Is there a role for adjuvant cetuximab after radiotherapy (RT) plus cetuximab in patients (pts) with locally advanced squamous cell carcinoma of the oropharynx? A phase II randomized trial.

Abstract

5534 Background: Cetuximab combined with RT is a treatment option for locally advanced head and neck cancer, especially for oropharyngeal tumors. The objectives of this prospective, randomized, multicenter, phase II trial were to evaluate the efficacy and safety of cetuximab maintenance therapy following definitive RT with concomitant cetuximab in pts with locally advanced oropharyngeal cancer. Methods: Main eligibility criteria: >18 yrs old, stage III-IVM0 squamous tumors. Group A received concomitant boost RT (69.9Gy in 28 days) + cetuximab (400 mg/m2 1 wk before RT and 250 mg/m2/wk during RT). Group B received an additional 12 consecutive wks of cetuximab maintenance therapy. The primary endpoint was locoregional control (LRC) at 1 yr, secondary endpoints included LRC-2yrs, event-free survival, overall survival, safety and a molecular analysis (reported at meeting). Results: Demographics of the 91 enrolled pts (45 [A]; 46 [B]) were (A/B): median age (range), 60(42-75)/61(45-80); males, 80%/91%; Stage IV, 73%/72%, KPS>80, 67%/72%. Safety and compliance were previously reported (ASCO/08): cetuximab was well tolerated during and after RT. In group B, compliance in the maintenance phase was high, but 4 pts did not receive cetuximab as maintenance therapy (2 consent withdrawals and 2 AEs). 3 pts in group A and 2 in group B died within 12 wks after the last RT treatment; none was related to study treatment but occurred in the context of disease complications or underlying disease. Complete responses at 12 wks (A/B): 55.6%/69.6%; posterior cervical neck dissection: 13.3%/8.7%. Median follow-up of 26.5 mths. Efficacy parameters at 1 yr (A/B): LRC: 56.8%/60.5%, event-free survival 55.6%/60.9% and overall survival 75.6%/87%. Total deaths (cut-off July/09): 21(46.6%)/20(43.5%); 14(31.1%)/12(26.1%) due to disease progression. There were 8 (3 vs. 5) secondary tumors, mainly lung cancer. Conclusions: Twelve weeks of cetuximab maintenance therapy after concomitant cetuximab + RT in locally advanced oropharyngeal carcinoma, is feasible and may improve clinical outcomes measured at 1 year. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Merck Serono Merck Serono, Merck Merck Serono