HPV 16-positive and/or HPV 18-positive Recurrent and/or For Patients With Metastatic Head and Neck Cancer to Evaluate GX-188E DNA Vaccination, GX-I7 and Nivolumab Combination Therapy

"* Nivolumab 3 mg/kg IV administered every 2 weeks~* GX-188E 2 mg IM at Weeks 1, 2, 4, 7, 10, 13, and 19~* GX-I7 1200 μg/kg or the recommended dose of the introductory safety cohort is administered at weeks 2, 10, and 18"