Astellas Pharma Inc. (TSE: 4503, President and CEO: Kenji Yasukawa, Ph.D., "Astellas") and Seagen Inc. (Nasdaq:SGEN) today announced the U.S. Food and Drug Administration (FDA) granted Padcev (enfortumab vedotin-ejfv) regular approval in the U.S., in addition to approving a new indication for adult patients with locally advanced or metastatic urothelial cancer who are ineligible for cisplatin-containing chemotherapy and have previously received one or more prior lines of therapy. Cisplatin-ineligible patients typically have limited treatment options and a poor prognosis.

In 2019, the FDA granted accelerated approval for Padcev for the treatment of adult patients with locally advanced or metastatic urothelial cancer who have previously received a PD-1/L1 inhibitor and a platinum-containing chemotherapy before (neoadjuvant) or after (adjuvant) surgery, or in a locally advanced or metastatic urothelial cancer setting. The conversion from accelerated approval to regular approval and the label expansion were based on two supplemental Biologics License Applications (sBLAs) reviewed under the Real-Time Oncology Review (RTOR) pilot program.

"The FDA's decision to convert accelerated approval to regular approval was based on data from the Phase 3 EV-301 trial, which had a primary endpoint of overall survival for patients treated with Padcev versus chemotherapy," said Andrew Krivoshik, M.D., Ph.D., Senior Vice President and Oncology Therapeutic Area Head, Astellas. "With Padcev, for the first time, physicians can treat advanced urothelial cancer following treatment with a platinum-containing therapy and immunotherapy using an FDA-approved therapy that has demonstrated an overall survival benefit compared with chemotherapy."

The EV-301 trial compared Padcev to chemotherapy in adult patients (n=608) 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 (n=301) in the trial lived a median of 3.9 months longer than those who received chemotherapy (n=307). Median overall survival was 12.9 vs. 9.0 months, respectively [Hazard Ratio=0.70 (95% Confidence Interval [CI]: 0.56, 0.89), p=0.001]. The most common all-grade adverse reactions (≥20%) included rash, fatigue, peripheral neuropathy, alopecia, decreased appetite, diarrhea, pruritus, nausea, constipation, dysgeusia, musculoskeletal pain, dry eye, pyrexia, abdominal pain and anemia.  

"Padcev is the first and only FDA-approved therapy for patients with locally advanced or metastatic urothelial cancer who have received immunotherapy and cannot receive cisplatin," said Roger Dansey, M.D., Chief Medical Officer, Seagen. "Because of the FDA's Real-Time Oncology Review, we're able to make Padcev available as early as possible to these patients, who have limited treatment options due to their age or comorbid conditions."

Cohort 2 of the EV-201 trial evaluated Padcev in patients (n=89) with locally advanced or metastatic urothelial cancer who had been previously treated with a PD-1/L1 inhibitor, had not received a platinum-containing chemotherapy in this setting, and were ineligible for cisplatin. After a median follow-up of 16 months, 51 percent of patients who received Padcev had an objective response [95% CI: 39.8, 61.3] per blinded independent central review, with a median duration of response of 13.8 months [95% CI: 6.4, not reached]. The most common all-grade adverse reactions (≥20%) included rash, peripheral neuropathy, alopecia, fatigue, decreased appetite, anemia, diarrhea, pruritus, weight decreased, nausea, dry eye and dysgeusia.  

"Almost half of advanced bladder cancer patients cannot receive cisplatin-based chemotherapy. Many of these patients will receive first-line immunotherapy. If their cancer does not respond -- or if it progresses after prior response to immunotherapy -- there is an urgent need for more treatment options as there is currently no standard of care," said Evan Y. Yu, M.D., Division of Oncology, Department of Medicine, University of Washington School of Medicine and a lead investigator for the EV-201 trial, in which all patients were previously treated with immunotherapy. "A new regulatory approval for enfortumab vedotin is an important clinical advance and can help serve this unmet need."

Globally, approximately 573,000 new cases of bladder cancer and more than 212,000 deaths are reported annually.1 Padcev is the subject of a robust development program aimed at addressing unmet needs across the continuum of urothelial cancer and in other solid tumors.

The FDA's RTOR program aims to explore a more efficient review process to ensure that safe and effective treatments are available to patients as early as possible. The agency's review was also conducted as part of Project Orbis, an initiative of the FDA Oncology Center of Excellence that provides a framework for concurrent submission and review of oncology drugs among participating international health authorities. Through Project Orbis, health authorities in Australia and Canada are continuing to review data from EV-301 and EV-201 for initial registrations.

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 608 patients with locally advanced or metastatic urothelial cancer who were previously treated with a PD-1/L1 inhibitor and platinum-based therapies.2 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. Results were published in the New England Journal of Medicine. 

About the EV-201 Trial

The EV-201 trial (NCT03219333) is a single-arm, multi-cohort, multicenter, pivotal phase 2 clinical trial of enfortumab vedotin for patients with locally advanced or metastatic urothelial cancer who have been previously treated with a PD-1 or PD-L1 inhibitor, including those who have also been treated with a platinum-containing chemotherapy (Cohort 1) and those who have not received a platinum-containing chemotherapy in this setting and who are ineligible for cisplatin (Cohort 2). The trial enrolled 125 patients in Cohort 1 and 89 patients in Cohort 2 at multiple centers internationally.3 The primary endpoint is confirmed objective response rate per blinded independent central review. Secondary endpoints include assessments of duration of response, disease control rate, progression-free survival, overall survival, safety and tolerability. Results of Cohort 2 were published in the Lancet Oncology.

About Padcev (enfortumab vedotin-ejfv)

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.4,5 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).5Padcev is co-developed by Astellas and Seagen.