Amgen has announced positive interim results from its open-label extension of the global Phase II, double-blind, placebo-controlled study evaluating the safety and efficacy of AMG 334 for the prevention of episodic migraine. Patients who entered the open-label phase received AMG 334 70 mg monthly and experienced a sustained reduction in monthly migraine days at week 52. The data were presented at the 57th Annual Scientific Meeting of the American Headache Society (AHS) on 19 June 2015, in Washington, D.C.
At one year, patients receiving AMG 334 70 mg experienced an average of a -4.9-day reduction from a baseline of 8.7 mean monthly migraine days, regardless of treatment received during the blinded phase. The 50% responder rate (greater than 50% reduction in monthly migraine days) was 62%at 52 weeks. Additional responder rates were reported for the first time: at 52 weeks the 75% responder rate was 38% and the 100% responder rate was 19%
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"These long-term data further demonstrate that AMG 334 provided meaningful benefit to these patients with fewer migraine days and more days with the ability to participate in work and social activities each month," said Sean E. Harper, executive vice president of R&D at Amgen. "The sustained safety and efficacy shown in this interim analysis adds to the growing body of evidence that reinforces the potential of AMG 334 for patients with this debilitating condition. We look forward to advancing the program to help fill an unmet need in migraine prevention."
The open-label portion of the Phase II study included 383 patients. All patients received AMG 334 70 mg starting at week 12 for up to 256 weeks. Safety and tolerability were evaluated monthly and this interim analysis includes data up to week 52. Additional efficacy endpoints included the change in monthly migraine-specific medication use days and patient-reported outcomes using the Migraine Disability Assessment (MIDAS) questionnaire.
Patients reported a nearly 50% reduction of monthly migraine-specific medication use days of -2 at 52 weeks, from a baseline of 4.3 days per month. In addition to clinical measures, patients self-reported the impact of headache and migraine on their daily activities. At one year, using the MIDAS tool, patients reported an improvement of approximately 12 days over the previous 3 months in their ability to function in work, home and social situations. According to the Migraine Research Foundation, migraine costs American employers more than $13 billion each year as a result of 113 million lost work days.
The safety and tolerability profile during the open-label phase was similar to that observed in the blinded phase of the study. The most commonly reported adverse events included fatigue, influenza, nasopharyngitis, arthralgia and back pain. No Grade 4 or 5 adverse events were reported. Serious adverse events were reported in 13 patients, one of which was deemed treatment-related. Less than 5% of patients discontinued the study during the open-label phase due to adverse events.
