Clinical experience with HLA-B7 plasmid DNA/lipid complex in advanced squamous cell carcinoma of the head and neck

Objective: To investigate the safety and efficacy of alloantigen plasmid DNA therapy in patients with advanced head and neck squamous cell carcinoma using Allovectin-7 (Vical Inc, San Diego, Calif), a DNA/lipid complex designed to express the class I major histocompatibility complex antigen HLA-B7. Design: Multi-institutional prospective trial. Setting: Academic medical setting. Patients: A total of 69 patients were enrolled in 3 sequential clinical trials: a single-center phase 1 trial and 2 multicenter phase 2 trials. Eligibility criteria included unresectable squamous cell carcinoma that failed conventional therapy, Karnofsky performance status score of 70 or greater, and no concurrent anticancer or immunosuppressive therapies. Intervention: Patients received 2 biweekly intratumoral injections of 10 μg (phase 1 and first phase 2 trials) or 100 μg (second phase 2 trial) of Allovectin-7 followed by 4 weeks of observation. Patients with stable or responding disease after the observation period were given a second treatment cycle identical to the first. Main Outcome Measures: Patients were assessed for toxic effects, and tumor size was measured after cycles 1 (at 6 weeks) and 2 (at 16 weeks). Results: Allovectin-7 treatment was well tolerated, with no grade 3 or 4 drug-related toxic effects. Of 69 patients treated, 23 (33%) had stable disease or a partial response after the first cycle of treatment and proceeded to the second cycle. After the second cycle, 6 patients had stable disease, 4 had a partial response, and 1 had a complete response. Responses persisted for 21 to 106 weeks. Conclusions: Intratumoral plasmid DNA immunotherapy for head and neck cancer with Allovectin-7 is safe, and further investigations are planned in patients with less advanced disease, where it could potentially improve patient survival and reduce the need for radical high-morbidity treatments.