Pivotal Trial of Enfortumab Vedotin Shows Positive Topline Results in Locally Advanced or Metastatic Urothelial Cancer

The first cohort of patients in a pivotal phase II single-arm clinical trial, known as EV-201, shows positive topline results. EV-201 is an ongoing single-arm clinical trial.[1]

The cohort is evaluating enfortumab vedotin for the treatment of patients with locally advanced or metastatic urothelial cancer who have received previous treatment with both platinum-containing chemotherapy and a PD-1 or PD-L1 inhibitor (cohort 1), and those who have not received a platinum-containing chemotherapy and who are ineligible for cisplatin (cohort 2).

Urothelial cancer is the most common type of bladder cancer (90 percent of cases).[2] In 2018, more than 82,000 people were diagnosed with bladder cancer in the United States.[3] Globally, approximately 549,000 people were diagnosed with bladder cancer last year, and there were approximately 200,000 deaths worldwide.[4] Approximately 80 percent of people do not respond to PD-1 or PD-L1 inhibitors after a platinum-containing therapy has failed as an initial treatment for advanced disease.[5] There are currently no approved therapies for metastatic urothelial cancer once it has progressed after chemotherapy and a PD-1 or PD-L1 inhibitor.[6]

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Objective Response Rate
The results of the EV-201 trial showed a 44% objective response rate (ORR) per blinded independent central review. The duration of response was consistent with that recently reported in the previous phase I study (EV-101). The most common treatment-related adverse events included fatigue, alopecia, decreased appetite, rash and peripheral neuropathy. The data will be presented at an upcoming medical meeting.

The EV-201 phase II trial continues to enroll patients in cohort 2. In cohort 1, 128 patients were enrolled at multiple centers internationally.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.

Investigational ADC
Enfortumab vedotin is an investigational antibody-drug conjugate or ADC that targets Nectin-4, a cell adhesion molecule considered a therapeutic target that is highly expressed in multiple solid tumors including urothelial cancers. The drug includes an anti-Nectin-4 monoclonal antibody attached to a microtubule-disrupting agent (MMAE) using Seattle Genetics’ proprietary linker technology.

Based on preliminary results from a phase 1 trial (EV-101), enfortumab vedotin was granted Breakthrough Therapy designation by the U.S. Food and Drug Administration (FDA) for patients with locally advanced or metastatic urothelial cancer whose disease has progressed during or following treatment with a PD-1 or PD-L1 inhibitor.

Seattle Genetics and Astellas Pharma, the companies jointly developing the drug under a collaboration agreement that was entered into in 2007 and expanded in 2009, plan to submit a Biologics License Application (BLA) to the FDA later this year based on the results from the EV-201 trial (cohort 1).

A global, randomized phase III clinical trial (EV-301) is ongoing and intended to support global registration as well as to serve as the confirmatory randomized trial for enfortumab vedotin for patients with locally advanced or metastatic urothelial cancer who have been previously treated with a platinum-containing chemotherapy and a PD-1 or PD-L1 inhibitor.

“Despite recent approvals of multiple checkpoint inhibitors for previously treated locally advanced or metastatic urothelial cancer, there remains a high unmet need for effective treatments upon progression after initial chemotherapy and immunotherapy,” said Roger Dansey, M.D., Chief Medical Officer at Seattle Genetics.

“These results for enfortumab vedotin indicate it may be able to help patients whose urothelial cancer progresses following treatment with standard chemotherapy and a PD-1 or PD-L1 inhibitor,” Dansey added

“After progression on platinum-containing chemotherapy and a PD-1 or PD-L1 inhibitor, patients with locally advanced or metastatic urothelial cancer are left with no approved standard of care treatment options,” explained Steven Benner, M.D., Senior Vice President and Global Therapeutic Area Head, Oncology Development at Astellas.

“These data are very encouraging, and we look forward to discussing the data with relevant health authorities,” Banner concluded.

In addition to the ongoing confirmatory phase III study intended to also support global registration, development of enfortumab vedotin is underway in earlier lines of treatment for locally advanced or metastatic urothelial cancer, including in newly diagnosed patients in combination with pembrolizumab and/or platinum chemotherapy.

References
[1] A Study of Enfortumab Vedotin for Patients With Locally Advanced or Metastatic Urothelial Bladder Cancer (EV-201) | NCT03219333
[2] American Society of Clinical Oncology. Bladder Cancer: Introduction (10-2017).
[3] The Global Cancer Observatory: United States Overview
[4] Bray F, Ferlay J, Soerjomataram I, Siegel RL, Torre LA, Jemal A. Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 2018;68(6):394-424.
[5] Alhalabi O, Shah AY, Lemke EA, Gao J (2019). Immune checkpoint inhibitors in urothelial cancer. Oncology (Williston Park) 33(1): 1108.
[6] National Comprehensive Cancer Network. Bladder Cancer (Version 1.2019). http://www.nccn.org/professionals/physician_gls/pdf/bladder.pdf.

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