Therapeutic Host Anticancer Immune Response through Photoimmunotherapy for Head and Neck Cancer May Overcome Resistance to Immune Checkpoint Inhibitors
Satoshi Koyama, Hiroaki Ehara, Ryohei Donishi, Kenkichiro Taira, Takahiro Fukuhara, Kazunori Fujiwara
Abstract
Introduction: Near-infrared photoimmunotherapy (NIR-PIT) is a recently developed hybrid cancer therapy that directly kills cancer cells while producing a therapeutic host anticancer immune response. The activation of host immunity using NIR-PIT can enhance the effects of immune checkpoint inhibitors (ICIs) in animal experimental models; however, there have been no reports of this phenomenon in humans. Furthermore, by activating host immunity using NIR-PIT in patients who have become resistant to ICIs, the effects of ICIs can be restored. Case Presentation: A 56-year-old male experienced local recurrence after chemoradiotherapy for maxillary sinus cancer (cT4bN0M0). The disease had progressed following ICI antiPD-1 antibody therapy. He underwent NIR-PIT for four cycles; however, a local recurrent tumor remained and began a rapid regrowth. The ICI antiPD-1 antibody was then readministered following NIR-PIT. As a result, sensitivity to antiPD-1 therapy was restored, and the tumor shrank. Finally, a complete response was observed without major adverse events associated with subsequent antiPD-1 antibody treatment following NIR-PIT. Conclusion: These results indicated that NIR-PIT may not only activate host anticancer immunity but also enhance the effects of ICIs and overcome antiPD-1 resistance.