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(497) Long-term treatment of chronic migraine with onabotulinumtoxinA: CLARITY pilot study

      Limited data exists on the durability of benefit for onabotulinumtoxinA treatment for chronic migraine patients beyond 5 cycles. Medical records were reviewed for patients with a confirmed diagnosis of chronic migraine per ICHD-III beta criteria with 15 or more headache (HA) days per month to evaluate the durability of benefit with onabotulinumtoxinA. Patients with at least 7 and up to 9 onabotulinumtoxinA injection cycles with an interval of 12 weeks (+/- 2 weeks) between injections were included in the analysis. Dosing must have been within the range of 155-195U using the PREEMPT injection paradigm.1 Abstracted data included dose, headache days, MIDAS, HIT-6, and adverse events. Thirty-three patients qualified with a minimum of 7 injection cycles. Of these patients, seventeen had 8 cycles and ten had 9 cycles. Mean HA days at baseline, cycles 7 and 9 were 19.08, 6.25 and 6.57, respectively. Mean HA free days at baseline, cycles 7 and 9 were 10.92, 23.75 and 23.43, respectively. The proportion of patients achieving >50% reduction in HA days at cycles 7 and 9 were 85% and 90%, respectively. The proportion of patients considered incapacitated based on MIDAS scores at baseline and cycle 7 were 53% and 12%, respectively. For HIT-6, 50% of patients had > 5 point reduction in score by cycle 7 compared to baseline. No serious adverse events were reported. Results suggest durability of benefit for onabotulinumtoxinA based on the reduction in HA days after 7 treatments, and through 9 treatments. OnabotulinumtoxinA demonstrated long-term improvements in migraine related disability as evaluated by the MIDAS and HIT-6 instruments. OnabotulinumtoxinA was well tolerated with no long term adverse events. Results warrant investigation in a larger study to better understand the durability of onabotulinumtoxinA in clinical practice for chronic migraine. (1. Blumenfeld A, Headache, 2010.) Study Supported by Allergan Inc.