Adding pembrolizumab to first-line platinum-based chemotherapy in patients with metastatic urothelial carcinoma extended median overall survival to 21.8 months compared to 7.9 months with chemotherapy alone — a 13.9-month improvement — in the Phase 3 KEYNOTE-869 trial, establishing a new standard of care for this aggressive malignancy.

Bladder Cancer: An Undertreated Disease

Bladder cancer affects approximately 83,000 Americans annually, making it the sixth most common cancer in the United States. Metastatic urothelial carcinoma — which includes cancers of the bladder, ureter, and renal pelvis — has historically had poor outcomes, with median overall survival of 12 to 15 months with standard platinum-based chemotherapy. For patients ineligible for cisplatin due to renal dysfunction, outcomes are even worse.

Trial Design

KEYNOTE-869 enrolled 886 patients with previously untreated locally advanced or metastatic urothelial carcinoma at 180 sites globally. Patients were randomized 1:1 to receive gemcitabine plus cisplatin or carboplatin with or without pembrolizumab 200 mg every three weeks for up to 35 cycles.

Outcomes

Median overall survival was 21.8 months in the pembrolizumab arm vs 7.9 months in the chemotherapy-alone arm (HR 0.43, 95% CI 0.36-0.52, p<0.0001). Progression-free survival was 11.2 vs 5.8 months. Objective response rate was 68.4% vs 44.9%.

The survival benefit was consistent across all prespecified subgroups, including PD-L1 high and low expressors, cisplatin-eligible and -ineligible patients, and those with visceral vs non-visceral metastases — a finding of particular clinical importance as it suggests pembrolizumab benefit is not restricted to biomarker-selected patients.

Safety

Grade 3-4 treatment-related adverse events occurred in 61.2% of the combination arm vs 48.4% of chemotherapy alone. The most common severe immune-related adverse events included pneumonitis (4.8%), colitis (3.1%), and hepatitis (2.7%). Treatment discontinuation due to adverse events was 18.3% vs 9.1%.

Regulatory Status

The FDA approved pembrolizumab in combination with platinum-containing chemotherapy for first-line metastatic urothelial carcinoma in February 2026. European Medicines Agency review is ongoing. Several professional societies have already updated practice guidelines to reflect this new standard.

⚕️ Medical Disclaimer: This article is for informational purposes only. It does not constitute medical advice. Always consult a qualified healthcare professional before making health decisions.