Tasuku Honjo

Tasuku Honjo discovered PD-1 (programmed death-1) in 1992 and subsequently demonstrated its role as an immune checkpoint receptor whose engagement by PD-L1 on tumor cells suppresses anti-tumor T cell immunity, a discovery recognized with the 2018 Nobel Prize in Physiology or Medicine. His work directly enabled the development of nivolumab, pembrolizumab, and the entire class of PD-1/PD-L1 checkpoint inhibitors that have become the backbone of modern cancer immunotherapy across dozens of tumor types. PD-1 blockade has achieved durable responses in melanoma, lung cancer, renal cell carcinoma, bladder cancer, and many other malignancies. His discovery of PD-1 is one of the most consequential advances in the history of cancer medicine.