Rheos

Rheos Medicines was a Cambridge, Massachusetts-based biotechnology company founded in 2018 by Third Rock Ventures with $60 million in Series A funding. The company was built around the emerging science of immunometabolism — the study of how metabolic pathways drive immune cell function and fate — to develop novel precision medicines for autoimmune and inflammatory diseases. Rheos developed a proprietary product engine that characterized the metabolic drivers of immune-mediated diseases, with initial focus on inflammatory bowel disease and related conditions. In December 2019, the company announced a major worldwide collaboration with Roche worth up to $793 million to discover new drugs in immunometabolism. Despite promising science and high-profile partnerships, Rheos shut down operations in February 2023.