Dive Brief:
- Biohaven Pharmaceutical Holding Co. Ltd. on March 26 announced positive results from two Phase 3 studies of its oral CGRP receptor antagonist rimegepant for the treatment of acute migraine. The company expects to file the drug for U.S. approval in 2019.
- In both trials, the drug met its co-primary endpoint of superiority over placebo on measures of pain freedom and freedom from bothersome symptoms at two hours post-dose.
- Despite meeting the studies' primary endpoints, the data was weaker than expected and sent shares of Biohaven down nearly 30% Monday morning to trade near $17 apiece.
Dive Insight:
The injectable CGRP class for prevention of migraine has been making headlines as those drugs near approval, but the race to advanced candidates for the acute treatment of migraine isn't that far behind.
Biohaven and Allergan plc are both developing oral drugs to stem headaches as they occur. Allergan also announced positive results from its Phase 3 study of its candidate ubrogepant in early February.
While the late-stage trials for the two drugs are not an apples-to-apples comparison, both analysts and investors are comparing the results anyway.
Analysts have focused on how quickly the drugs work and whether they cause the liver toxicity previously seen in past clinical development of small molecule CGRP antagonists by Merck & Co. and others.
In Biohaven's two studies, 19.6% and 19.2% of rimegepant patients achieved pain freedom, compared to 14.2% and 12% of the placebo groups. The magnitude of the treatment effect ranged from 5% to 22% across the investigations.
On the symptoms endpoint, 36.6% and 37.6% of rimegepant patients experienced symptoms freedom versus 27.7% and 25.2% for the placebo groups.
Those figures came in slightly below the mark set by Allergan's rival drug, according to a comparison compiled by Evercore ISI analyst Umer Raffat. Allergan reported slightly better numbers for the two doses in its first Phase 3 trial, but is conducting another Phase 3 at a lower dose. Biohaven is also conducting another late-stage study, but with a dissolvable formulation.
Raffat indicated in a note to clients that he's interested in whether the dissolvable tablet will help patients reach freedom from pain sooner than in the first two Phase 3 trials. A secondary endpoint in the current trials was time to pain freedom, which occurred about 30 to 45 minutes after taking rimegepant.
Allergan, though, has seen some cases of liver toxicity in its trial, while Biohaven reported none. Rimegepant's safety profile was similar to placebo.