A Study of ASP-1929 Photoimmunotherapy in Combination With Pembrolizumab in First-line Treatment of Locoregional Recurrent Squamous Cell Carcinoma of the Head and Neck With No Distant Metastases

The goal of this clinical trial is to learn if ASP-1929 photoimmunotherapy (PIT) in combination with pembrolizumab works to treat recurrent squamous cell cancer of the head and neck (HNSCC) with no distant metastases. It will also learn about the safety of ASP-1929 PIT in combination with pembrolizumab. Researchers will compare ASP-1929 PIT in combination with pembrolizumab to pembrolizumab alone or pembrolizumab plus chemotherapy (carboplatin or cisplatin, plus 5-fluorouracil or paclitaxel or docetaxel) according to physician's choice (control arm). The overall primary study hypothesis being tested is whether ASP-1929 PIT plus pembrolizumab combination treatment improves the overall survival (OS) of the population defined by the inclusion/exclusion criteria over the control arm.