– Findings from the EV-301 Trial Showed Significant Improvements in Overall Survival and Progression-Free Survival Compared to Chemotherapy –

– EV-301 Intended to Support Global Registrations, Convert Accelerated to Regular Approval in U.S. –

– Data Published in the New England Journal of Medicine, Presented at the 2021 ASCO Genitourinary Cancers Symposium –

BOTHELL, WA, USA & TOKYO, Japan I February 12, 2021 I Seagen Inc. (Nasdaq:SGEN) and Astellas Pharma Inc. (TSE: 4503, President and CEO: Kenji Yasukawa, Ph.D., “Astellas”) today announced primary results from the phase 3 EV-301 trial comparing PADCEV® (enfortumab vedotin-ejfv) to chemotherapy in adult patients with locally advanced or metastatic urothelial cancer who were previously treated with platinum-based chemotherapy and a PD-1/L1 inhibitor. At the time of pre-specified interim analysis, patients who received PADCEV in the trial lived a median of 3.9 months longer than those who received chemotherapy. Median overall survival was 12.9 vs. 9.0 months, respectively (HR=0.70 [95 percent Confidence Interval (CI): 0.56-0.89], p=0.001). For patients in the PADCEV arm of the trial, maculopapular rash, fatigue and decreased neutrophil count were the most frequent Grade 3 or greater treatment-related adverse events (TRAEs) occurring in more than 5 percent of patients.

Urothelial cancer is the most common type of bladder cancer and can also be found in the renal pelvis, ureter and urethra.1

The findings were published in the New England Journal of Medicine and presented during the virtual scientific program of the 2021 American Society of Clinical Oncology Genitourinary Cancers Symposium (ASCO GU) (Abstract 393).

“Improving survival is especially meaningful in patients who have had their cancer progress following chemotherapy or other treatment,” said Daniel P. Petrylak, M.D., Professor of Medicine and of Urology, Yale Cancer Center, and corresponding author of the published study.

“Enfortumab vedotin is the first medicine to reduce the risk of death compared to chemotherapy in patients with locally advanced or metastatic urothelial cancer who have received a platinum-containing chemotherapy and an immunotherapy,” said Professor Thomas Powles, M.D., Director, Barts Cancer Centre, Queen Mary University of London, who presented results at ASCO GU.

Patients who received PADCEV in the trial also showed improvement in the following secondary endpoints:

  • Median progression-free survival, which is the time without progression of cancer, was 5.6 months for PADCEV vs. 3.7 months for chemotherapy (HR=0.62 [95 percent CI: 0.51-0.75]; p<0.00001).
  • Overall response rate, the percentage of patients with either complete or partial response, was 40.6 percent vs. 17.9 percent of patients in the chemotherapy arm (p<0.001).
  • Disease control rate (DCR), which is the percentage of patients who have achieved complete response, partial response or had stable disease, was 71.9 percent for PADCEV and 53.4 percent for chemotherapy (p<0.001).

Other safety findings included:

  • Rates of serious TRAEs were comparable between treatment arms (23 percent of patients receiving PADCEV vs. 23 percent receiving chemotherapy).
  • Grade 3 or greater TRAEs were experienced by approximately 50 percent of patients in both study arms. Grade 3 or greater TRAEs occurring in more than 5 percent of patients receiving PADCEV were maculopapular rash (occurring in 7 percent of patients receiving PADCEV vs. 0 percent of patients receiving chemotherapy), fatigue (6 percent vs. 4.5 percent) and decreased neutrophil count (6 percent vs. 13 percent).

“Since its accelerated approval by the FDA in late 2019, physicians have adopted PADCEV into their practice, and these confirmatory results provide additional evidence of its benefit for people living with advanced bladder cancer,” said Roger Dansey, M.D., Chief Medical Officer, Seagen.

“Patients who received PADCEV lived longer than those who received chemotherapy – an important finding, especially in light of the high unmet need faced by people with advanced urothelial cancer,” said Andrew Krivoshik, M.D., Ph.D., Senior Vice President and Oncology Therapeutic Area Head, Astellas.

