22 May 2019 - - US-based late-stage clinical company Sesen Bio (NASDAQ: SESN) has completed its Type C CMC meeting and has reached agreement with the US Food and Drug Administration on the Analytical Comparability Plan, and that, subject to final comparability data to be provided in the BLA submission, no additional clinical trials to establish comparability are deemed necessary at this time, the company said.

In its Phase 2 and 3 clinical trials, Sesen Bio manufactured Vicinium in its facility in Winnipeg, Manitoba. Based on the company's assessment of the global demand potential for Vicinium, Sesen Bio sought a commercial manufacturer with outstanding manufacturing quality, a proven track record with regulatory agencies, and the capacity to meet global demand forecasts.

In October 2018, Sesen Bio entered into an agreement for the manufacturing process and technology transfer of Vicinium production with Fujifilm Diosynth Biotechnologies USA., Inc. (Fujifilm).

In April 2019, the first in a series of full-scale, commercial GMP runs was successfully completed at Fujifilm. The final bulk drug substance produced in this first run met all release specifications.

On June 6, 2019, Sesen Bio will meet with the FDA for its second scheduled meeting, a Type B Pre-BLA meeting, to discuss the registration strategy for Vicinium.

Due to the wide-range of topics to be discussed at the Pre-BLA meeting, the company plans to provide an update on the outcome of that meeting upon receipt of the final meeting minutes, which is typically within 30 days.

Vicinium, a locally-administered fusion protein, is Sesen Bio's lead product candidate being developed for the treatment of high-risk non-muscle invasive bladder cancer (NMIBC).

Vicinium 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. Vicinium is constructed with a stable, genetically engineered peptide tether to ensure the payload remains attached until it is internalized by the cancer cell, which is believed to decrease the risk of toxicity to healthy tissues, thereby improving its safety.

In prior clinical trials conducted by Sesen Bio, EpCAM has been shown to be overexpressed in NMIBC cells with minimal to no EpCAM expression observed on normal bladder cells.

Sesen Bio is currently conducting the Phase 3 VISTA trial, designed to support the registration of Vicinium for the treatment of high-risk NMIBC in patients who have previously received a minimum of two courses of bacillus Calmette-Guérin and whose disease is now BCG-unresponsive.

Additionally, Sesen Bio believes that Vicinium's cancer cell-killing properties promote an anti-tumor immune response that may potentially combine well with immuno-oncology drugs, such as checkpoint inhibitors.

The activity of Vicinium in BCG-unresponsive NMIBC is also being explored at the US National Cancer Institute in combination with AstraZeneca's immune checkpoint inhibitor durvalumab.

Sesen Bio, Inc. is a late-stage clinical company advancing targeted fusion protein therapeutics for the treatment of patients with cancer.

The company's lead programme, Vicinium, also known as VB4-845, is currently in a Phase 3 registration trial, the VISTA trial, for the treatment of high-risk, BCG-unresponsive non-muscle invasive bladder cancer (NMIBC).

Vicinium is a locally-administered targeted fusion protein composed of an anti-EPCAM antibody fragment tethered to a truncated form of Pseudomonas Exotoxin A for the treatment of high-risk NMIBC.