Lilly has reported mixed trial data for its experimental therapy galcanezumab, showing efficacy in patients with episodic cluster headaches but failing in those with chronic cluster headache.

The drug demonstrated statistically significant differences in the reduction of weekly cluster headache attacks compared to placebo across weeks one to three of the two-month, double-blind treatment period.

A significantly greater percentage of patients treated with galcanezumab also achieved at least a 50 percent reduction in weekly cluster headache attacks compared to placebo at Week 3, the gated secondary endpoint, the firm noted.

On the safety side, the drug’s profile was consistent with previous studies testing its effectiveness for migraine prevention, with 8 percent of patients discontinuing treatment during the study versus 21 percent of those given a placebo.

Four percent of patients treated with galcanezumab stopped treatment during the study due to adverse events compared to 2 percent of patients treated with placebo.

"The positive results in episodic cluster headache are truly a landmark moment - both for people living with cluster headache and for our researchers at Lilly, many of whom have spent more than two decades researching and developing innovative, non-opioid treatment options for diseases like migraine and cluster headache,” said Christi Shaw, president of Lilly Bio-Medicines.

Based on the data, Lilly said it is now working with regulatory agencies around the world to determine the best path forward to getting the drug approved for episodic cluster headache, which represents 85 to 90 percent of cluster headache cases.

On the downside, a trial assessing galcanezumab in chronic cluster headache – which accounts for 10 to 15 percent of cluster headache cases – failed to meet its efficacy target.

The drug is a monoclonal antibody designed to bind to and inhibit the activity of calcitonin gene-related peptide (CGRP), already under review in the US as a potential treatment for migraine.