Sesen Bio reports progress with regulators as it preps for new cancer trial, but issues remain

Days after announcing it was looking for an exit route to stay alive, Sesen Bio reported progress from a March meeting with regulators as it preps for a new phase 3 trial of its cancer drug. 

The FDA agreed to a majority of its proposals for a new phase 3 study of its med vicineum at a March 28 meeting, the company revealed in its first-quarter earnings report Monday. Sesen said it would request an additional meeting with regulators “in the coming weeks” and expects it to be held in mid-2022. 

In the meantime, the biotech reported that it was progressing through problems regarding chemistry, manufacturing and controls raised in the regulator’s complete response letter handed out last August when vicineum was rejected to treat a form of bladder cancer. But the fixes made won’t be addressed by the FDA until the company reapplies for approval, if that ultimately happens. 

The March 28 meeting was the third between regulators and Sesen after the drug was spiked down in August 2021. The biotech conveyed at the time that the rejection was unexpected—however, reporting from STAT News unearthed more than 2,000 violations of the company's study protocol. 

Sesen subsequently pulled its approval application in Europe and has been on the mend ever since, bullish that it would pursue a new phase 3 trial to right the wrongs of the first. That is, if another company doesn’t elect to buy it off Sesen beforehand. 

As part of its first-quarter earnings, Sesen reported having $170 million at the end of March, enough to fund its operations into the fourth quarter of 2024.