Surprise FDA rejection halts Sesen Bio's launch in its tracks, putting newly hired sales team in limbo

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Sesen Bio's CEO noted an "unprecedented level of scrutiny at the FDA" after the company's bladder cancer drug was turned down. (Getty Images)

Last week, Sesen Bio was finalizing label wording with the FDA on its bladder cancer hopeful Vicineum. This week, the CEO is explaining to investors how it will continue going forward after an FDA rejection.

The unexpected FDA turn on Vicineum caught Sesen and its followers by surprise—but it’s far from alone lately. Now, the company has to decide how it can regroup and make its way back to the FDA as well as how to handle the dozens of staffers it recently recruited to prepare for its launch.

Sesen CEO Thomas Cannell, M.D., said in a call Monday that he and his team saw a recent analysis that found 15% of FDA decisions from January to June this year resulted in complete response letters like the one Sesen got. That percentage boomed to 50% from June through today.

For now, Sesen’s Vicineum commercial plan is stalled—putting its newly hired 34 sales reps and 25 internal support staff on hold. Sesen also recently brought in and began training a 14-person key opinion leader group to engage and educate physicians on Vicineum.

Sesen declined comment beyond the Monday conference call as it plots its next moves.

First up is a meeting with the FDA. Cannell and his team worked all weekend on a meeting request in response to the Friday letter, and the CEO expects that to come in the fourth quarter.

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If another trial is needed, as is expected, Cannell anticipates setting up and running a 12-month study means the company could resubmit its drug in 2023.

While Cannell praised the FDA oncology review team in a conference call Monday, he did weigh in on what may be happening at the agency when asked by an analyst.

“At the macro level, there is an unprecedented level of scrutiny at the FDA. Maybe the most scrutiny we’ve seen since the early 1960s,” he said.

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He pointed to the added stress of the pandemic and shift to vaccine work, followed more recently by “toxic media coverage” around the agency's approval of Biogen’s Alzheimer’s disease drug Aduhelm and an ensuing inspector general review, as contributions to the new atmosphere.

“When you’re under pressure, the risk-averse or the safer strategy will always be to punt the ball down the field and ask for more data,” Cannell said.

In the past two weeks alone, the FDA has spiked AstraZeneca and FibroGen’s first-in-class anemia candidate roxadustat and Ardelyx’s chronic kidney disease drug tenapanor.