Durable responses to immune checkpoint inhibitor-based regimens for metastatic clear cell renal cell carcinoma stratified by IMDC risk groups: A pooled analysis of four randomized phase 3 trials.

Abstract

Background: An immune checkpoint inhibitor (ICI) backbone is a standard of care for frontline metastatic clear cell renal cell carcinoma, involving either ICI doublet or tyrosine kinase inhibitor (TKI) with ICI. These phase 3 trials used a sunitinib control arm. The optimal regimen is uncertain.

Objective: To compare long-term responders of these trials using extended follow-up data stratified by International Metastatic RCC Database Consortium risk group.

Methods: Phase 3 trial data (CheckMate 214, KEYNOTE-426, CheckMate 9ER, and CLEAR) with a minimum follow-up of four years was used. Pseudo individual patient data (IPD) was obtained from Kaplan-Meier curves using the graph digitizer software IPDfromKM R package to extract coordinates of points on the curves and to apply a numerical algorithm to reconstruct progression-free survival (PFS) and overall survival (OS) results. Durable response (DR) was defined as PFS ≥ 24 months, extreme durable response (EDR) as PFS ≥ 36 months, and long-term OS as OS ≥ 48 months.

Results: For the favorable risk group, lenvatinib-pembrolizumab had the highest DR and EDR, while ipilimumab-nivolumab had the lowest DR, and cabozantinib-nivolumab had the lowest EDR; there was no difference in long-term OS among the regimens (p = 0.11). For the intermediate/poor risk group, lenvatinib-pembrolizumab also had the highest DR and EDR compared to other regimens with similar DR and EDR; there was also no difference in long-term OS among the regimens (p = 0.22).

Conclusion: TKI-ICI was overall associated with higher DR and EDR regardless of risk status compared to ICI doublet. Yet, OS at 48 months were similar when stratified by favorable versus intermediate/poor risk.