Inovio Pharmaceuticals, Inc. announced that a second patient with HPV-related head and neck cancer treated with INO-3112 (now called MEDI0457) in a Phase 1 trial achieved a sustained complete response (full remission) after subsequent treatment with a PD-1 checkpoint inhibitor. This marks the second patient with metastatic cancer observed in full remission (complete response) after treatment with synthetic DNA vaccine followed by a PD-1 checkpoint inhibitor. Both patients who achieved full cancer remission were treated with four doses of synthetic DNA vaccine as part of a Phase 1 monotherapy trial of 22 patients with HPV related head and neck squamous cell carcinoma in which 91% of patients (20/22) showed T cell activity in the blood or tissue. This demonstrates that synthetic DNA vaccine generated robust HPV16/18 specific CD8+ T cell responses in peripheral blood and increased CD8+ T cell infiltration in resected tumor tissue samples. Of the four patients who developed progressive disease and were subsequently administered a PD-1 checkpoint inhibitor, two patients rapidly exhibited a complete response. The most recent patient for which data was presented, received pembrolizumab (KEYTRUDA®); while the previously reported complete responder was treated with nivolumab (OPDIVO®). The patients moved from metastatic head and neck cancer to no evidence of disease and they remain alive two years after treatment. Detailed results of the first patient with head and neck cancer who received nivolumab were published in the October issue of Clinical Cancer Research.