Researchers have found that the small molecule inhibitor cabozantinib was found most effective in treating patients with metastatic papillary kidney cancer among three targeted drugs.

The findings, to be published in the journal The Lancet, found that patients receiving sunitinib went a median of 5.6 months before their cancer progressed; patients receiving savolitinib and crizotinib fared much worse overall. But cabozantinib, which inhibits VEGF receptors and AXL in addition to MET, gave patients a median of 9.2 months before their cancer progressed, the study indicated. "The magnitude of the response was surprising," said researcher Sumanta Pal from the City of Hope in the US said. "We still have a long way to go to help make patients' lives longer and better, but we do have a new standard treatment for these rare cancer patients," Pal added.

Mutations in the MET gene are a hallmark of this type of cancer, and there are new drugs that target the MET gene among other important signalling pathways, the researcher said. For the study, the team studied 147 eligible patients with papillary kidney cancer, most of whom had not received any prior treatment. Patients were randomly assigned to one of four treatment groups - those who took sunitinib and those who took one of the three MET target drugs -- cabozantinib, crizotinib, and savolitinib. The team wanted to see how long it would take patients' cancer to spread or return, a measure known as progression-free survival. In addition to the result, the team also found, 23 percent of patients had a significant reduction in the size of their tumour with cabozantinib. In contrast, only 4 percent of patients saw this kind of tumour response with sunitinib.