SUMMARY: The American Cancer Society estimates that in the United States for 2025, about 84,870 new cases of bladder cancer will be diagnosed and approximately 17,420 patients will die of the disease. Bladder cancer is the fourth most common cancer in men, but it is less common in women. Bladder cancer accounts for 90% of urothelial cancers, and urothelial cancer can also be found in the renal pelvis, ureter and urethra. Approximately 12% of urothelial cancer cases at diagnosis are locally advanced or metastatic.
Patients with urothelial carcinoma are currently treated in the first line setting with a Platinum based chemotherapy regimen, and a checkpoint Inhibitor (PD-1 or PD-L1 inhibitor) in the second line setting. However, approximately 50% of patients with advanced urothelial carcinoma are ineligible for Cisplatin-based chemotherapy due to toxicities, and responses are rarely durable. There is therefore a critical need for effective and tolerable first line treatment options in locally advanced or metastatic urothelial carcinoma.
Enfortumab vedotin-ejfv (PADCEV®) is a first-in-class Antibody-Drug Conjugate (ADC) that targets Nectin-4, a cell adhesion molecule highly expressed in urothelial cancers and other solid tumors. Nectin-4 has been implicated in tumor cell growth and proliferation. Following binding to Nectin-4 on the cell surface, Enfortumab vedotin becomes internalized and is processed by lysosomes, with the liberation of its cytotoxic payload, MonoMethyl Auristatin E (MMAE), which in turn disrupts microtubule assembly, leading to cell cycle arrest and apoptosis. Enfortumab vedotin resulted in significantly longer Overall Survival, Progression Free Survival, and a higher Overall Response Rate, than standard chemotherapy, in patients with locally advanced or metastatic urothelial carcinoma, who had previously received Platinum-based treatment and a PD-1 or PD-L1 inhibitor. Preclinical studies with Enfortumab vedotin have shown hallmarks of immune cell death potentially augmented by PD-1/PD-L1 inhibitors, and the rationale for this clinical trial was based on results from a previous cohort study.
Pembrolizumab (KEYTRUDA®) is a fully humanized, Immunoglobulin G4, anti-PD-1, monoclonal antibody, that binds to the PD-1 receptor and blocks its interaction with ligands PD-L1 and PD-L2. By doing so, it unleashes the tumor-specific effector T cells, and is thereby able to undo PD-1 pathway-mediated inhibition of the immune response. Pembrolizumab is the first agent to improve Overall Survival over chemotherapy, in the second line setting, for patients with recurrent, advanced urothelial carcinoma, and a significant proportion of patients who respond, have very durable responses.
EV-302 is a landmark Phase III, global, open-label, randomized trial comparing the efficacy and safety of Enfortumab vedotin and Pembrolizumab with the efficacy and safety of platinum-based chemotherapy, in patients with previously untreated locally advanced or metastatic urothelial carcinoma. A total of 886 eligible patients were randomly assigned in a 1:1 ratio to receive 3-week cycles of Enfortumab vedotin 1.25 mg/kg IV on days 1 and 8 and Pembrolizumab 200 mg IV on day 1 of every 3-week cycle (N=442) or chemotherapy consisting of Gemcitabine and either Cisplatin or Carboplatin (N=444), determined on the basis of eligibility to receive Cisplatin, for a maximum of 6 cycles. The maximum number of Pembrolizumab cycles allowed was 35 and there was no maximum number of cycles set for Enfortumab vedotin. The treatment groups were well balanced. The median age was 69 yrs and randomization was stratified according to eligibility to receive Cisplatin (eligible or ineligible), PD-L1 expression status (High-CPS 10 or more versus Low-CPS less than 10), and liver metastases (present or absent). The co-Primary end points were Progression Free Survival (PFS) and Overall Survival (OS) as assessed by Blinded Independent Central Review (BICR). Secondary end points included Overall Response Rate (ORR) as assessed by BICR, Duration of Response, and Safety.
In the primary analysis of EV-302 (KEYNOTE-A39) study, the combination of Enfortumab vedotin plus Pembrolizumab group nearly doubled median PFS (12.5 months versus 6.3 months) and OS (31.5 months versus to 16.1 months), when compared to platinum-based chemotherapy, in patients with previously untreated locally advanced or metastatic urothelial carcinoma.
In this report, the researchers reported the outcomes of EV-302 study after 1 year of additional follow-up (about 2.5 years of median follow-up), and an exploratory analysis of patients with confirmed Complete Response.
The PFS benefit with Enfortumab vedotin plus Pembrolizumab was maintained with an additional year of follow-up (12.5 versus 6.3 months; HR=0.48; P<0.00001). The OS benefit was also maintained with Enfortumab vedotin plus Pembrolizumab with a 49% reduction in the risk of death, when compared to platinum-based chemotherapy (33.8 versus 15.9 months; HR=0.51; P<0.00001). The PFS and OS benefit was observed across prespecified subgroups, including the Cisplatin-eligible and ineligible patients.
The ORR in the Enfortumab vedotin plus Pembrolizumab group was 67.5% versus 44.2% in the chemotherapy group (P<0.0.001) and the median Duration of Response was 23.3 months versus 7.0 months, respectively. A Complete Response was observed in 30.4% of patients treated with Enfortumab vedotin plus Pembrolizumab versus 14.5% among patients treated with chemotherapy. The median duration of Complete Response was not reached for Enfortumab vedotin plus Pembrolizumab and 15.2 months for chemotherapy. The probability of maintaining a Complete Response at 2 years with Enfortumab vedotin plus Pembrolizumab was 74%. For patients with a confirmed Complete Response, the 2-year PFS and OS rates were 78% and 95% in the Enfortumab vedotin plus Pembrolizumab group, respectively, versus 54% and 86% in the chemotherapy group, respectively.
It was concluded that, these data with longer follow up suggests that treatment with Enfortumab vedotin plus Pembrolizumab resulted in significantly superior outcomes, compared to chemotherapy, in patients with untreated locally advanced or metastatic urothelial carcinoma, emerging as a potential new standard of care, irrespective of Cisplatin eligibility. The results from this study mark a significant paradigm shift in the management of locally advanced or metastatic urothelial carcinoma, offering new hope for patients and clinicians alike.
EV-302: Updated analysis from the phase 3 global study of enfortumab vedotin in combination with pembrolizumab (EV+P) vs chemotherapy (chemo) in previously untreated locally advanced or metastatic urothelial carcinoma (la/mUC). Powles T, Van Der Heijden M, Loriot Y, et al. 2025 ASCO Genitourinary Cancers Symposium. Abstract 664. Journal of Clinical Oncology. Volume 43, Number 5_suppl February 2025.
