Astellas-Backed Bladder Cancer Trial Nears Key Data Moment After Study Completion

Astellas Pharma (ALPMF) announced an update on their ongoing clinical study.

Perioperative Immunotherapy Combo Challenges Chemotherapy in Bladder Cancer

The phase 3 trial KEYNOTE‑B15 / EV‑304, formally titled “A Phase 3, Randomized, Open-label Study to Evaluate Perioperative Enfortumab Vedotin Plus Pembrolizumab (MK-3475) Versus Neoadjuvant Gemcitabine and Cisplatin in Cisplatin-eligible Participants With Muscle-invasive Bladder Cancer,” compares a newer drug combo against standard chemotherapy before and after surgery in muscle-invasive bladder cancer. The main goal is to see if the newer approach improves the time patients stay free of major events such as recurrence or progression, which could set a new standard of care in a high‑risk cancer segment.

The study tests perioperative treatment (before and after surgery) with enfortumab vedotin and pembrolizumab, both given by infusion, against standard chemotherapy with gemcitabine and cisplatin. Enfortumab vedotin is an antibody‑drug conjugate designed to target cancer cells more directly, while pembrolizumab is an immunotherapy that helps the immune system attack tumors. Both are given around the time of radical cystectomy and lymph node removal, aiming to reduce cancer burden and cut relapse risk.

The trial is interventional, phase 3, and randomized, meaning patients are assigned by chance to either the new combination or standard chemotherapy. It uses a parallel design, so both groups are treated and followed at the same time. The study is open label, so doctors and patients know which treatment they receive, and the main focus is treatment benefit rather than diagnosis or prevention. The primary outcome is event‑free survival, a practical measure of how long patients avoid cancer‑related problems after starting therapy.

The study was first submitted in January 2021, marking the setup and launch phase for patient enrollment and site activation. The trial has now reached “Completed” status, indicating treatment and follow‑up needed for primary analysis are finished, although results have not yet been posted. The most recent update was submitted on February 4, 2026, signaling that data collection and internal analysis are active and that public disclosure of outcomes may be approaching. The estimated and primary completion dates align with this update cycle, which is often a precursor to conference data releases or regulatory filings.

For investors, this completed study is important to Astellas Pharma, Seagen, and Merck, all of which share stakes in enfortumab vedotin and pembrolizumab in bladder cancer. If the enfortumab‑pembrolizumab combo shows clear benefit over gemcitabine/cisplatin, it could expand use of these drugs from advanced disease into earlier, curative settings, increasing treatment duration and patient numbers. That would be a positive signal for Astellas’s oncology franchise and could support a higher valuation for its bladder cancer portfolio, while also reinforcing Merck’s KEYTRUDA growth story. A strong readout could pressure competitors in chemotherapy and other immunotherapies and reshape expectations for standard of care in muscle‑invasive bladder cancer. Conversely, a neutral or negative outcome would likely temper enthusiasm and weigh on sentiment toward future label expansion in earlier-stage disease.

This study is completed and recently updated, with further details and eventual results to be made available on the ClinicalTrials portal.

To learn more about ALPMF’s potential, visit the Astellas Pharma drug pipeline page.