- Durable Responses Observed in Second Cohort of Patients in Pivotal EV-201 Trial of PADCEV and in Initial First-Line Cohort of the EV-103 Trial Evaluating PADCEV in Combination with KEYTRUDA® (pembrolizumab) -

-  Data to be Presented in Virtual Scientific Program of the 2021 American Society of Clinical Oncology Annual Meeting -

TOKYO & BOTHELL, Wash. – May 19, 2021 – Astellas Pharma Inc. (TSE: 4503, President and CEO: Kenji Yasukawa, Ph.D., “Astellas”) and Seagen Inc. (Nasdaq:SGEN) today announced updated results from two clinical trials examining PADCEV® (enfortumab vedotin-ejfv) alone (EV-201 Cohort 2) and PADCEV in combination with Merck’s (known as MSD outside the United States and Canada) KEYTRUDA® (pembrolizumab) (EV-103 Cohort A) in patients with locally advanced or metastatic urothelial cancer who are not able to receive cisplatin chemotherapy.

“EV-201 Cohort 2 is the first study to report objective responses in patients with advanced urothelial cancer that progressed following immunotherapy and who have medical conditions that prevent them from receiving cisplatin chemotherapy,” said Andrew Krivoshik, M.D., Ph.D., Senior Vice President and Oncology Therapeutic Area Head, Astellas. “The analysis that will be presented at ASCO showed that after a median follow-up of 16 months, many patients continued to benefit from PADCEV – an important finding for these patients, who have very limited treatment options.”

“EV-103 is the first clinical trial to combine the antibody-drug conjugate PADCEV with Merck’s 
anti-PD-1 therapy KEYTRUDA in patients newly diagnosed with locally advanced or metastatic urothelial cancer,” said Roger Dansey, M.D., Chief Medical Officer, Seagen. “The updated data from EV-103 Cohort A, with two years of follow-up, build upon findings from the initial analysis, showing continued durability for this platinum-free combination.”

Enfortumab vedotin in cisplatin-ineligible patients with locally advanced or metastatic urothelial cancer who received prior PD-1/PD-L1 inhibitors: An updated analysis of EV-201 Cohort 2 (Abstract 4524)

Patients in Cohort 2 of EV-201 received prior treatment with an immunotherapy but had not received a platinum-containing chemotherapy in the locally advanced or metastatic setting and were ineligible for cisplatin chemotherapy.

With a median follow-up of 16 months, 51 percent of patients who received PADCEV had a confirmed objective response [95% Confidence Interval (CI): 39.8, 61.3] per blinded independent central review (the primary endpoint), with 22 percent of patients experiencing a complete response (CR). Median duration of response (DOR) was 13.8 months [95% CI: 6.4, not reached]. Patients lived a median of 6.7 months without cancer progression [progression-free survival (PFS) (95% CI: 5.0-8.3)] and had a median overall survival (OS) of 16.1 months (95% CI: 11.3, 24.1).

The most common all-grade treatment-related adverse events (TRAEs) were alopecia (51%), peripheral sensory neuropathy (49%) and fatigue (34%), and the most common Grade 3 or greater TRAEs were neutropenia (9%), maculopapular rash (8%) and fatigue (7%). Grade 3 or greater TRAEs of special interest included skin reactions (17%), peripheral neuropathy (8%) and hyperglycemia (6%). Four deaths were previously reported as treatment-related by investigators in patients age 75 years and older with multiple comorbidities.

The U.S. Food and Drug Administration (FDA) recently granted Priority Review to a supplemental application for PADCEV based on the primary analysis from EV-201 Cohort 2, which was published this month in The Lancet Oncology.

Study EV-103: Update on durability results and long-term outcome of enfortumab vedotin + pembrolizumab in first-line locally advanced or metastatic urothelial carcinoma (la/mUC) (Abstract 4528)

In the dose-escalation cohort and expansion Cohort A in EV-103, patients were treated with a combination of PADCEV and the anti-PD-1 therapy KEYTRUDA as a first-line treatment for locally advanced or metastatic disease. Participants were ineligible for cisplatin-based chemotherapy, had no prior systemic treatment for locally advanced or metastatic disease, and did not receive adjuvant/neoadjuvant platinum-based therapy within 12 months prior to enrollment.

The primary outcome measure in this analysis was safety. With a median follow-up of 24.9 months, the longer-term analysis demonstrated a safety profile generally consistent with previous findings, with no new safety signals observed. The most common TRAEs were peripheral sensory neuropathy (55.6%), fatigue (51.1%) and alopecia (48.9%), and the most common Grade 3 or greater TRAEs were increased lipase (17.8%), maculopapular rash (11.1%) and fatigue (11.1%). Grade 3 or greater TRAEs of interest included skin reactions (20%), hyperglycemia (8.9%) and peripheral neuropathy (4.4%). There was one death previously reported as possibly related to study treatment (multiple organ dysfunction syndrome).

As previously reported, results demonstrated an objective response rate of 73.3 percent (95% CI: 58.1, 85.4) per investigator assessment, with 15.6 percent of patients experiencing a CR. The median PFS was 12.3 months (95% CI: 8.0, not reached). With longer-term follow-up, the study showed a median DOR of 25.6 months (95% CI: 8.3, not reached) and median OS of 26.1 months (95% CI: 15.7, not reached).

The FDA granted Breakthrough Therapy designation last year for the PADCEV and KEYTRUDA combination for patients with unresectable locally advanced or metastatic urothelial cancer who are unable to receive cisplatin-based chemotherapy in the first-line setting.

 

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