Use of Most Bothersome Symptom as a Coprimary Endpoint in Migraine Clinical Trials: A Post‐Hoc Analysis of the Pivotal ZOTRIP Randomized, Controlled Trial

OBJECTIVE: To better understand the utility of using pain freedom and most bothersome headache‐associated symptom (MBS) freedom as co‐primary endpoints in clinical trials of acute migraine interventions. BACKGROUND: Adhesive dermally applied microarray (ADAM) is an investigational system for intracutaneous drug administration. The recently completed pivotal Phase 2b/3 study (ZOTRIP), evaluating ADAM zolmitriptan for the treatment of acute moderate to severe migraine, was one of the first large studies to incorporate MBS freedom and pain freedom as co‐primary endpoints per recently issued guidance by the US Food and Drug Administration. In this trial, the proportion of patients treated with ADAM zolmitriptan 3.8 mg, who were pain‐free and MBS‐free at 2 hours post‐dose, was significantly higher than for placebo. METHODS: We undertook a post‐hoc analysis of data from the ZOTRIP trial to examine how the outcomes from this trial compare to what might have been achieved using the conventional co‐primary endpoints of pain relief, nausea, photophobia, and phonophobia. RESULTS: Of the 159 patients treated with ADAM zolmitriptan 3.8 mg or placebo, prospectively designated MBS were photophobia (n = 79), phonophobia (n = 43), and nausea (n = 37). Two‐hour pain free rates in those with photophobia as the MBS were 36% for ADAM zolmitriptan 3.8 mg and 14% for placebo (P = .02). Corresponding rates for those with phonophobia as the MBS were 14% and 41% (P = .05). For those whose MBS was nausea, corresponding values were 56% and 16%, respectively (P = .01). Two‐hour freedom from the MBS for active drug vs placebo were 67% vs 35% (P < .01) for photophobia, 55% vs 43% (P = .45) for phonophobia, and 89% vs 58% for nausea (P = .04). MBS freedom but not pain freedom was achieved in 28%. Only 1 patient (1%) achieved pain freedom, but not MBS freedom. The proportion with both pain and MBS freedom was highest (56%) among those whose MBS was nausea. CONCLUSION: In this study, the use of MBS was feasible and seemed to compare favorably to the previously required 4 co‐primary endpoints.