-Enrollment of EV-201 Pivotal Trial Cohort Designed to Support Potential Expedited Registration Pathway in the U.S. Completed-

-First Patient Dosed in Phase 3 Global Confirmatory Trial-

BOTHELL, Wash., and TOKYO, July 9, 2018Seattle Genetics, Inc. (Nasdaq:SGEN) and Astellas Pharma Inc. (TSE: 4503, President and CEO: Kenji Yasukawa, Ph.D., “Astellas”) today announced completion of enrollment for the enfortumab vedotin EV-201 pivotal phase 2 clinical trial cohort of patients with locally advanced or metastatic urothelial cancer who have been previously treated with both platinum chemotherapy and a checkpoint inhibitor (PD-L1 or PD-1). Enfortumab vedotin is an investigational antibody-drug conjugate (ADC) that targets Nectin-4. 

The companies expect to report topline efficacy and safety results from this first cohort of the EV-201 trial, which is intended to support potential registration under the U.S. Food and Drug Administration’s (FDA) accelerated approval pathway, in the first half of 2019.

The companies also today announced dosing of the first patient in EV-301, a global, randomized phase 3 clinical trial evaluating enfortumab vedotin in patients with previously treated locally advanced or metastatic urothelial cancer. The EV-301 trial is intended to support a broader global registration strategy and to serve as the confirmatory randomized trial in the U.S. for EV-201. Enfortumab vedotin has been granted Breakthrough Therapy Designation by the FDA for patients with locally advanced or metastatic urothelial cancer who were previously treated with checkpoint inhibitors. 

“With enfortumab vedotin, we have the opportunity to address some of the unmet need in advanced urothelial cancer,” said Roger Dansey, M.D., Chief Medical Officer at Seattle Genetics. “With our partners Astellas, we are pleased to advance the enfortumab vedotin clinical trial program with the vision of bringing a new treatment option to patients with advanced urothelial cancer worldwide.”
 
“Despite recent treatment advances, the unfortunate reality is that many patients with metastatic urothelial cancer currently find that their disease will progress after anti-PD-1 or PD-L1 therapy, highlighting the need to identify additional therapeutic options,” said Steven Benner, M.D., Senior Vice President and Global Therapeutic Area Head, Oncology Development, Astellas. “Following encouraging results from our ongoing phase 1 study, we and our partners at Seattle Genetics decided to proceed with these registrational trials. We look forward to future clinical development milestones for enfortumab vedotin.” 

In addition to EV-201 and EV-301, enfortumab vedotin is also under evaluation in a phase 1 clinical trial (EV-103) in combination with pembrolizumab (Keytruda®) in cisplatin-ineligible first-line patients with locally advanced or metastatic urothelial cancer.