SAN DIEGO — However, the drug met secondary outcomes of reduction in weekly attacks, mean change in baseline pain, and Patient Global Impression of Change (PGIC) score.
Eptinezumab is the latest of multiple anti–calcitonin gene-related peptide (CGRP) therapies to fail in the clinic against episodic cluster headache, all using weekly attacks as a primary endpoint, though therapies also scored positive results for secondary endpoints, according to Stewart Tepper, MD, who presented the study results at the annual meeting of the American Headache Society
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Dr. Stewart J. Tepper
Eptinezumab is already approved for migraine, and is fully bioavailable by the end of an infusion. “That was why we thought this might be a really interesting treatment for prevention of cluster headache,” said Dr. Tepper, who is VP of external research at the New England Institute for Neurology and Headache in Stamford, Connecticut.
Are We Looking at the Wrong Endpoint?
Secondary endpoints offered more encouragement. “For each week, the eptinezumab looked either numerically higher than the placebo or nominal statistical significance was achieved. By week 4, two-thirds of the patients had at least a 50% reduction in their number of weekly cluster attacks. Then the average pain intensity for the day and the patient global impression of change were all in favor of eptinezumab. That made us interested in whether we’re missing something, whether this is maybe not the correct endpoint to be looking at,” said Dr. Tepper.
He suggested that it may be time for the Food and Drug Administration (FDA) to reconsider the endpoints used in clinical trials for cluster headaches.
Study criteria included cluster periods that lasted at least 6 weeks, and at least 1 year since the diagnosis of episodic cluster headache. The study enrolled patients who were out of their cluster period, who underwent a second screening of 7-14 days after they entered a new cycle. After that, they were randomized to an injection of placebo or 400 mg eptinezumab, and followed for 4 weeks. After 4 weeks, all patients received an injection of 400 mg eptinezumab and placebo patients were crossed over to eptinezumab and followed out to 24 weeks.
The study population included 231 patients (78% male; mean age, 44 years), with a mean of 2.7 cluster headache attacks per day an average duration of 62 minutes per attack. The worst pain was reported as excruciating in 59% of participants.
The mean change in number of weekly attacks in weeks 1 and 2, compared with baseline, was not statistically significant (–4.6 with eptinezumab, –4.6 with placebo; P = .5048). More patients in the eptinezumab group had a 50% or greater reduction in attack frequency in weeks 3 (50.9% vs 37.3%; P < .05), week 3 (62.5% vs 43.8%; P < .01), and week 4 (66.7% vs 50.5%; P < .01). The difference in mean change in pain from baseline became statistically significant at week 3 and 4 (P < .01). There were also statistically significant differences in PGIC score at weeks 1, 2, and 4. The frequency of any treatment-emergent adverse event was similar in the eptinezumab and placebo groups (25.0% vs 26.5%), and only one led to treatment withdrawal in the eptinezumab group (0.9%).