Concurrent cisplatin should remain the standard treatment over cetuximab for patients with locoregionally advanced head and neck squamous cell carcinoma, according to a large comparative phase 3 trial.
Based on the results of an interim analysis of the ARTSCAN III clinical trial, the independent safety data monitoring committee recommended early closure of the study because the results of the study suggest that cetuximab may be inferior to cisplatin.
“This study supports previous retrospective and prospective studies that suggest that concurrent cisplatin with radiation is superior to regimens with concurrent cetuximab in locally advanced head and neck cancers,” commented Sachin Jhawar, MD, MSCI, assistant professor in the department of radiation oncology at Ohio State University Comprehensive Cancer Center, Columbus. “While the previous studies De-ESCALaTE HPV and RTOG 1016 were specific to HPV [human papillomavirus]-positive cancers, this study allowed non–virally mediated tumors, though the majority of cases were HPV related.”
The new study also used a lower-dose weekly regimen of cisplatin than the other two studies, noted Dr. Jhawar. Early trials used a cisplatin dose of 100 mg/m2 every 3 weeks, but “the field is moving toward a dose of 40 mg/m2 weekly, the dose use in the Swedish study. This study had an interesting second randomization of radiation dose-escalation for more advanced primary T stage tumors, but because the study ended early it is difficult to fully interpret those results.”
Swedish researchers, led by Maria Gebre-Medhin, MD, PhD, department of hematology, oncology, and radiation physics, Skåne University Hospital, Lund, Sweden, performed an open-label, randomized, controlled, phase 3 study of patients with locoregionally advanced head and neck squamous cell carcinoma. The patients received IV cetuximab 400 mg/m2 1 week before the start of radiation therapy followed by 250 mg/m2 per week, or weekly IV cisplatin 40 mg/m2 during radiation therapy.
The study results were published in the Journal of Clinical Oncology.
The study was prematurely closed after an unplanned interim analysis when 298 patients had been randomly assigned. The cumulative incidence of locoregional failures at 3 years was more than twice as high in the cetuximab group (23%), compared with the cisplatin group (9%; P = .0036). At 3 years, overall survival was higher in the cisplatin (88%) group than in the cetuximab group (78%), but the difference was not significant (P = .086). The cumulative incidence of distant failures did not differ between the treatment groups, and the toxicity burden was similar.
“Concurrent cisplatin led to improved locoregional control and event-free survival with a trend toward improved overall survival. The types of toxicity were different, as would be expected with the different drug mechanisms, but the rate of toxicity was not,” said Dr. Dr. Jhawar. “Interestingly, the benefit of cisplatin seemed to be limited to patients with p16-positive oropharyngeal cancer. There was clinical equipoise in the p16-negative oropharyngeal cancer group and in the non–oropharyngeal cancer group. The numbers were small, but this is intriguing and suggests that there is more work to be done in this group of patients to tease out if we can escalate or use alternative therapy.”
Cisplatin has been repeatedly proven to be superior in selected populations. The next steps, said Dr. Jhawar, include defining “optimal regimens in cisplatin-ineligible populations based on age, performance status, kidney function, hearing loss, neuropathy, and HIV/AIDS; improvements with new targeted therapies and immunotherapies; and deescalation of systemic and/or radiation regimens in the best outcome groups, such as low-risk HPV-positive patients. And we are going to see more personalized medicine with genetic testing of tumors.”
When patients are ineligible for cisplatin, no optimal regimens have been defined as yet. At Ohio State, Dr. Jhawar and colleagues use carboplatin therapy.
For practicing oncologists, Dr. Jhawar said the bottom line is “patients who are eligible should receive concurrent cisplatin therapy for locoregionally advanced head and neck cancer.”
The ARTSCAN III study was funded by the Swedish Cancer Society and the Mrs. Berta Kamprad Cancer Foundation. One of the study’s coauthors reported a leadership role in ScandiDos. The other authors reported they had no conflicts. Dr. Jhawar reported he had no conflicts of interest.