SAN DIEGO – July 27, 2026
Kura Oncology, Inc. has reported updated Phase 1a clinical data from the ongoing FIT-001 trial demonstrating durable antitumor activity of darlifarnib combined with cabozantinib in cabozantinib-naïve patients with advanced clear cell renal cell carcinoma (ccRCC). The results, presented at the 2026 Kidney Cancer Research Summit (KCRS) in Boston, showed objective response rates of up to 50%, a median progression-free survival (PFS) of 13 months, and durable responses across multiple dose levels in previously treated patients with locally advanced or metastatic disease. The combination therapy was well tolerated, with a safety profile consistent with the known profiles of the individual medicines. The findings support the continued development of darlifarnib plus cabozantinib, with the ongoing randomized Phase 1b study expected to identify the recommended dose for a planned Phase 3 registrational trial.
Combination Therapy Demonstrates Encouraging Clinical Activity
The updated Phase 1a FIT-001 data included 34 cabozantinib-naïve patients with advanced clear cell renal cell carcinoma, many of whom had previously received immunotherapy and other targeted treatments. Across the evaluated dose levels, the objective response rate ranged from 33% to 50%, while the median progression-free survival reached 13 months. In addition, the median duration of response could not yet be estimated at several dose levels because many patients remained in ongoing response at the time of data analysis. More than half of the participants continued receiving treatment at the data cutoff, demonstrating sustained clinical benefit. Investigators noted that these outcomes compare favorably with historical results reported for VEGFR-targeted tyrosine kinase inhibitors (TKIs) and HIF-2α inhibitor monotherapies used in later-line renal cell carcinoma treatment.
Manageable Safety Profile Supports Continued Clinical Development
Safety analyses involving 72 patients demonstrated that the combination of darlifarnib and cabozantinib was generally well tolerated across all evaluated dose levels. The adverse event profile remained consistent with the established safety characteristics of each individual therapy, with neutropenia successfully managed through dose interruptions, dose reductions, and supportive care after the dose-limiting toxicity evaluation period. Dr. Adanma Ayanambakkam of the University of Oklahoma Health Sciences Center stated that the encouraging response rates and progression-free survival observed in this difficult-to-treat patient population highlight the potential of the combination therapy, particularly for patients with limited treatment options following prior immunotherapy and VEGFR-targeted treatments. Continued patient follow-up is expected to further define the durability of these clinical responses.
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Randomized Phase 1b Trial Advances Toward Registrational Study
Building on the encouraging Phase 1a findings, Kura Oncology is actively enrolling patients in the United States and Europe into the randomized Phase 1b portion of the FIT-001 trial. The study compares darlifarnib plus cabozantinib with cabozantinib alone in cabozantinib-naïve, refractory clear cell renal cell carcinoma patients to determine the optimal dose combination for future development. According to Chief Medical Officer Dr. Mollie Leoni, the study will establish the recommended Phase 3 dose and support the company’s planned registrational trial in 2028. Darlifarnib, a next-generation farnesyl transferase inhibitor, selectively inhibits mTORC1 through RHEB farnesylation blockade, offering a novel mechanism designed to enhance the activity of VEGFR-targeted therapies and potentially improve treatment outcomes for patients with advanced kidney cancer.
Source: Kura Oncology press release
