SK Biopharmaceuticals will maintain its existing development and commercialization plans for its epilepsy drug candidate, Opacalim (BHV-7000), despite the U.S. Food and Drug Administration (FDA) placing a partial clinical hold on its U.S. clinical trials. The company was aware of this non-clinical finding before signing a licensing agreement with Biohaven last month. After internal reviews and external expert consultations, SK Biopharmaceuticals concluded that the likelihood of the same toxicity appearing in humans is low.
On Friday, SK Biopharmaceuticals held an online briefing to address the licensing agreement with Biohaven, signed on August 26, and the implications of the FDA’s partial clinical hold. Yoo Chang-ho, head of the Strategy Division and Business Development Department, who spearheaded the licensing negotiations, led the briefing.
Previously, on Thursday, SK Biopharmaceuticals disclosed that the FDA had issued a partial clinical hold on Opacalim’s U.S. clinical trials. The FDA requested additional data related to specific metabolites produced during Opacalim’s metabolism, observed in non-clinical studies on rodents. This measure aims to determine whether the observed phenomenon is rodent-specific or could potentially occur in humans.
SK Biopharmaceuticals emphasized that it’s inappropriate to view this issue as a new problem discovered post-contract signing. The company identified the non-clinical finding during months of due diligence before the agreement, reviewing relevant safety data with both internal researchers and external experts.
Yoo stated that they were fully aware of this issue before signing the contract. He added that based on their assessments and external expert advice, the company believes the unique metabolic process observed in rodents is unlikely to pose the same problem in humans.
He continued that it stands by the initial assessment and believe that this issue will have limited impact on Opacalim’s clinical and commercialization strategy.
This action differs from a full clinical hold, which would halt all clinical trials. Over 600 patients currently enrolled will continue their treatments as scheduled, while new patient enrollment is temporarily paused.
Notably, the Phase 3 clinical trial RISE3 completed patient recruitment in June, minimizing the impact of this action. The company plans to maintain its timeline for announcing topline results in the second half of this year.
While the Phase 2 clinical trial RISE2 has temporarily halted new patient enrollment, existing participants will continue their involvement. The company believes that if additional non-clinical data alleviates the FDA’s concerns, they can resume enrolling new patients without significantly affecting the overall development timeline.
Submission of Additional Data and Contract Closing
SK Biopharmaceuticals also emphasized that no safety signals related to the non-clinical findings have been confirmed in the clinical trials. Over 1,200 patients have participated in the trials to date, with no new adverse events or safety signals identified in relation to the findings observed in the rodent studies. The company stressed the need to differentiate between Opacalim’s clinical safety and tolerability assessments and the rodent-specific findings from non-clinical studies.
SK Biopharmaceuticals plans for Biohaven to submit additional non-clinical data to the FDA to resolve the partial clinical hold.
The company anticipates data submission between late September and early October, with the possibility of the FDA lifting the hold in October or November.
Yoo expressed optimism, stating that it expects Biohaven to submit the data to the FDA between late September and early October, with hopes of resolving the issues between October and November. He added that they will proceed with contract closing once the issues are resolved.
The licensing agreement remains at the contract signing stage, meaning the 400 million USD upfront payment SK Biopharmaceuticals is set to make to Biohaven has not yet been disbursed. Both parties are coordinating to finalize the transaction after addressing the FDA’s request for additional data.
On August 26, SK Biopharmaceuticals signed a global licensing agreement with Biohaven for new drug candidates, including Opacalim and Kv7 activators. The agreement, which includes the 400 million USD upfront payment, could total up to 795 million USD when accounting for milestone payments tied to development, approval, and commercialization.
Despite the FDA’s partial clinical hold, SK Biopharmaceuticals maintains that its assessment of Opacalim’s value as a new drug remains unchanged. The company plans to continue its scheduled clinical development and commercialization preparations, provided that the additional non-clinical data resolves the FDA’s concerns.