Kura Oncology announced updated clinical outcome data from its RUN-HN study, a Phase 2 open-label, single-arm trial of tipifarnib in patients with HRAS mutant head and neck squamous cell carcinoma (HNSCC) whose disease had progressed after prior therapy. These data are being presented in an oral session at the American Society of Clinical Oncology (ASCO) Virtual Scientific Program.

At data cutoff, 21 patients with HRAS mutant HNSCC were enrolled, of whom 18 were evaluable for efficacy. Nine of the 18 evaluable patients achieved a confirmed partial response (PR), for an objective response rate (ORR) of 50% (95% CI, 26.0 to 74.0), with a median duration of response of 14.7 months. Median progression-free survival (PFS) was 5.9 months (95% CI, 3.5 to 19.2), compared to 2.8 months on the patients’ last prior therapy. Median overall survival (OS) was 15.4 months (95% CI, 7.0 to 46.4). Patients had a median of two prior lines of therapy (range 0-6). Robust activity was seen despite resistance to chemotherapy, immunotherapy and/or cetuximab.

ORR for three FDA-approved therapies for treatment of HNSCC in the second line range from 13-16%, with median PFS of 2-3 months and median OS of 5-8 months.

“It’s encouraging to see robust overall survival data for tipifarnib, which demonstrate a potentially meaningful development for HNSCC patients with HRAS mutations in the advanced setting,” said Alan Ho, M.D., Ph.D., of Memorial Sloan Kettering Cancer Center and principal investigator of the study. “These data add to the body of evidence emerging for tipifarnib in second line HNSCC patients, a patient population with very few treatment options and a high unmet need. These results also highlight the importance of tumor genomic profiling to identify patients with HRAS mutations who could potentially be suitable for tipifarnib treatment.”

Patients in the RUN-HN trial received tipifarnib at a starting dose of 600 or 900 mg orally twice daily on days 1-7 and 15-21 of 28-day cycles. Tipifarnib was generally well-tolerated. The most common grade 3 or 4 adverse events (AEs) seen in at least 10% of patients were cytopenias and GI disturbances.

“We believe a median overall survival of 15 months is unprecedented in this patient population and represents a substantial improvement compared to historical benchmarks with current standard of care,” said Troy Wilson, Ph.D., J.D., President and Chief Executive Officer of Kura Oncology. “Taken together, these data support our enhanced focus on patients with HRAS mutant HNSCC, a population in desperate need of effective new treatments, and reinforce our confidence in the ongoing AIM-HN registration-directed trial.”

The AIM-HN registration-directed trial of tipifarnib in patients with recurrent or metastatic HRAS mutant HNSCC is currently recruiting at approximately 90 clinical sites in the U.S., Europe and Asia. Patients interested in participating in this trial may talk to their doctor to have their tumor tested for the HRAS mutation for eligibility to enroll in this trial.