FDA Grants Priority Review to BLA for Vicineum for Treatment of High-Risk, BCG-Unresponsive NMIBC

The biologics license application is for the locally administered fusion protein Vicineum for the treatment of high-risk, bacillus Calmette-Guérin (BCG)–unresponsive non-muscle invasive bladder cancer.

The FDA has accepted and granted priority review to a biologics license application (BLA) for the locally administered fusion protein Vicineum for the treatment of high-risk, bacillus Calmette-Guérin (BCG)-unresponsive non-muscle invasive bladder cancer (NMIBC), according to the agent’s developer, Sesen Bio.1

Of note, the FDA indicated it is not currently planning to hold an advisory committee meeting to discuss the BLA. A prescription drug user fee act (PDUFA) target action date of August 18, 2021 has been assigned.

“We have been meeting with the FDA regularly for the past 2 years on the application for Vicineum,” Thomas Cannell, DVM, president and chief executive officer of Sesen Bio, said in a press release. “We understand the FDA’s position and guidance very clearly and have found the review process to be collaborative and engaging. With these critical FDA decisions, we have reached an inflection point for the company.”

Data from the phase 3 VISTA trial (NCT02449239) showed that patients with BCG-unresponsive NMIBC and carcinoma in situ had a complete response rate of 40% (95% CI, 30%-51%) at 3 months and 28% (95% CI, 19%-39%) at 6 months. Across all Vicineum-treated patients (n = 133), about 75% of patients were estimated to remain free of cystectomy at 2.5 years.2

Over the next 1 to 2 months, Sesen Bio indicated plans to submit a marketing authorization application (MAA) to the European Medicines Agency for Vicineum for the treatment of high-risk, BCG-unresponsive NMIBC. In addition, the company intends to receive an update from its partner, Qilu Pharmaceutical, regarding the possible approval of an investigational new drug (IND) application for Vicineum in China by the Center for Drug Evaluation.

Vicineum is comprised of a recombinant fusion protein that targets epithelial cell adhesion molecule (EpCAM) antigens on the surface of tumor cells to deliver a potent protein payload, Pseudomonas Exotoxin A. In prior research, EpCAM has been shown to be overexpressed in NMIBC cells with minimal to no EpCAM expression observed on normal bladder cells.

Currently, Sesen Bio is in the follow-up stage for the VISTA registration trial in the United States for the treatment of high-risk NMIBC in patients who have previously received a minimum of 2 courses of BCG and whose disease is now BCG-unresponsive. The activity of Vicineum in high-risk, BCG-unresponsive NMIBC is also being studied in combination with the immune checkpoint inhibitor durvalumab (Imfinzi) in a phase 1 trial (NCT03258593).


1. Sesen Bio announces FDA acceptance and priority review of its biologics license application for Vicineum. News release. Business Wire. Published February 16, 2021. Accessed February 17, 2021. https://www.businesswire.com/news/home/20210216005637/en/Sesen-Bio-Announces-FDA-Acceptance-and-Priority-Review-of-its-Biologics-License-Application-for-Vicineum%E2%84%A2

2. Sesen Bio reports positive, preliminary data update from phase 3 VISTA trial for high-risk non-muscle invasive bladder cancer. News release. Sensen Bio. August 8, 2019. Accessed February 17, 2021. http://bit.ly/3bj7Q2i