Sesen slams brakes on phase 3 bladder cancer program to save cash as it looks for off-ramp

Sesen Bio is pumping the brakes on its phase 3 bladder cancer program. After weighing up what it will take to get Vicineum to market, the biotech has paused clinical development in the U.S. to preserve the cash that could be key to its exit.

The FDA dealt a big blow to Sesen last summer when it rejected a request for approval of Vicineum in non-muscle invasive bladder cancer (NMIBC). Initially, Sesen remained committed to the program, working with the FDA to agree on an additional phase 3 clinical trial even as it began looking for strategic alternatives. Now, the biotech’s willingness to pump its remaining funds into Vicineum has wavered.

Sesen decided to pause clinical development of Vicineum in the U.S. after reassessing the program in light of its talks with the FDA. The reassessment covered “the incremental development timeline and associated costs” of the additional phase 3 trial needed to win FDA approval and other factors. 

“We have also recently observed an evolution of the current treatment paradigm in NMIBC, with substantial uptake of intravesical chemotherapy (monotherapy and combination therapy) during the ongoing BCG shortage,” Sesen CEO Thomas Cannell said in a statement. “In assessing the impact of the regulatory and commercial landscape, we have made the decision to pause the clinical development of Vicineum.”

While Sesen is opting against plowing its own dollars into Vicineum, it continues to argue the candidate is a worthwhile investment for others and is planning to seek a partner for Vicineum and conserve cash while seeking strategic alternatives. Other struggling companies, such as Yumanity Therapeutics, have recently offloaded drugs to one buyer and their cash and Nasdaq listing to another. 

Sesen had $161.2 million in the bank at the end of June, down from $169.8 million three months earlier. With no outstanding debt, Sesen’s cash may prove to be among its more attractive assets in the current biotech market, as was the case when Tyme Technologies landed a deal with Syros Pharmaceuticals.

Shares in Sesen fell 22% to $0.69 in the opening hour of trading.