ASP-1929 Photoimmunotherapy (PIT) Study in Patients With Recurrent Head/Neck Cancer

Inclusion Criteria: * Provide written informed consent. * Male or female ≥ 18 years of age at the time of informed consent * Documentation of histologically confirmed, resectable (by standard of care surgery), primary or recurrent locoregional HNSCC or cuSCC. Note: For patients with HNSCC, tumor locations must be in the oropharynx, oral cavity, sinonasal tract, hypopharynx, or larynx. Patients may not have a primary tumor site of nasopharynx (any histology). * At least one tumor lesion accessible for ASP-1929 PIT illumination that is also amenable to imaging with the Fluorescence Imaging System camera (must be within 0.5 cm and no more than 3 cm depth to the skin or mucosal surface, with the longest diameter less than 5 cm as judged by pre-treatment imaging or examination) and radiographically measurable by RECIST 1.1, as assessed by the Investigator. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1 at the time of screening. * Adequate organ function laboratory values (all screening labs should be performed ≤ 14 days of Day 1) * Female patients of childbearing potential must not be pregnant (confirmed by negative pregnancy test \[urine or serum\] at screening), not breastfeeding and must be willing to use a method of highly effective birth control, or practice abstinence throughout the study and for 60 days after the last dose of ASP-1929. * Male patients must be sterile or agree to use an adequate method of contraception or practice abstinence thro…