Seattle Genetics’ (NASDAQ:SGEN) tisotumab vedotin needs to show longer responses in metastatic cervical cancer patients in a Phase II study than those previously seen in Phase I/II data in order to prove clinical significance and potentially support approval, experts said.
An analyst noted that early Phase I/II tisotumab efficacy results in cervical cancer patients from innovaTV 201 (NCT02001623) was strong enough to support further development since the objective response rate (ORR) with standard therapies is less than 20%. While experts agreed tisotumab’s ORR was better than available therapies, they emphasized the need for it to cause more durable responses in the ongoing Phase II innovaTV 204 than those seen in innovaTV 201. Even though duration of response (DOR) is not a primary endpoint, one expert said it will likely be considered during approval, given the low tisotumab ORR.
The first analyst noted ocular toxicities seen with tisotumab are a key issue, but experts said they will likely be manageable with eye drops and other mitigating measures.