Comparative Effectiveness of Front-Line Ipilimumab and Nivolumab or Axitinib and Pembrolizumab in Metastatic Clear Cell Renal Cell Carcinoma.

Background: Treatment of metastatic renal cell carcinoma (mRCC) is rapidly evolving with new combination therapies demonstrating improved response rates and survival. There are no head-to-head prospective trials comparing an immunotherapy doublet with an immunotherapy/tyrosine-kinase inhibitor-based combination. We compare real-world outcomes in patients treated with axitinib/pembrolizumab (axi/pembro) or ipilimumab/nivolumab (ipi/nivo). The primary endpoints were overall-survival (OS) and real-world progression-free survival (rwPFS).

Patients And Methods: We used a de-identified database to select patients diagnosed with clear cell mRCC and treated with front-line axi/pembro or ipi/nivo from 2018 to 2022. Analyses are adjusted using propensity score-based inverse probability of treatment weighting, balancing age, gender, insurance, race, IMDC risk, and nephrectomy status. We compared survival by treatment groups using weighted and unweighted Kaplan-Meier curves with log-rank tests and weighted Cox proportional hazards regressions.

Results: We included a total of 1506 patients with mRCC who received frontline axi/pembro (n = 547) or ipi/nivo (n = 959). Median follow-up time was 20.0 months (range: 0.2-47.6). Baseline demographics were similar between the 2 cohorts. Adjusted median OS for the full population was 28.9 months for axi/pembro and was 24.3 months for ipi/nivo (P = .09). Twenty-four-month survival was 53.8% for axi/pembro treated patients and 50.2% for ipi/nivo treated patients. rwPFS was 10.6 months for axi/pembro treated patients and 6.9 months for ipi/nivo treated patients. Treatment with axi/pembro conferred improved survival in the IMDC favorable risk strata, with no significant difference in survival observed within the full cohort.

Conclusions: In this retrospective, real-world study of patients treated with front-line combination therapy, patients with IMDC favorable risk disease had better survival when treated with axi/pembro compared to ipi/nivo. However, survival for the entire population and the 24-month median overall survival were not statistically different between treatment groups. Longer follow-up is necessary to discern any emerging significant differences.