Immunogen puts Sutro on alert

41 years since its inception and following a previous pivotal failure, Immunogen has its first FDA approval. Elahere, a folate receptor alpha (FRα)-targeting antibody-drug conjugate, yesterday secured an accelerated nod for FRα-positive platinum-resistant ovarian cancer. There are reasons to be cautious about its prospects, however. For one the product has, as expected, come with a black box warning for ocular toxicity, potentially limiting commercial uptake. And investors now face a nervous wait for results from the confirmatory Mirasol trial, due early next year. Wells Fargo analysts think that the FDA has seen preliminary data from that study. Immunogen’s stock opened up 9% this morning on hopes that Elahere could become standard of care. A question now is what this means for Sutro, which is also targeting accelerated approval for its similarly acting agent, STRO-002. That group hopes to treat more patients: 70% of the platinum-resistant ovarian cancer population versus the 40% or so FRα-high patients eligible for Elahere. Also, while STRO-002 has not been linked with eye toxicity, it has been associated with neutropenia. Sutro, whose chief medical officer quit last month, is set to unveil its pivotal trial design by year end.