medium time to onset, 60 min (nine randomised, controlled trials); iii) delayed time to onset, 90–120 min (10 randomised, controlled trials). Conclusion Only three non-oral administration forms with a triptan (subcutaneous sumatriptan and nasal zolmitriptan) resulted in an “onset of action” at ≥30 min; in the future, early onset of action should be a priority in the development of new drugs or new administration-forms for the treatment of acute migraine attacks.