Overall survival results from a study with a combination of savolitinib and durvalumab for papillary renal cell carcinoma (RCC) patients were reported at the American Society of Clinical Oncology (ASCO) Genitourinary (GU) Cancers Symposium held in San Francisco last weekend.

Metastatic papillary RCC has poor outcomes and there is need for new treatments. In this phase 1/2 study (CALYPSO), a combination of savolitinib and durvalumab (PD-L1 inhibitor) were investigated for the treatment of metastatic papillary RCC. Savolitinib is a c-MET inhibitor that blocks the effects of a protein called c-MET tyrosine kinase, which is involved in new blood vessel growth essential for cancer cells to divide and grow. These treatments starve the tumour by stopping the development of a new blood supply (angiogenesis). Doctors call treatments that interfere with the development of a blood supply anti-angiogenic agents. Durvalumab is a type of immune checkpoint inhibitor – an immunotherapy drug that boosts the body’s immune response to cancer.

Forty-one patients with papillary RCC were treated in this study. At a median follow up of 14.3 months, the overall response rate was 27%, median progression-free survival was 4.9 months, and median overall survival was 12.3 months. For patients who had not been previously treated (27 patients), the response rate was 33% and median overall survival was 12.3 months. The treatment seemed relatively well tolerated, with 34% of patients reporting severe or life-threatening adverse events. Patients who were positive for PD-L1 and c-MET receptors on their cancer cells did not have higher response rates or longer overall survival.

In conclusion, although the numbers of patients in this trial were small, the combination of durvalumab and savolitinib has clinical activity with encouraging response rates and survival outcomes in patients with metastatic papillary RCC. Furthermore, outcomes were not influenced by the presence of biomarkers for PD-L1 or c-MET.

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