Brian Abrahams's questions to Xenon Pharmaceuticals Inc (XENE) leadership • Q2 2025
Question
Brian Abrahams of RBC Capital Markets questioned if the final size of the EXTOL-two study might exceed the planned 360 subjects and asked about the company's latest assumptions for seizure reduction delta and dropout rates, given the historically high translatability between Phase II and Phase III epilepsy trials.
Answer
President and CEO Ian Mortimer clarified that the target remains approximately 360 subjects and the study is highly powered, making over-enrollment unnecessary. He emphasized that the primary goal for EXTOL-two is achieving statistical significance to support the NDA filing. Chief Medical Officer Christopher Kenney added that blinded metrics on patient characteristics and rollover rates appear consistent with the successful Phase IIb EXTOL study.