AstraZeneca (LSE/STO/NYSE: AZN) has reported positive results from the pivotal VOLGA trial assessing a bladder cancer treatment regimen of perioperative durvalumab (Imfinzi) combined with neoadjuvant enfortumab vedotin (Padcev; Pfizer, Astellas). Specifically, Imfinzi + Padcev demonstrated statistically significant improvements in both event-free survival and overall survival in muscle-invasive bladder cancer (MIBC) patients ineligible for cisplatin-based chemotherapy. The Phase III readout positions durvalumab as a potential treatment option in a population that has historically been limited to surgery alone.
The VOLGA trial specifics
The VOLGA trial is a Phase III, randomized, open-label, multi-centre global study enrolling 695 patients with muscle-invasive bladder cancer who were ineligible for or declined cisplatin, randomized 1:1:1 across three arms evaluated against radical cystectomy with or without approved adjuvant therapy.
A planned interim analysis produced two distinct results depending on arm. In Arm 2 — perioperative durvalumab combined with neoadjuvant enfortumab vedotin, followed by adjuvant durvalumab monotherapy — both co-primary endpoints of event-free survival and overall survival met statistical significance versus the comparator arm. In Arm 1, which added tremelimumab (Imjudo) to the durvalumab and enfortumab vedotin backbone, event-free survival also reached statistical significance, but the overall survival data showed only a favorable trend that did not cross the pre-specified significance threshold at this interim analysis. AstraZeneca said OS for Arm 1 will be formally reassessed at a subsequent analysis.
No specific numerical values — including hazard ratios, median event-free survival, or p-values — were disclosed in the press release. Full data are expected to be presented at a forthcoming medical meeting.
The safety profile of durvalumab with or without tremelimumab plus enfortumab vedotin was described as consistent with the known profiles of each individual agent, with no new safety signals identified.
The MIBC treatment challenge
Approximately one in four patients diagnosed with bladder cancer has muscle-invasive disease, in which the tumor has penetrated the muscle wall of the bladder but has not spread to distant sites. Radical cystectomy — surgical removal of the bladder — remains the standard intervention, but up to half of patients with muscle-invasive bladder cancer are ineligible for cisplatin-based neoadjuvant chemotherapy due to impaired renal function or other comorbidities. For this group, the historical standard has been surgery alone, and roughly 50% of patients who undergo radical cystectomy experience disease recurrence.
Durvalumab is a human monoclonal antibody that binds PD-L1 and blocks its interaction with PD-1 and CD80, restoring antitumor T-cell activity. Enfortumab vedotin is a Nectin-4-directed antibody-drug conjugate that delivers the microtubule-disrupting payload monomethyl auristatin E intracellularly, causing mitotic arrest and cell death in Nectin-4-expressing tumor cells. The combination pairs direct cytotoxic tumor killing with immune checkpoint restoration, a mechanistic rationale that has driven interest in this pairing across urothelial cancer settings.
Tremelimumab, the CTLA-4-targeting antibody added in Arm 1, is designed to enhance T-cell priming upstream of PD-L1 blockade, theoretically deepening the immune response. The less conclusive OS result for Arm 1 at this interim analysis raises a question about whether the addition of tremelimumab provides incremental benefit in this perioperative context, though the data remain immature for a definitive interpretation.