Multicenter phase 2 trial of savolitinib plus durvalumab for metastatic papillary renal cancer: final results of CALYPSO

The multicenter phase 2 CALYPSO study demonstrated activity of savolitinib plus durvalumab in MET-driven papillary renal cancer (PRC). Final results of CALYPSO have now been published. At a median follow-up of 41 months, objective response rate was 34% (95% CI 20.0-51.0) in the ITT population (n=41) and 53% (28.0-77.0) in the MET-driven patients (n=17); median progression-free survival was 6.5 months (2.7-12.0) and 13,9 months (2.9-23.8), respectively, and median overall survival (OS) was 18.3 months (7.3-30.7) and 27.4 months (9.3-37.4), respectively. PD-L1 and tumor mutational burden status did noet correlate with response. Baseline ctDNA positivity (10/21) correlated with shorter OS (median 7.3 versus 33.3 months) while ctDNA clearance (median 31.3 versus 7.2 months) and mean variant allele frequenct reduction (median 31.3 versus 15.5 months) correlated with improved OS. The authors conclude that the combination of savolitinib and durvalumab showed favorable OS results in MET-driven PRC.