Background: Treatment of advanced urothelial carcinoma (mUC) has improved following approvals of PD-1/PD-L1 inhibitors. Platinum chemotherapy remains the standard-of-care in the first-line (1L). Cisplatin (Cis) regimens are accepted to be superior to carboplatin (Carbo) regimens for patients (pts) who are Cis-eligible. We sought to evaluate if differences in efficacy of 1L Cis vs. Carbo have meaningful impact on overall survival (OS) in the era of second-line (2L) immunotherapy (IO). Methods: We conducted a retrospective, observational cohort study to compare OS for pts treated with 1L Cis or Carbo combined with gemcitabine (Gem) followed by 2L IO using patient-level data from the nationwide Flatiron Health electronic health record (EHR)-derived de-identified database. Pts included were diagnosed with mUC between 9/1/2015 and 9/15/2020. 2L IO was defined as single-agent atezolizumab, avelumab, durvalumab, nivolumab, or pembrolizumab. OS was calculated from start of 1L and 2L therapy and compared using Kaplan-Meier curves. Time to 2L IO was calculated from start of 1L to start of IO. Adjusted OS was calculated using multivariable Cox regression models, adjusting for age, gender, race, ECOG performance status, primary site, prior cystectomy, smoking status, and year of diagnosis. Results: A total of 1882 pts were included, 924 (49.1%) received Gem/Cis and 958 (50.9%) received Gem/Carbo in 1L. A similar percentage of pts did not receive any 2L therapy following Gem/Cis (46.4%) or Gem/Carbo (46.0%). Our analysis focused on the 780 pts (41.4%) who received 2L IO—381 after Gem/Cis and 399 after Gem/Carbo. Median follow-up time for the group was 35 months (mo). Pts in the Gem/Cis cohort were younger, had better performance status and lower incidence of upper tract disease (Table). OS from start of 1L therapy was numerically longer in pts who received Gem/Cis compared to Gem/Carbo on unadjusted (median 18.0 v 16.2 mo, p = 0.06) and adjusted analyses (HR = 0.83, 95% CI 0.69-1.00, p = 0.055) but neither result was statistically significant. Time to 2L IO was longer for pts receiving Gem/Cis (6.5 mo) vs Gem/Carbo (5.5 mo, p = 0.008). Survival time on 2L IO did not differ significantly by 1L regimen (Gem/Cis 8.0 mo vs Gem/Carbo 8.2 mo p = 0.36). Conclusions: Real world data suggests that in pts with mUC who are able to receive second-line IO, the choice of first-line platinum chemotherapy may not provide a distinguishable OS benefit. Despite methodologic limitations of this data, a greater focus in discussions with patients on toxicity associated with cisplatin vs carboplatin may be warranted.
Benjamin Miron, Elizabeth A. Handorf, Kevin Zarrabi, Matthew R. Zibelman, Pooja Ghatalia, Fern Anari, Elizabeth R. Plimack, Daniel M. Geynisman
Fox Chase Cancer Center, Philadelphia, PA; Fox Chase Cancer Center, Department of Hematology and Oncology, Philadelphia, PA
Source: Miron B., Handorf EA., Zarrabi K. et al. "Influence of First-Line Chemotherapy Regimen on Survival Outcomes of Patients with Advanced Urothelial Carcinoma Who Receive Second-Line Immunotherapy." Journal of Clinical Oncology. Journal of Clinical Oncology 39, no. 15_suppl (May 20, 2021) 4535-4535.
Read an Expert Commentary by Bishoy Faltas, MD
