Merck, Pfizer's Drug Combo 'Rewrites the Standard of Care' in Bladder Cancer

The new data shows the combo therapy significantly improved survival and treatment response in a late-stage muscle-invasive bladder cancer study.

Published on Mar. 2, 2026

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A combination of Merck's Keytruda and Pfizer's Padcev significantly improved survival and treatment response in a late-stage muscle-invasive bladder cancer study, potentially changing the treatment paradigm in this indication. The drug combo cut the risk of disease progression, recurrence or death by 47% and lowered the risk of death from any cause by 35% versus standard of care.

Why it matters

The new findings could help Merck and Pfizer build toward regulatory filings for the drug doublet, providing a potential chemotherapy-free treatment option for patients with muscle-invasive bladder cancer, including those eligible for cisplatin.

The details

The results come from the Phase 3 EV-304 study (also called KEYNOTE-B15), which enrolled 808 patients with muscle-invasive bladder cancer (MIBC) eligible for cisplatin treatment. At the time of surgery, the pathological complete response rate hit 55.8% in patients treated with Merck and Pfizer's doublet, as compared with 32.5% in the control arm.

  • The new data was presented on March 2, 2026 at the American Society of Clinical Oncology Genitourinary Cancers Symposium in San Francisco.
  • In October 2025, the partners released data from the Phase 3 KEYNOTE-905 study, which similarly combined Keytruda and Padcev for the treatment of MIBC in patients not eligible for or denied cisplatin chemotherapy.

The players

Merck

An American pharmaceutical company that developed the PD-1 inhibitor Keytruda.

Pfizer

An American multinational pharmaceutical corporation that developed the antibody-drug conjugate Padcev.

Truist Securities

An investment banking firm that provided analysis on the new data.

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What they’re saying

“We think the KEYNOTE-B15 data, together with KEYNOTE-905 positions Keytruda plus Padcev as the likely go-to option in MIBC.”

— Truist Securities, Analysts (Truist Securities)

“The drug combo, consisting of the PD-1 inhibitor Keytruda and the antibody-drug conjugate Padcev, 'rewrites the standard of care in [muscle-invasive bladder cancer].'”

— Truist Securities, Analysts (Truist Securities)

What’s next

The new data will help Merck and Pfizer build toward regulatory filings for the drug doublet, providing a potential chemotherapy-free treatment option for patients with muscle-invasive bladder cancer.

The takeaway

The combination of Merck's Keytruda and Pfizer's Padcev has the potential to significantly improve outcomes for patients with muscle-invasive bladder cancer, including those eligible for cisplatin, by offering a chemotherapy-free treatment alternative that could become the new standard of care.