Biohaven flunks first clinical test for rare disease drug post-Pfizer sell-off

In its first clinical test since Pfizer calved off a chunk of the company, Biohaven has come up short. 

Biohaven reported that troriluzole has failed a phase 3 trial in spinocerebellar ataxia, just weeks after CEO Vlad Coric, M.D., touted the company's future as a slimmed-down R&D engine after the migraine business was sold off to Pfizer for $11.6 billion.

The trial results take the wind out of the company’s sails, which had hoped to replicate the success of the commercial migraine med Nurtec ODT. Instead, an unexpected lack of disease progression among trial participants over the nearly one-year follow-up period hindered the impact of the drug.

However, Coric said that the company looked forward to sharing genotype data with regulators and “working with the FDA to address the high unmet need in this patient population," according to a Monday statement. 

The double-blind, randomized trial recruited 213 patients with spinocerebeller ataxia and assessed disease progression over 48-weeks. The main goal was a change in baseline at the 48 week mark on the 16-point Scale for the Assessment and Rating of Ataxia, or SARA, which measures the loss of coordination and level of impairment in patients with the disease. Spinocerebeller ataxia is an inherited neurological disorder that progressively worsens movement.

The mean SARA score of participants at the start of the trial was 4.9, and after treatment, the patients reached 5.1 and 5.2 for the treatment and placebo arms, respectively. The study therefore failed to reach statistical significance. 

Biohaven referred to the disease progression as “less than expected” and highlighted specific genotype cohorts where the therapy had a larger benefit. The company added that the drug had a favorable safety and tolerability profile. 

Coric said the results "highlight some of the challenges of studying rare diseases such as SCA." 

Biohaven sold off its commercial-stage migraine med Nurtec ODT to Pfizer in addition to the clinical-stage, faster-acting nasal spray migraine treatment zavegepant in early May.

In a bit of good news amid the clinical trial flop, an application for zavegepant was accepted for review Monday by the FDA. However, that therapy will be under Pfizer's purview once the deal closes. The FDA decision date will likely be March 2023. 

Mizuho Securities analysts said the trial miss will have limited impact on Biohaven and should not affect the Pfizer deal in any way. There are no treatment options for this disease, so if Biohaven is able to find positive results for the subgroup as noted, troriluzole could still find a niche market. Mizuho, which had low expectations for the trial anyway, removed all potential sales of the therapy from its Biohaven models. 

In an interview at the beginning of May, Coric seemed upbeat about the remaining pipeline after the Pfizer deal. 

“There's a lot of value that's untapped yet in that and so depending on those study outcomes, either the value is going to go up, or we can also go raise money if we need to,” he said. 

When asked earlier in the month about how the company planned to replicate success, Coric threw his weight behind the company’s R&D team, which by and large is sticking around after the Pfizer buy. He said neuroscience was “not an area you can dabble in and go in and out of” and that his R&D team had the experience to produce another hit. 

Evidently, the company will need to look elsewhere for that value in the near term. Next up is the phase 3 ALS med verdiperstat, which is slated to readout in the coming months. The company is also about to hit the clinic with the lead asset acquired from Channel Biosciences back in February, BHV-7000. Coric described that therapy as “the next Nurtec potential.” Mizuho noted that the company's executives are "particularly excited" about that therapy, which is under development for focal epilepsy.  

Mizuho places much higher potential value on verdiperstat in its Biohaven models, as well as the spinal muscular atrophy med taldefgrobep alfa, which was licensed from Bristol Myers Squibb in February.