Limited data compare first-line carboplatin-based chemotherapy and immune checkpoint blockade in cisplatin-ineligible metastatic urothelial carcinoma (mUC) patients. The primary evidence guiding treatment decisions was a recent Food and Drug Administration/European Medicines Agency safety alert based on emerging data from two ongoing phase III trials, reporting shorter survival in programmed death-ligand 1 (PD-L1)-negative patients receiving immunotherapy. Final results from these trials are unknown.

To compare survival in cisplatin-ineligible mUC patients receiving first-line immunotherapy versus those receiving carboplatin-based chemotherapy.

We conducted a retrospective cohort study of 2017 mUC patients receiving first-line carboplatin-based chemotherapy (n = 1530) or immunotherapy (n = 487) from January 1, 2011 to May 18, 2018 using the Flatiron Health electronic health record-derived database.

The primary outcomes were overall survival (OS), comparing 12- and 36-mo OS, and hazard ratios before and after 12 mo. Propensity score-based inverse probability of treatment weighting (IPTW) was used to address confounding in Kaplan-Meier and Cox regression model estimates of comparative effectiveness.

IPTW-adjusted OS rates in the immunotherapy group were lower at 12 mo (39.6% [95% confidence interval {CI} 34.0-45.3%] vs 46.1% [95% CI 43.4-48.8%]) but higher at 36 mo (28.3% [95% CI 21.8-34.7%] vs 13.3% [95% CI 11.1-15.5%]) relative to the chemotherapy group. Immunotherapy treatment demonstrated inferior OS during the first 12 mo relative to carboplatin-based chemotherapy (IPTW-adjusted hazard ratio [HR] 1.37, 95% CI 1.15-1.62), but superior OS beyond 12 mo (IPTW-adjusted HR 0.50, 95% CI 0.30-0.85). Limitations include retrospective design and potential unmeasured confounding.

In the setting of mUC, clinicians and patients should carefully consider how to balance the short-term benefit of chemotherapy against the long-term benefit of immunotherapy.

To determine the optimal first-line therapy for metastatic bladder cancer patients who are unfit for cisplatin, we compared carboplatin-based chemotherapy versus immunotherapy using real-world data. Survival in the 1st year of treatment was lower with immunotherapy relative to chemotherapy, but for patients surviving beyond the 1st year, immunotherapy was superior.

European urology. 2019 Jul 27 [Epub ahead of print]

Emily Feld, Joanna Harton, Neal J Meropol, Blythe J S Adamson, Aaron Cohen, Ravi B Parikh, Matthew D Galsky, Vivek Narayan, John Christodouleas, David J Vaughn, Rebecca A Hubbard, Ronac Mamtani

Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA, USA. Electronic address: ., Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA., Flatiron Health, New York, NY, USA., Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA, USA., Tisch Cancer Institute, Mount Sinai, New York, NY, USA.