First-line therapy for metastatic renal cell carcinoma: A propensity score-matched comparison of efficacy and safety

Immune checkpoint inhibitor (ICI)-based combination therapy is a standard systemic treatment for metastatic renal cell carcinoma (mRCC). Although differential pharmacologic action between ICI+ICI and ICI+tyrosine kinase inhibitor (TKI) combinations may affect outcomes, comparative studies using real-world data are few.

We retrospectively analyzed the records of 447 mRCC patients treated with 1st-line ICI-based combinations at multiple institutions between January 2018 and August 2023, and selected 320 patients diagnosed with clear cell RCC (ccRCC) for further study. Cohorts were matched using one-to-one propensity scores based on IMDC risk classification. Overall survival (OS), progression-free survival (PFS), objective response rates (ORRs), and treatment-related adverse events (TrAE) were compared.

The matching process yielded 228 metastatic ccRCC patients treated with ICI+ICI (n = 114) or ICI+TKI (n = 114). Median OS was 53 months (95%CI: 33-NA) in patients treated with ICI+ICI and was not reached (95%CI: 43-NA) with ICI+TKI (P = 0.24). Median PFS was significantly shorter for ICI+ICI (13 months, 95%CI: 7-25) than for ICI+TKI (25 months, 95%CI: 13-NA) (P = 0.047). There were no differences in second-line PFS for sequential therapy after 1st-line combinations of ICI+ICI or ICI+TKI (6 vs. 8 months, P = 0.6). There were no differences in ORR between the 2 groups (ICI+ICI: 51% vs. ICI+TKI: 55%, P = 0.8); the progressive disease (PD) rate was significantly higher in patients treated with the ICI+ICI combination (24% vs. 11%, P = 0.029). The rate of any grade TrAE was significantly higher in patients treated with ICI+TKI (71% vs. 85%, P = 0.016), but we found no differences in severe TrAE between the 2 groups (39% vs. 36%, P = 0.8).

In a matched cohort of real-world data, we confirmed comparable OS benefits between ICI+ICI and ICI+TKI combinations. However, differential clinical behaviors in terms of PFS, PD rates, and TrAE between ICI-based combinations may enrich clinical decision-making.