Results of EV-301 are expected to be submitted to the U.S. Food and Drug Administration by the end of March as the confirmatory trial following the drug’s accelerated approval in 2019. The results of EV-301 will also be included in submissions to global health authorities.

About Urothelial Cancer

Urothelial cancer is the most common type of bladder cancer (90 percent of cases) and can also be found in the renal pelvis (where urine collects inside the kidney), ureter (tube that connects the kidneys to the bladder) and urethra.1 Globally, approximately 549,000 new cases of bladder cancer and 200,000 deaths are reported annually.2

About the EV-301 Trial

The EV-301 trial (NCT03474107) is a global, multicenter, open-label, randomized phase 3 trial designed to evaluate enfortumab vedotin versus physician’s choice of chemotherapy (docetaxel, paclitaxel or vinflunine) in approximately 600 patients with locally advanced or metastatic urothelial cancer who were previously treated with a PD-1/L1 inhibitor and platinum-based therapies. The primary endpoint is overall survival and secondary endpoints include progression-free survival, overall response rate, duration of response and disease control rate, as well as assessment of safety/tolerability and quality-of-life parameters.

About PADCEV® (enfortumab vedotin-ejfv)

PADCEV was approved by the U.S. Food and Drug Administration (FDA) in December 2019 and is indicated for the treatment of adult patients with locally advanced or metastatic urothelial cancer who have previously received a programmed death receptor-1 (PD-1) or programmed death-ligand 1 (PD-L1) inhibitor and a platinum-containing chemotherapy before (neoadjuvant) or after (adjuvant) surgery or in a locally advanced or metastatic setting. PADCEV was approved under the FDA’s Accelerated Approval Program based on tumor response rate. Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trials.3

PADCEV is a first-in-class antibody-drug conjugate (ADC) that is directed against Nectin-4, a protein located on the surface of cells and highly expressed in bladder cancer.3,4 Nonclinical data suggest the anticancer activity of PADCEV is due to its binding to Nectin-4 expressing cells followed by the internalization and release of the anti-tumor agent monomethyl auristatin E (MMAE) into the cell, which result in the cell not reproducing (cell cycle arrest) and in programmed cell death (apoptosis).4 PADCEV is co-developed by Seagen and Astellas.

About Seagen

Seagen Inc. is a global biotechnology company that discovers, develops and commercializes transformative cancer medicines to make a meaningful difference in people’s lives. Seagen is headquartered in the Seattle, Washington area, and has locations in California, Canada, Switzerland and the European Union. For more information on our marketed products and robust pipeline, visit www.seagen.com and follow @SeagenGlobal on Twitter.

About Astellas

Astellas Pharma Inc. is a pharmaceutical company conducting business in more than 70 countries around the world. We are promoting the Focus Area Approach that is designed to identify opportunities for the continuous creation of new drugs to address diseases with high unmet medical needs by focusing on Biology and Modality. Furthermore, we are also looking beyond our foundational Rx focus to create Rx+® healthcare solutions that combine our expertise and knowledge with cutting-edge technology in different fields of external partners. Through these efforts, Astellas stands on the forefront of healthcare change to turn innovative science into value for patients. For more information, please visit our website at https://www.astellas.com/en.

About the Seagen and Astellas Collaboration

Seagen and Astellas are co-developing enfortumab vedotin under a collaboration that was entered into in 2007 and expanded in 2009.

References

1   American Society of Clinical Oncology. Bladder cancer: introduction (5-2019). https://www.cancer.net/cancer-types/bladder-cancer/introduction. Accessed January 27, 2021.
2   Cancer today: data visualization tools for exploring the global cancer burden in 2020. https://gco.iarc.fr/today/home. Accessed January 27, 2021.
3   PADCEV [package insert] Northbrook, IL: Astellas, Inc.
4   Challita-Eid P, Satpayev D, Yang P, et al. Enfortumab vedotin antibody-drug conjugate targeting nectin-4 is a highly potent therapeutic agent in multiple preclinical cancer models. Cancer Res 2016;76(10):3003-13.

SOURCE: SeaGen