Kura Oncology (Nasdaq: KURA) released updated Phase 1a results from its FIT-001 clinical trial, showing clinical activity of darlifarnib combined with cabozantinib in patients with advanced clear cell renal cell carcinoma (ccRCC). The data were presented at the 2026 Kidney Cancer Research Summit in Boston.

In 34 cabozantinib-naïve ccRCC patients who had been previously treated, the objective response rate ranged from 33% to 50% across evaluated darlifarnib dose levels. Median progression-free survival was 13 months across pooled dose levels. Median duration of response was not estimable at most dose levels because multiple responses remained ongoing at the time of data cut-off. More than half of patients remained on treatment at data cut-off.

Across 72 RCC patients evaluated for safety, the combination's tolerability profile was described as manageable and consistent with the known profiles of the individual agents. Neutropenia was managed with dose interruption, reduction, and supportive care.

"The response rates and progression-free survival observed with darlifarnib plus cabozantinib are encouraging in this refractory, pretreated, cabozantinib-naïve population, particularly given the limited treatment options after prior immunotherapy, immune checkpoint inhibitors, and VEGFR-targeted therapy," said Adanma Ayanambakkam, M.D., of the Stephenson Cancer Center at the University of Oklahoma Health Sciences Center.

Kura is currently enrolling patients in the U.S. and European Union in a randomized Phase 1b portion of FIT-001, which compares darlifarnib plus cabozantinib against cabozantinib alone in cabozantinib-naïve, refractory ccRCC patients. The Phase 1b study is designed to identify a recommended Phase 3 dose for a planned registrational study in 2028.

Darlifarnib is a farnesyl transferase inhibitor that inhibits farnesylation of RHEB, resulting in selective mTORC1 inhibition. The information is based on a press release issued by Kura Oncology.