What happened

After reporting mixed results from the first of two phase 3 trials of its migraine drug, shares in Alder Biopharmaceuticals (NASDAQ:ALDR) are trading 26% lower today as of 3:16 p.m. EDT.

So what

Alder Biopharmaceuticals is developing eptinezumab to help prevent migraines. Today, the company unveiled data showing that it statistically and significantly lowered the number of monthly migraines in patients from the baseline. However, the benefit compared to placebo was less than hoped.

A man holds his head in despair while standing in front of a quote screen showing a declining stock price.

Image source: Getty Images.

Specifically, the 300-mg dose reduced the number of monthly migraine days by 4.3 days from an average of 8.6 days at baseline. The 100-mg dose reduced migraine days by 3.9 days. For comparison, placebo reduced monthly migraine days by 3.2 days, or about one day less than the 300-mg dose. 

Management also reported secondary data from the trial showing that an average of 20% of patients receiving the 300-mg dose were migraine free in a given month. For perspective, in a previous proof-of-concept clinical trial evaluating patients with frequent episodic migraines, complete migraine relief was observed in 27% to 41% of patients in any given month.

Now what

The placebo effect may have been higher in this trial than some anticipated, resulting in less of a gap between eptinezumab's efficacy and the performance of patients on placebo. The drop-off in migraine free patients in the secondary endpoint from the proof-of-concept trial isn't unexpected given this trial involved more patients. However, it does crimp optimism that this drug can differentiate itself from competitors, including Eli Lilly's (NYSE:LLY) galcanezumab.

Galcanezumab has the same mechanism of action as eptinezumab, and earlier this year, Eli Lilly reported phase 3 results from two trials evaluating its use in patients with episodic migraines. In those trials, galcanezumab reduced migraine days by about two more days per month than placebo.

Given eptinezumab's results failed to excite investors, attention now turns to Alder Biopharmaceuticals' ongoing phase 3 trial in chronic migraine. Results from that trial should be available in time to file for FDA approval (if results are positive) in the second half of 2018. However, Eli Lilly's galcanezumab already delivered a win in chronic migraine, and a filing for FDA approval of it in both episodic and chronic migraine is expected before the end of 2017.