Biohaven says oral migraine drug set for 2019 filing, but data disappoints

Biohaven on NYSE screens
Biohaven listed on the Nasdaq last year. (Biohaven)

Biohaven says it has two positive phase 3 trials in hand for its oral CGRP inhibitor for migraine, setting up a filing next year, although investors seemed to be spooked by the data.

The Connecticut biotech is in a race with Allergan to bring the first orally active drug in the CGRP class to market and, with two phase 3 trials for rimegepant showing a significant improvement versus placebo, looks to have sneaked ahead of main rival Allergan, which reported data from its first phase 3 trial of oral CGRP drug ubrogepant last month.

Allergan has yet to get a readout in a confirmatory trial but has said it is also scheduling an FDA filing in 2019.

Biohaven said today that its two trials both showed that a single dose of rimegepant was superior to placebo when it came to providing relief from pain or another most bothersome symptom two hours after dosing, with fewer patients on the active drug requiring rescue therapy with current drugs such as triptans.

All told, a little over 19% of patients on rimegepant were pain-free at that time point, compared to 14% of the placebo group, with the difference between the two groups appearing to get wider beyond two hours. Similarly, around 37% of patients were free of their most bothersome symptom (MBS) compared to around a fourth of subjects in the control arm.

That meant the trials hit their primary endpoints, but nevertheless shares in the company fell around a third immediately after the news, suggesting investors weren’t impressed with the results, although they had started to recover a little at the time of writing.

For comparison, around 20% of patients on ubrogepant were pain-free at two hours, compared to 12% in the placebo cohort. Meanwhile, Allergan’s drug alleviated the MBS in around 38% of cases, compared to 28% for control.

Biohaven has been quick to highlight that rimegepant looked clean when it came to causing an increase in liver enzyme levels—something that was seen in a few patients in the ubrogepant phase 3 trial.

The efficacy results for the two drugs don’t look a million miles apart, so the reaction may reflect skepticism that the oral CGRPs will struggle to make their mark against injectable CGRPs for migraine prevention that could be approved this year. That group includes Novartis and Amgen’s Aimovig (erenumab), which looks to be in pole position at the moment with an FDA verdict imminent, as well as Teva’s fremanezumab and Eli Lilly’s galcanezumab, which could hear from the regulator later this year.

Biohaven needs rimegepant to be a success, particularly as just a few months ago it was hit hard when its former lead drug trigriluzole for the rare neurodegenerative disease spinocerebellar ataxia failed a late-stage trial.

Biohaven CEO Vlad Coric, M.D., said in a statement that the data show rimegepant combines “positive efficacy results and a favorable safety profile with ease of oral dosing,” adding: “We believe that rimegepant will represent a significant improvement over existing treatment options.”