Antoni Ribas

Antoni Ribas, MD, PhD is Professor of Medicine, Surgery, and Molecular and Medical Pharmacology and Director of the Tumor Immunology Program at UCLA Jonsson Comprehensive Cancer Center. He is one of the most influential figures in modern cancer immunology and melanoma treatment, internationally recognized for his foundational role in establishing pembrolizumab as a transformative therapy in melanoma and for his deep contributions to understanding the mechanisms of anti-PD-1 and anti-CTLA-4 immunity. His laboratory and clinical program at UCLA are among the world's foremost in cancer immunotherapy. Dr. Ribas was a principal investigator of the seminal KEYNOTE-001 trial, the first large-scale clinical evaluation of pembrolizumab in advanced melanoma, which demonstrated remarkable and durable response rates in patients with ipilimumab-refractory disease and in treatment-naive patients. Published in the New England Journal of Medicine and subsequent landmark reports, KEYNOTE-001 provided the pivotal evidence that led to the first FDA approval of pembrolizumab in melanoma in 2014 and launched one of the most successful immunotherapy programs in oncology history. Dr. Ribas has also made seminal contributions to understanding PD-1/PD-L1 biology, mechanisms of primary and acquired resistance to checkpoint blockade, and the role of the tumor microenvironment in determining immunotherapy outcomes. In parallel with his immunotherapy work, Dr. Ribas has led extensive research into BRAF-MEK targeted therapy combinations, including studies of adaptive resistance and the rational design of immunotherapy-targeted therapy combinations to overcome resistance. His laboratory work on T cell biology, tumor neoantigen recognition, and innate immune signaling in cancer has produced dozens of high-impact publications in Nature, Science, and Cell. He has authored more than 450 peer-reviewed publications, serves as President of AACR, and is recognized globally as an architect of modern immuno-oncology.