Efficacy and safety of CetuGEX in recurrent/metastatic squamous cell carcinoma of the head and neck (RM-HNSCC): Results from the randomized phase II RESGEX study.

59Background: Standard treatment for RM-HNSCC is a combination of cisplatin (P), 5-FU (F), and the epidermal growth factor receptor (EGFR) blocking monoclonal antibody cetuximab. CetuGEX is a new monoclonal antibody sharing the identical EGFR-binding domain with cetuximab, but a modified Fc part by a proprietary glycosylation method to optimize antibody dependent cellular cytotoxicity (ADCC). Methods: Patients with RM-HNSCC without relevant comorbidities were randomized to receive up to 6 cycles of P 100 mg/m2, F 4 x 1000 mg/m2/24hrs and CetuGEX vs. cetuximab. Initial dose of cetuximab was 400mg/m2, followed by weekly 250 mg/m2. CetuGEX was given as 990 mg, followed by weekly 720 mg. After end of combination treatment, patients received single agent antibody maintenance until disease progression or intolerable toxicity. Stratification factors included FcγRIIIa status, primary tumor site, EGFR pretreatment vs. naive, and recurrent vs. metastatic disease. Primary endpoint was progression-free survival (PFS)...