Definium Therapeutics, Inc., a clinical stage biopharmaceutical company, develops novel products to treat brain health disorders. The company’s lead product candidates include MM120, which is in phase 3 for the treatment of generalized anxiety disorder and attention deficit hyperactivity disorder; and DT402, a R-enantiomer of 3,4-methylenedioxymethamphetamine, which is in phase 2a clinical trials for the treatment of core symptoms of autism spectrum disorder. The company was formerly known as Mind Medicine (MindMed) Inc. and changed its name to Definium Therapeutics, Inc. in January 2026. Definium Therapeutics, Inc. was founded in 2019 and is headquartered in New York, New York.