A phase II study investigating the safety and efficacy of savolitinib and durvalumab in metastatic papillary renal cancer (CALYPSO).

Abstract

545 Background: Metastatic papillary renal cancer (PRC) has poor outcomes and there is need for new treatments. There is a strong rationale for investigating MET and PD-L1 inhibition in this disease. In this study, we investigate savolitinib (MET inhibitor) and durvalumab (PD-L1 inhibitor) together. Methods: This single arm phase I/II trial explored durvalumab and savolitinib at starting doses of 1500mg Q4W and 600mg OD respectively, with a 4wk savolitinib run-in. Treatment naïve or previously treated patients with metastatic PRC were included. Response rate (RR) (RECIST v1.1) was the primary endpoint. Progression free survival (PFS), tolerability (CTCAE v4) and overall survival were secondary endpoints. Biomarkers were explored from archived tissue. Results: Dose escalation work identified a dose of durvalumab of 1500mg Q4W and savolitinib 600mg OD to take forward to phase II. Between Jan 2017 and Jul 2018, 42 patients were enrolled at this dose. 1 patient did not receive study treatment. The following analyses were performed on the remaining 41 patients. 12% of patients did not receive the combination (3 PD, 1 death, 1 PS deterioration). The median follow up was 8.9 months (95% CI: 6.9-10.9 months). IMDC good, intermediate and poor risk disease occurred in 29% (n=12), 63% (n=26), and 7% (n=3) patients respectively. Overall RR was 27% (11/41), while median PFS was 3.3 months (95% CI: 1.5-NR months). RR and median PFS in the previously untreated cohort (N=28) were 29% (8/28) and 12.0 months (95% CI: 1.5-NR months) respectively. Grade 3/4 toxicity occurred in 15 patients. Discontinuation for toxicity occurred in 3 patients, all due to liver toxicities. Biomarker work including PD-L1 and MET expression will be included in the analysis. Conclusions: The combination of savolitinib and durvalumab appears safe and associated with clinical activity in PRC. Clinical trial information: NCT02819596.