Colleen Hanley's questions to Mersana Therapeutics (MRSN) leadership • Q1 2025
Question
Colleen Hanley requested more color on the rationale for pursuing a randomized Phase III trial, which management suggested wouldn't take much longer than a single-arm study. She also asked about the work needed to confirm the B7-H4 expression cutoff for patient selection.
Answer
An executive, likely CEO Dr. Martin Huber, detailed the advantages of a randomized trial, including broader global regulatory acceptance, avoiding a separate confirmatory trial, and generating robust PFS and OS data quickly. Regarding the B7-H4 biomarker, he explained that work to refine the assay is ongoing in the expansion cohorts. CEO Dr. Martin Huber added that while the exact cutoff score might be tweaked, they anticipate the positive patient population will remain in the 40-50% range, identifying a consistent group of patients.