SUMMARY: The American Cancer Society estimates that in the United States for 2024, about 83,190 new cases of bladder cancer will be diagnosed and approximately 16,840 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. As of the data cutoff date, the median duration of follow-up for survival was 17.2 months.
The PFS was significantly longer in the Enfortumab vedotin plus Pembrolizumab group compared to the chemotherapy group (median duration 12.5 months versus 6.3 months; HR=0.45; P<0.001), representing a 55% reduction in the risk of disease progression or death. Enfortumab vedotin plus Pembrolizumab also substantially improved median OS, and the median OS was 31.5 months compared to 16.1 months with chemotherapy (HR=0.47; P<0.001) representing a 53% reduction in the risk of death. These PFS and OS benefits were consistent between the intention-to-treat population and all the prespecified subgroups, including those defined according to Cisplatin eligibility status and PD-L1 expression status. The Overall Response Rate (ORR) in the Enfortumab vedotin plus Pembrolizumab group was 67.7%, significantly higher than the 44.4% ORR observed with chemotherapy alone (P<0.001), with a Complete Response rate of 29.1% versus 12.5% respectively. The median Duration of Response was Not Reached in the Enfortumab vedotin plus Pembrolizumab group and was 7.0 months in the chemotherapy group.
Treatment-related adverse events of Grade 3 or higher occurred in 55.9% of the patients in the Enfortumab vedotin plus Pembrolizumab group, and was 69.5% in the chemotherapy group. The most common treatment-related adverse events of any grade in the Enfortumab vedotin plus Pembrolizumab group were peripheral sensory neuropathy, pruritus and alopecia, whereas the most common such events in the chemotherapy group were anemia, neutropenia and nausea.
It was concluded that treatment with Enfortumab vedotin plus Pembrolizumab resulted in significantly better outcomes than 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.
Enfortumab Vedotin and Pembrolizumab in Untreated Advanced Urothelial Cancer. Powles T, Valderrama BP, Gupta S, et al. for the EV-302 Trial Investigators. N Engl J Med 2024;390:875-888.
