An open-label single-arm, phase II trial of zalutumumab, a human monoclonal anti-EGFR antibody, in patients with platinum-refractory squamous cell carcinoma of the head and neck

Purpose: Treatment options for patients with platinum-refractory recurrent or metastatic squamous cell carcinoma of the head and neck (R/M SCCHN) are limited. The purpose of this study was to assess the efficacy and safety of zalutumumab in platinum-refractory R/M SCCHN. Methods: Patients with platinum-refractory R/M SCCHN were enrolled if they had performance status of 0-2, age ≥18 years and adequate organ function. Patients received weekly infusions of zalutumumab individually titrated to a grade 2 skin rash. Primary objective was overall survival (OS), and secondary objectives were efficacy and safety. A subgroup analysis of OS and progression-free survival (PFS) was conducted for various demographic, disease-related and molecular factors. Results: Ninety patients were enrolled. Twenty-three percent of patients had performance status (PS) 2 and 74 % had distant metastases. Median OS was 5.3 months (95 % CI [4.1, 7.1]), and median PFS was 2.1 months (95 % CI [2.0, 2.6]). Subgroup analysis by ECOG PS revealed median OS of 6.3 months for PS = 0-1 and 2.5 months for PS = 2. Objective response rate was 5.7 %, and disease control rate was 39.8 %. Grade 3-4 adverse events related to zalutumumab were observed in 19 % of patients and included skin rash (5 %), hypomagnesemia (4 %) and pneumonitis (1 %). The frequency of all-cause grade 3-4 AEs was 62 % and included infections (14 %), gastrointestinal disorders (12 %) and hypokalemia (6 %). Two deaths were deemed related to zalutumumab [ClinicalTrials.gov Identifier: NCT00542308]. Conclusions: Zalutumumab showed reasonable efficacy in platinum-refractory R/M SCCHN patients, and dose titration based on skin rash evaluation was feasible.