When the first chimeric antigen receptor T-cell (CAR T) therapy, Kymriah (tisagenlecleucel), was approved in 2016 for treating B-cell acute lymphoblastic leukemia, its developer, Novartis AG, confined the initial rollout to just 20 treating centers. Its label carried a black box warning, because of the risk of life-threatening cytokine release syndrome, and Basel, Switzerland-based Novartis put in place a comprehensive risk evaluation and mitigation system to ensure its safe use. Catamaran Bio Inc., a Boston-based startup that has raised $42 million in seed and series A financing, is considering the administration of similarly engineered natural killer cells in walk-in clinics. “If the product is safe, it can be given as an out-patient treatment,” Chief Scientific Officer Vipin Suri told BioWorld. “As a field, this absolutely has to be our ambition.”