FDA Denies Vicineum Approval for Non-Muscle Invasive Bladder Cancer

Sesen Bio is a late-stage clinical company developing promising targeted fusion protein therapeutics for the treatment of cancer. But the company got bad news recently when it received a complete response letter — a form of rejection — from FDA for Vicineum (oportuzumab monatox-qqrs) for the treatment of patients with non-muscle invasive bladder cancer that hasn’t responded to a common treatment.

“We are deeply disappointed by this unexpected result, and it is an unfortunate day for patients suffering from BCG-unresponsive NMIBC.We remain dedicated to our mission to save and improve the lives of patients by bringing new treatment options to patients, and we intend to work closely with the FDA to understand next steps,” said Thomas Cannell, D.V.M., president, and chief executive officer of Sesen Bio.

BCG stands for bacillus Calmette-Guerin, a live weakened strain of the Mycobacterium bovis. Infusing BCG directly into the bladder is one treatment option for bladder cancer. It is often used after the cancer has come back. Why BCG works to combat cancer isn’t fully understood but it may coax the immune system into action in a way that mounts an immunological response to the cancer..

The FDA outlined specific recommendations for additional clinical/statistical data and analyses of Vicineum, in addition to chemistry, manufacturing, and controls issues regarding a recent preapproval inspection and product quality.

The company plans to request a Type A meeting with the FDA to discuss the future steps required before the BLA can be approved. Type A meetings with the FDA may include the following:

• Dispute resolution meetings
• Discuss clinical holds
• Review special protocol assessments
• Post-action meetings requested by the sponsor within 3 months after an FDA regulatory action other than an approval

Vicineum targets epithelial cell adhesion molecule antigens (EpCAM) on the surface of tumor cells, and this innovative technology is expected to decrease the risk of toxicity to health tissues to improve drug safety. Additionally, EpCAM has been shown to be overexpressed in non-muscle invasive bladder cancer.

The FDA accepted the Sesen Bio’s application for Vicineum in February 2021, and the application was granted priority review.

Non-muscle invasive bladder cancer is, as the name suggests, bladder cancer that occurs in the surface of the bladder cancer (the inside surface), not the muscle tissue of the organ.