6065 Background: Treatment for patients with platinum-refractory metastatic squamous cell carcinoma of the head and neck (SCCHN) is limited. Cetuximab has been approved in the US in this patient population based on a phase II trial that demonstrated 13% response rate (RR) and 5.9 months median OS. A recently conducted phase III trial of zalutumumab, a human monoclonal IgG1k antibody against EGFR, versus best supportive care showed significant increase in PFS. Here, we present the results of a companion phase II trial in the same patient population. Methods: Patients with platinum-refractory recurrent or metastatic SCCHN received weekly infusions of zalutumumab starting at a loading dose of 8mg/kg. The dose was then reduced to 4mg/kg and individually titrated by increments of 4mg/kg every 2 weeks based on skin rash evaluation up to a maximum of 16mg/kg aiming at a grade 2 skin rash. Primary objective was OS. The analysis was based on the intent-to-treat principle and OS was estimated using the Kaplan-Meier method. Results: Between January 2008 till August 2011 90 patients were enrolled in 57 centers in the United States, Europe and South America. 23% of patients had WHO PS 2 and 74% had distant relapse metastases. Grade 3-4 adverse events (AEs) related to zalutumumab were observed in 19% of the patients and included skin rash (5%), hypomagnesemia (4%) and pneumonitis (1%). Infusion-related reactions occurred in 33% of patients. The frequency of all-cause grade 3-4 AEs was 62% and included infections (14%), gastrointestinal disorders (12%), hypokalemia (6%), dyspnea (9%) and anemia (6%). Two deaths secondary to cardiac arrest in a patient with history of myocardial infarction, and respiratory acidosis in a patient with a pleural effusion and hypomagnesemia were deemed related to zalutumumab. CR was observed in one (1%) patient and PR in four (5%) patients. The median PFS was 8.6 weeks (95% CI [8.0, 10.4]) and the estimated median OS was 5.3 months (95% CI [4.1, 7.1]). Conclusions: Zalutumumab showed reasonable efficacy in platinum-refractory recurrent or metastatic SCCHN patients and dosing titration based on skin rash evaluation was feasible. Clinical trial information: NCT00542308.