Near-Infrared Photoimmunotherapy for Oropharyngeal Cancer

SIMPLE SUMMARY: Near-infrared photoimmunotherapy (NIR-PIT) represents a potential novel treatment modality for a range of cancer types, including head and neck cancers. NIR-PIT is based on the conjugation of photoactivating chemicals to cancer cell-specific antibodies. Antibody-photoabsorber-conjugate causes killing of cancer cells when activated by near-infrared light. NIR-PIT is considered to have particularly promising applications in head and neck cancers and these tumors are typically more easily accessed for illumination. Two patients with oropharyngeal lesions treated with NIR-PIT at our institution had good response with no serious adverse events and no functional disorders. ABSTRACT: Human papillomavirus (HPV)-associated oropharyngeal cancer has a better prognosis than other head and neck cancers. However, rates of recurrence and metastasis are similar and the prognosis of recurrent or metastatic HPV-associated oropharyngeal cancer is poor. Near-infrared photoimmunotherapy (NIR-PIT) is a treatment involving administration of a photosensitizer (IRDye(®)700DX) conjugated to a monoclonal antibody followed by activation with near-infrared light illumination. It is a highly tumor-specific therapy with minimal toxicity in normal tissues. Moreover, NIR-PIT is expected to have not only direct effects on a treated lesion but also immune responses on untreated distant lesions. NIR-PIT with cetuximab-IR700 (AlluminoxTM) has been in routine clinical use since January 2021 for unresectable locally advanced or locally recurrent head and neck cancer in patients that have previously undergone radiotherapy in Japan. NIR-PIT for head and neck cancer (HN-PIT) is expected to provide a curative treatment option for the locoregional recurrent or metastatic disease after radiotherapy and surgery. This article reviews the mechanism underlying the effect of NIR-PIT and recent clinical trials of NIR-PIT for head and neck cancers, treatment-specific adverse events, combination treatment with immune checkpoint inhibitors, illumination approach and posttreatment quality of life, and provides a case of series of two patients who receive NIR-PIT for oropharyngeal cancer at our institution.