Among patients with recurrent and/or metastatic, squamous cell head and neck cancer, the addition of the targeted therapy Vectibix® (panitumumab) to chemotherapy does not result in significantly better survival than chemotherapy alone. The results of this Phase III clinical trial were made available in a press release from Amgen and will also be presented at an upcoming medical meeting.
Head and neck cancers originate in the tissues in or around the mouth, nose, and throat. Risk factors for head and neck cancer include smoking, alcohol consumption, and infection with high-risk types of human papillomavirus (HPV). Patients with head and neck cancer that has spread to other parts of the body or that has returned after initial treatment have limited treatment options, and researchers continue to explore new and more effective approaches to treatment.
Targeted therapies are anticancer drugs that interfere with specific pathways involved in cancer cell growth or survival. Some targeted therapies block growth signals from reaching cancer cells; others reduce the blood supply to cancer cells; and still others stimulate the immune system to recognize and attack the cancer cell. Depending on the specific “target,” targeted therapies may slow cancer cell growth or increase cancer cell death.
Vectibix inhibits cancer cell growth and survival by targeting a protein known as the epidermal growth factor receptor (EGFR). Vectibix has been approved for the treatment of EGFR-expressing, metastatic colorectal cancer that has progressed on or following fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy regimens. Vectibix appears to benefit only those patients whose cancers do not contain a mutation in a gene known as KRAS. KRAS mutations occur in an estimated 40-50% of metastatic colorectal cancers and can be identified by testing a sample of tumor tissue.
To explore the potential role of Vectibix in advanced head and neck cancers, researchers conducted a Phase III clinical trial among 658 patients with recurrent and/or metastatic squamous cell head and neck cancer. Patients received treatment with either chemotherapy alone or chemotherapy plus Vectibix. Chemotherapy consisted of cisplatin and 5-FU.
The primary outcome of interest was overall survival. Researchers also evaluated response rate and progression-free survival.
- Overall survival was 11.1 months among patients treated with chemotherapy plus Vectibix versus 9.0 months among patients treated with chemotherapy alone. This difference between groups did not meet the criteria for statistical significance, suggesting that it could have occurred by chance alone.
- Survival without cancer progression was 5.8 months among patients treated with chemotherapy plus Vectibix and 4.6 months among patients treated with chemotherapy alone.
- A response to treatment (a reduction in detectable cancer) occurred in 36% of patients treated with chemotherapy plus Vectibix and 25% of patients treated with chemotherapy alone.
- The most common side effects in the Vectibix group included nausea, rash, low white blood cell counts, and vomiting.
Detailed results from this study will be presented at the 35th European Society for Medical Oncology (ESMO) conference in October.
Though these results are disappointing for patients with head and neck cancer, Vectibix remains an important treatment option for selected patients with metastatic colorectal cancer.
Reference: Amgen News Release. Amgen announces top-line results of phase 3 head and neck cancer trial. August 11, 2010.