The U.S. Food and Drug Administration (FDA) has placed a partial clinical hold on the U.S. phase 2/3 trials of SK Biopharmaceuticals(326030)'s epilepsy drug candidate "opacalimide (BHV-7000)."
SK Biopharmaceuticals said on the 10th that a partial clinical hold was imposed on opacalimide's phase 2/3 trials, "RISE2" and "RISE3."
The action was notified by the FDA to Biohaven, opacalimide's partner.
Under the partial clinical hold, patients currently receiving the drug may continue dosing, but new patient enrollment is temporarily suspended. RISE3 has already completed enrollment, and SK Biopharmaceuticals said it is maintaining the schedule to announce topline (key endpoint) results in the second half of this year.
According to the company, the action follows the FDA's request for additional data related to toxicological findings observed in a nonclinical toxicity study in which a specific metabolite was administered to rodents. The FDA requested additional nonclinical evidence to determine whether the toxicity findings are a species-specific phenomenon limited to rodents.
SK Biopharmaceuticals said it reviewed the findings during due diligence before signing the license-in agreement with Biohaven. Based on the data secured at the time and external expert reviews, the company said it concluded the toxicity findings are species-specific to rodents and that the likelihood of the same issue occurring in humans is limited.
To date, clinical trials of opacalimide have been conducted in more than 1,200 participants. SK Biopharmaceuticals said no adverse events directly linked to the nonclinical toxicity findings have been identified in the clinical data secured so far.
Biohaven plans to work with the FDA to submit additional nonclinical evaluation data on the metabolite and seek to lift the partial clinical hold. SK Biopharmaceuticals is also discussing the FDA's requests and the requirements needed for lifting the hold with Biohaven.
The opacalimide license-in agreement between SK Biopharmaceuticals and Biohaven is still at a stage before transaction closing (Deal Closing).