Stephen M. Ansell

Stephen M. Ansell, MD, PhD is Professor of Medicine, Division Chair of Hematology, and co-leader of the Lymphoma Program at Mayo Clinic. He is internationally recognized as a pioneer in elucidating the role of PD-1 checkpoint blockade in Hodgkin lymphoma and is one of the principal investigators of the CheckMate 205 trial — a phase II study demonstrating remarkable activity of nivolumab (anti-PD-1) in relapsed/refractory classical Hodgkin lymphoma that led to accelerated FDA approval of nivolumab in this disease. Crucially, Dr. Ansell's laboratory made the seminal discovery that the 9p24.1 chromosomal amplification — nearly universal in classical Hodgkin lymphoma — drives transcriptional upregulation of PD-L1 and PD-L2 on Reed-Sternberg cells, providing the molecular rationale for why Hodgkin lymphoma is exquisitely sensitive to PD-1 blockade. This work mechanistically linked tumor genomics to exceptional immunotherapy sensitivity and has been cited as a paradigm for identifying immunotherapy-responsive tumor types. Dr. Ansell has also led translational research on the Hodgkin lymphoma tumor microenvironment, characterizing the complex network of immunosuppressive cells (Tregs, M2 macrophages, exhausted T cells) that protect Reed-Sternberg cells, and has contributed to numerous other lymphoma clinical trials including bispecific antibodies and NK cell-based therapies.