Sesen Bio to present its three-month Phase 3 VISTA Trial data at Global Congress

Sesen Bio, Inc., a late-stage clinical company developing fusion protein therapies for the treatment of cancer, today announced that the company will present its three-month Phase 3 VISTA Trial data during a poster session at the Global Congress on Bladder Cancer 2018. The congress is being held Sept. 20-21, 2018 in Madrid. The ongoing VISTA registration trial is evaluating Vicinium™, Sesen Bio's lead product candidate, for the treatment of people with high-grade non-muscle invasive bladder cancer (NMIBC) who have been previously treated with bacillus Calmette-Guérin (BCG).

The data, which were presented during a plenary session at the American Urological Association Annual Meeting in May 2018, include a biomarker update showing that nearly all screened patient samples expressed EpCAM, the molecular target of Vicinium.

"We are delighted to present the three-month VISTA Trial data at the Global Congress on Bladder Cancer and further showcase the promise of Vicinium in treating people with NMIBC," said Dr. Thomas Cannell, president and chief executive officer of Sesen Bio. "Today, patients who are unresponsive or become refractory to BCG therapy have virtually one option: complete removal of their bladder. This is a long, challenging and life-altering procedure with a high rate of mortality that nearly half of people who face it choose not to undergo. It is critically important that such people are provided an effective and tolerable option that spares them from having to make such a difficult decision and saves their bladder. We believe that Vicinium holds significant potential as a targeted treatment that could renew the lives of these underserved patients."

As announced in May, the three-month data are from 111 patients in the VISTA Trial with high-grade NMIBC that is either carcinoma in situ (CIS), which is cancer found on the inner lining of the bladder that has not spread into muscle or other tissue, with or without papillary disease, or from patients with papillary disease without CIS, which is cancer that has grown from the bladder lining out into the bladder, but has not spread into muscle or other tissue. In an analysis assessing pooled CIS patients (n=77), based on final U.S. Food and Drug Administration guidance on treatment of BCG-unresponsive CIS NMIBC patients (defined as patients with recurrent CIS within 12 months of adequate BCG therapy), Vicinium treatment resulted in a complete response rate of 42 percent at three months. In patients with papillary disease without CIS, treatment with Vicinium demonstrated a 68 percent recurrence-free rate at three months.

In addition, Vicinium has been well-tolerated in the VISTA Trial. Of the treatment-related adverse events in the three-month analysis, four percent were Grade 3 or 4, with no Grade 5 treatment-related adverse events. Four treatment-related serious adverse events were reported, including acute kidney injury or renal failure and cholestatic hepatitis.