Sesen meets with FDA over Vista in May and June

Company Announces Confirmed Meetings with the U.S. Food and Drug
Administration in May and June 2019 to Review Registration
Strategy for Vicinium^®

Management to Host a Business Update Call Today at 8:00 a.m. EDT

CAMBRIDGE, Mass.–(BUSINESS WIRE)–Sesen Bio (Nasdaq:SESN), a late-stage clinical company developing
targeted fusion protein therapeutics for the treatment of patients with
cancer, today reported operating results for the first quarter ended
March 31, 2019. The Company also reported updated, preliminary primary
and additional secondary endpoint data from the Company’s Phase 3 VISTA
trial further supporting the strong benefit-risk profile of Vicinium
for the potential treatment in patients with high-risk, bacillus
Calmette-Guérin (BCG) unresponsive, non-muscle invasive bladder
cancer (NMIBC). The updated preliminary Phase 3 clinical data, along
with the Phase 2 clinical trial data, will serve as the basis for
upcoming meetings with the U.S. Food and Drug Administration (FDA).

“We are very encouraged by the most recent analysis of our 12-month
Phase 3 VISTA trial data, which will be the basis for our meetings with
the FDA in May and June,” said Dr. Thomas Cannell, president and chief
executive officer of Sesen Bio. “We believe these preliminary data,
along with a closely matched Phase 2 data set, support a compelling
benefit-risk profile, and give us confidence in the regulatory
approvability and strong commercial viability of Vicinium. The huge
unmet need for patients with NMIBC is widely acknowledged and has been
exacerbated by the recurring global shortage of BCG. We will continue to
work closely with the FDA in our effort to expeditiously bring a product
to market that has the potential to save and improve the lives of
patients with NMIBC.”