Preliminary results from a phase II open-label trial of tipifarnib, a farnesyltransferase inhibitor, in patients with HRAS-mutant head and neck squamous cell carcinoma (HNSCC) were presented by Alan L. Ho, MD, PhD, of Memorial Sloan Kettering Cancer Center, at the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics, held October 26–30 in Philadelphia (Abstract LBA-10).
The annual symposium is hosted by the American Association for Cancer Research (AACR), National Cancer Institute (NCI), and European Organisation for Research and Treatment of Cancer (EORTC).
Four out of six evaluable patients with HRAS-mutant HNSCC enrolled in the study achieved a confirmed partial response as defined by standard RECIST criteria. In addition, as of the data cutoff date of October 4, 2017, 4 patients remained on study in cycles 21, 7, 5, and 3. The patients in cycles 21, 7, and 5 had all experienced partial responses, whereas the patient in cycle 3 experienced stable disease as of the first response assessment in cycle 2. One patient with a confirmed partial response remained on study through cycle 20 and withdrew in cycle 21 with progressive disease. Another patient experienced a best response assessment of stable disease and withdrew from the study in cycle 8.
Tipifarnib has demonstrated clinical activity in previously treated patients, including those who have had disease progression on chemotherapy with or without cetuximab (Erbitux) or immunotherapy.
The majority of adverse events reported by the investigators have been mild to moderate and are consistent with the adverse event profile previously reported for tipifarnib.
“The responses, durability, and safety data with tipifarnib clearly suggest this is an important drug candidate for patients with HRAS-mutant head and neck cancers,” said Dr. Ho. “We are excited to continue to follow these patients and treat additional HRAS-mutant patients in the ongoing phase II trial.”
“The consistent clinical activity of tipifarnib in HNSCC patients with HRAS mutations is very encouraging,” said Antonio Gualberto, MD, PhD, Chief Medical Officer of Kura Oncology. “Based on these positive results, we continue to explore available options to rapidly advance the development of tipifarnib and subject to input from regulatory authorities, we plan to initiate a registration-enabling study in HRAS-mutant HNSCC in 2018.”
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