Sesen Bio Announces Successful Type C Meeting with FDA for Vicinium

Sesen Bio (Nasdaq: SESN), a late-stage clinical company developing targeted fusion protein therapeutics for the treatment of patients with cancer, today reported alignment with the FDA on the design of its post-marketing confirmatory trial for Vicinium.

Sesen Bio reached agreement with the FDA that the post-marketing confirmatory trial for Vicinium will enroll BCG-refractory patients who have received less-than-adequate BCG^*, which is especially important in light of the ongoing BCG shortage. This represents a broader patient population than the originally proposed BCG-intolerant population. It is anticipated that, if Vicinium is approved by the FDA, the initial indication will be for BCG-unresponsive patients who have received adequate BCG. However, assuming the post-marketing confirmatory trial is successful, it is expected that labeling will be expanded to include this additional population of patients who have received less-than-adequate BCG.

“This was our third face-to-face meeting with the FDA in the past 6 months, and we continue to have very positive and constructive interactions, which help us advance Vicinium toward regulatory review and approval,” said Dr. Thomas Cannell, president and chief executive officer of Sesen Bio. “Our long-term relationship with the Agency has allowed us to shape our clinical program in alignment with FDA guidance. It has also helped to ensure that we are able to address the broadest possible segment of appropriate patients, and is expected to provide payers with the superiority data that will help to ensure product reimbursement. We look forward to our next FDA meeting in December.”

The trial is expected to be powered to demonstrate the superior efficacy of Vicinium compared to currently utilized therapies for the primary endpoints, which are expected to include the complete response (CR) rate and duration of response in CIS patients. Secondary endpoints are expected to include a number of quality of life, survival and safety endpoints, with the objective of demonstrating the superiority of Vicinium relative to currently utilized therapies. In addition, after a discussion of favorable Phase 3 post-hoc analyses with the FDA, the trial is expected to be designed to detect a delayed CR in patients who were non-CRs at the initial 3-month assessment.