The investigational agent tipifarnib shows promise in patients with head and neck cancer who have a certain gene mutation.
An investigational therapy could be promising treatment for patients with head and neck squamous cell carcinoma (HNSCC) who have the HRAS gene mutation, according to study data presented during the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics.
Tipifarnib is a farnesyl transferase inhibitor, which inhibits a wide range of target proteins, including RAS — a protein that is commonly abnormally active in cancer. Some studies have shown that HRAS-mutant cancer may be susceptible to the drug, according to Dr. Alan L. Ho, a medical oncologist at Memorial Sloan Kettering Cancer Center in New York City. The HRAS mutation is present in tumors of about 5%-8% of patients with advanced HNSCC, according to a press release.
In a phase 2 clinical trial, 33 patients — 23 with HNSCC and 10 with squamous cell carcinomas (SCC) — were enrolled. The patients’ disease relapsed or became refractory, meaning the cancer became resistant at the beginning of or during treatment. In addition, patients received at least two prior treatments but had progressed on them. During a 28-day cycle, patients were given tipifarnib twice daily during alternate weeks.
“If this trial is successful, tipifarnib could represent a targeted drug treatment personalized to the genomics of HNSCC patients’ tumors,” Ho said in a press release.
The trial examined overall response rate and median progression-free survival, or the time during or after treatment where a patient lives without disease worsening. The researchers amended their population to include patients most likely to respond to treatment by including those whose tumors had HRAS mutations.
Among the 15 patients with HNSCC, the overall response rate was 53%, and this included eight partial responses and five stable disease. Median progression-free survival in HNSCC patients was 5.4 months.
“These results are very gratifying, considering our trial is targeting patients who have stopped responding to other treatments,” Ho said. “Tipifarnib is safe and well tolerated even in patients who have received multiple lines of previous therapies.”
The most commonly experienced treatment-related side effects greater than grade 3 included blood and lymphatic system disorders, gastrointestinal disorders and renal disorders, which study authors said were manageable.
However, the researchers noted that the small size of the study is a limitation and, therefore, more patients need to be treated to establish the effectiveness of tipifarnib.
“The success of the trial also speaks to the promise of utilizing genomic sequencing of diseases to identify highly effective therapies that are personalized to the specific biology of each individual patient’s tumor,” Ho said.