Finally, a drug to benefit rare kidney cancer

Washington DC: People suffering from advanced kidney cancer, we have some good news for you.

According to a recent study, some patients with a form of advanced kidney cancer that carries a poor prognosis benefited from an experimental drug targeted to an abnormal genetic pathway causing cancerous growth.

Savolitinib, the targeted drug showed linical activity in patients with metastatic papillary renal cell carcinoma (PRCC) whose tumors were driven by overactivity of the MET signaling pathway.

But, the drug was not effective for patients whose tumors lacked the MET abnormality.

The results of from a single-arm, multicenter phase II clinical trial, suggest that savolitinib holds promise as a personalized treatment for a subgroup of patients with metastatic papillary renal cell carcinoma, according to the researchers.

In the US alone, about 6,400 cases of PRCC are expected to be diagnosed in 2017, compared to a total of 64,000 cases of kidney cancers. The majority of them are classified as clear cell renal cell cancers.

Papillary renal cell carcinoma are non-clear cell kidney cancers. No good treatments exist for advanced or metastatic PRCC.

The current trial tested savolitinib, a potent and selective MET inhibitor, in 109 patients with locally advanced or metastatic PRCC. Of the 109 patients, 40 percent had tumors driven by MET, 42 percent had tumors that did not rely on MET, and MET status was unknown in 17 percent of patients.

When the results were analyzed, 18 percent of patients with MET-driven cancers had significant shrinkage of their tumors, and 50 percent had stable disease.

By contrast, none of the patients with MET-independent tumors had shrinkage response, and only 24 percent had stable disease.

In addition, the length of time after treatment before the cancer began growing was significantly longer in the MET-driven tumor group - 6.2 months versus 1.4 months.

According to the authors of the study, "These data support the hypothesis that savolitinib has antitumor activity in patients with MET-driven papillary renal cell carcinoma. Our study identified a defined molecular group and highlights the prevalence of MET-driven disease in this rare population of RCC patients."

Although some patients had their dosage of savolitinib reduced and two patients discontinued treatment because of side effects, the researchers said the drug was generally well-tolerated.