Mersana starts to lose its shine

More data are not always a good thing. Just ask Mersana, which sank 29% yesterday on the latest update on its lead antibody-drug conjugate, XMT-1536, in ovarian cancer.

The data look worse than those shared at last year’s Esmo meeting, which concerned an earlier cut from the same study. Specifically, yesterday’s update revealed a shrinking overall response rate, more adverse events including a treatment-related death, and unimpressive durability.