Equipped with the training of a medical doctor and the curiosity of a laboratory scientist, Hugh Rosen, MD, PhD, embarked on a 25-year quest to transform the lives of people with multiple sclerosis. In early 2020 that mission was accomplished: ozanimod, a drug invented by Rosen and fellow Scripps Research professor Edward Roberts, PhD, received approval from the FDA to treat relapsing forms of multiple sclerosis. Additionally, ozanimod’s ability to dampen the effects of the immune system holds promise for treating other autoimmune conditions, including ulcerative colitis and Crohn’s disease. Ozanimod, marketed as Zeposia, is taken as a once-daily pill.