Benefits Beyond Headache Days With OnabotulinumtoxinA Treatment: A Pooled PREEMPT Analysis

INTRODUCTION: The double-blind, phase 3 PREEMPT trials demonstrated the efficacy and tolerability of onabotulinumtoxinA for headache prevention in adults with chronic migraine. This post hoc analysis evaluated the effect of onabotulinumtoxinA on clinically meaningful changes in headache severity, headache-related impact, and quality of life. METHODS: Pooled, 24-week data were used to determine percentages of patients meeting responder criteria for the change in headache days (≥ 50% reduction in headache-day frequency), Headache Impact Test (HIT-6; ≥ 5-point improvement), MSQ Role Function-Restrictive (MSQ-RFR; ≥ 10.9-point improvement), and Average Daily Headache Severity (ADHS; ≥ 1-point improvement on a 4-point ordinal scale [0 = no pain, 3 = severe pain]). RESULTS: In the pooled analysis population (N = 1384; onabotulinumtoxinA, n = 688; placebo, n = 696), significantly more patients treated with onabotulinumtoxinA compared with placebo were responders on HIT-6 (40.8 vs. 25.3%), MSQ-RFR (59.0 vs. 40.2%), and ADHS (35.5 vs. 22.4%) measures, and achieved traditional ≥ 50% reduction in headache days (44.8 vs. 34.2%; all P < 0.001). At least one responder criterion was met by 72.1% and 56.6% of onabotulinumtoxinA- and placebo-treated patients, respectively; all four were met by 20.4% and 8.6%, respectively (P < 0.001). Linear regression analysis showed that approximately 20% of the variance in HIT-6 and MSQ-RFR improvement was explained by improvement in headache days. CONCLUSIONS: Treatment with onabotulinumtoxinA for 24 weeks was associated with clinically meaningful benefits beyond reduction in headache days; including reductions in headache severity and headache-related impact, and improved quality of life. While 45% of patients met responder criteria for monthly headache days, over 70% had clinically meaningful improvements on at least one outcome measure. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT00156910 (PREEMPT 1) and NCT00168428 (PREEMPT 2)