Charles Zhu's questions to Mersana Therapeutics (MRSN) leadership • Q2 2025
Question
Charles Zhu from LifeSci Capital, LLC asked if the TPS 70% cutoff for B7-H4 high expression is now settled and how the company will evaluate the clinical profile trade-off between the two dosing regimens (Dose A vs. Dose B) given the new mitigation strategies.
Answer
President and CEO Dr. Martin Huber responded that the upcoming expansion data will be used to finalize the B7-H4 cut point, though he anticipates the 'high' population will remain around 40-50% of patients. He explained that the key hypothesis is that Dose B, without treatment interruptions, will yield better efficacy. The upcoming data will be critical to determine if the efficacy gain justifies the higher dose; otherwise, Dose A would be the go-forward option.