A Study of HB-202/HB-201 With Pembrolizumab in Patients With HPV16+ Recurrent/Metastatic Oropharyngeal Cancer

This is a study of HB-202/HB-201 alternating 2-vector therapy with pembrolizumab (also known as Keytruda®) in people with human papillomavirus subtype 16 positive (HPV16+) head and neck cancer starting in the middle part of the throat, who have not yet received systemic treatment after their cancer spread (metastatic) and/or returned (recurrent) and who are eligible to receive pembrolizumab. Doctors already use pembrolizumab therapy (with or without chemotherapy) to treat head and neck cancer. However, the treatment does not work well in most people with this type of cancer. HB-202/HB-201 alternating 2-vector therapy with pembrolizumab, which is designated to stimulate a stronger immune attack against HPV16+ tumors, was shown to be safe and suggested to work better than pembrolizumab-only in a small number of participants with HPV16+ head and neck cancer (see H-200-001, NCT04180215). This trial studies HB-202/HB-201 alternating 2-vector therapy with pembrolizumab in a much larger number of participants from different countries to confirm its benefits for people with HPV16+ head and neck cancer that started in the middle part of the throat compared with pembrolizumab-only therapy. This trial studies whether administering HB-202/HB-201 alternating 2-vector therapy with pembrolizumab works better in more participants by shrinking their tumors and makes them live longer than pembrolizumab-only therapy. Participants will receive the study treatments by injection into a vein every 3 weeks during the first 3 months and then every 6 weeks until up to about 2 years, which will be followed by a long observation period to continue looking at the safety and clinical benefits after the last dose of study treatment.