Biohaven announced positive top-line results from both of its two Phase 3 clinical trials (BHV3000-301 and BHV3000-302) of rimegepant (formerly known as BHV-3000), an oral CGRP receptor antagonist for the acute treatment of migraine. In each trial, rimegepant met the co-primary efficacy endpoints of superiority to placebo, at two hours post-dose, on pain freedom and freedom from the most bothersome symptom (MBS). Even without additional rimegepant dosing, or use of rescue medications, these studies showed an early separation from placebo and a profile of continued improvement over the dosing interval. Overall, efficacy and safety results were consistent across both Phase 3 trials.
Pain freedom at 2 hours for rimegepant treated subjects in Study 301 and 302 was 19.2% and 19.6%, respectively, versus 14.2% (p < 0.03) and 12.0% (p < 0.001) in the placebo treated groups. The magnitude of the treatment effect over placebo at 2 hours or later, as shown in the curves, ranged from 5% to 19% in Study 301 and 7% to 22% in Study 302. This continued improvement in pain freedom was observed in subjects who took a single dose of rimegepant without use of rescue medications.
Patients treated with rimegepant also achieved statistically significant benefits, as compared to placebo at 2 hours post-dose, in freedom from the MBS (selected from photophobia, phonophobia or nausea). Freedom from the MBS for rimegepant treated subjects in Study 301 and 302 were 36.6% and 37.6%, respectively, versus 27.7% (p < 0.002) and 25.2% (p < 0.0001) for placebo.
In addition to efficacy observed on the co-primary registrational endpoints, onset of pain relief (defined as transitioning from moderate-to-severe pain to either no-pain or mild-pain) was observed early after rimegepant treatment with numerical separation evident between 30-45 minutes post-dosing. By two hours in both studies, after a single dose, pain relief was achieved in over 55% of rimegepant treated subjects. Pain relief is a clinically important secondary endpoint, often associated with reduced disability due to migraine attacks.
Subjects with difficult-to-treat migraines, as defined by the need for prophylactic treatments including Botox, achieved improvements similar to the overall population in pain freedom, MBS, and pain relief at 2 hours.
Rimegepant was found to be both safe and well-tolerated in the two Phase 3 studies with a safety profile similar to placebo. In particular, pooled liver function test (LFT) results showed that rimegepant was no more likely than placebo to increase aminotransferase (ALT or AST) levels above the upper limit of normal (ULN). One patient treated with placebo and one patient treated with rimegepant showed LFTs > 3x ULN. No patients in either trial showed LFT elevations > 5x, > 10x or > 20x ULN. No patients in either trial experienced elevations in bilirubin > 2x ULN. No single adverse event (AE) occurred with an incidence higher than 2% and overall AE rates in the rimegepant group were similar to placebo. The most common AEs (pooled analysis across both studies) seen in patients treated with rimegepant were similar to placebo (nausea 1.4% and 1.1%, respectively; UTI 1% and 0.7%, respectively).
"The topline data from our two pivotal trials show that a single, oral dose of rimegepant has the potential to be an effective and safe acute treatment for migraine, addressing both pain and most bothersome symptoms without the need for repeat dosing or rescue medicines,” Vlad Coric, M.D., Chief Executive Officer of Biohaven, said. “By combining positive efficacy results and a favorable safety profile with ease of oral dosing, we believe that rimegepant will represent a significant improvement over existing treatment options. We thank the patients, investigators and dedicated Biohaven employees who have worked so hard to advance this drug candidate to this important milestone."
Acute attacks of migraine can differ in intensity and frequency, with many being highly disabling. More than 90% of migraine sufferers are unable to work or function normally during an attack. CGRP receptor antagonists represent a novel class of drug candidates for the treatment of migraine and are the first new class specific to the acute treatment of migraine in over 25 years. This unique and specific mode of action potentially offers an alternative to current agents. In addition, CGRP receptor antagonists could be appropriate for those who have contraindications to the use of triptans, such as patients with underlying cardiovascular diseases, or for those nonresponsive to current migraine therapies.
The patient demographics for Study 301 and Study 302 show that the population studied in these trials is representative of the typical migraine clinical population.