Enfortumab vedotin impresses in post-immunotherapy bladder cancer

The antibody-drug conjugate (ADC) enfortumab vedotin-ejfv (Padcev) induced a response in over half of patients with advanced urothelial cancer who previously received a PD-1/PD-L1 inhibitor but were ineligible for cisplatin, according to findings from the pivotal phase 2 EV-201 trial.¹

In the cohort of patients—who had also not had prior platinum-based chemotherapy—enfortumab vedotin achieved an objective response rate of 52% per the review of an independent panel.

Regarding safety, adverse events occurring in above 5% of patients included, rash, neutropenia, diarrhea, fatigue, anemia, increased lipase, hyperglycemia, and decreased appetite.

Arjun Balar, MD

“Advanced urothelial cancer in patients who have received immunotherapy and are ineligible for cisplatin is a particularly difficult disease to treat,” EV-201 study investigator Arjun Balar, MD, associate professor of medicine, director of the Genitourinary Medical Oncology Program, NYU Laura and Isaac Perlmutter Cancer Center, NYU Langone Health, stated in a press release.“Typically, these patients are frail, suffer from multiple comorbidities beyond their urothelial cancer and are not able to tolerate additional treatment beyond immunotherapy, leading many to discontinue therapy altogether.”

All patients in the single-arm, international EV-201 trial (NCT03219333) had locally advanced or metastatic urothelial cancer previously treated with a PD-1 or PD-L1 inhibitor. Patients were then stratified by prior chemotherapy: cohort 1 (128 patients) included patients previously treated with platinum-based chemotherapy and cohort 2 (91 patients) included patients without prior platinum-based chemotherapy who were also ineligible for cisplatin.

In the press release,1 Seagen and Astellas, the codevelopers of enfortumab vedotin, reported that beyond the findings announced today, additional data from cohort 2 will be shared at an upcoming medical meeting.

“This is the first trial to report objective responses in patients with advanced urothelial cancer who had previously received immunotherapy but were ineligible for cisplatin in this setting due to inadequate kidney function or other conditions,” Roger Dansey, MD, chief medical officer at Seagen, stated in the press release. “These promising new data from EV-201 may support a regulatory application to extend use of Padcev in US patients whose cancer has progressed after immunotherapy and who are ineligible for cisplatin.”

Cohort 1

Data from cohort 1 of EV-201 recently presented during the 2020 ESMO Congress showed overall survival (OS) rates of 50.4% at 12 months and 34.2% at 18 months with enfortumab vedotin in patients with locally advanced or metastatic urothelial cancer previously treated with platinum-based chemotherapy and immune checkpoint inhibitors.² At a median follow-up of 22.3 months, the median OS was 12.4 months.

Based on initial data from EV-201 reported prior to the ESMO Congress, the FDA granted enfortumab vedotin an accelerated approval in December 2019 for the treatment of patients with locally advanced or metastatic urothelial cancer previously treated with a PD-1/PD-L1 inhibitor and platinum-based chemotherapy in the neoadjuvant/adjuvant, locally advanced or metastatic setting.³

EV-301

FDA accelerated approvals are contingent on the results of a subsequent confirmatory trial, and the EV-301 trial (NCT03474107) is a confirmatory trial for the accelerated approval of enfortumab vedotin.

Seagen and Astellas previously reported data from EV-301 in a press release, showing that the ADC reduced the risk of death by 30% compared with chemotherapy in patients with locally advanced or metastatic urothelial cancer previously treated with platinum-based chemotherapy and a PD-1/PD-L1 inhibitor (HR, 0.70; P = .001).4 Enfortumab vedotin also reduced the risk of disease progression or death by 39% (HR, 0.61; P <.00001).

The global, multicenter, open-label, phase 3 EV-301 trial randomized patients to enfortumab vedotin or physician's choice of either docetaxel, paclitaxel, or vinflunine. The target enrollment was approximately 600 patients.

The companies plan to present additional data from EV-301 at an upcoming medical meeting.

References

1. Seagen and Astellas Announce Positive Topline Results from Second Cohort of Patients in Phase 2 Pivotal Trial of PADCEV® (enfortumab vedotin-ejfv) in Advanced Urothelial Cancer. PostedOctober 12, 2020. Accessed October 12, 2020. https://bit.ly/3iLKeoQ.

2. O’Donnell MD, Galsky JE, Petrylak DP, et al. EV-201: Long-term results of enfortumab vedotin monotherapy for locally advanced or metastatic urothelial caner previously treated with platinum and PD-1/PD-L1 inhibitors. Poster presented at: European Society of Medical Oncology Virtual Congress 2020; September 17-20, 2020. Abstract 746P.

3. FDA grants accelerated approval to enfortumab vedotin-ejfv for metastatic urothelial cancer. FDA. Published December 18, 2019. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-grants-accelerated-approval-enfortumab-vedotin-ejfv-metastatic-urothelial-cancer. Accessed October 12, 2020.

4. Seattle Genetics and Astellas Announce PADCEV® (enfortumab vedotin-ejfv) Significantly Improved Overall Survival in Phase 3 Trial in Previously Treated Locally Advanced or Metastatic Urothelial Cancer [news release]. Bothell, Washington and Tokyo. Published September 18, 2020. https://bwnews.pr/3343rxD. Accessed October 12, 2020.