— Phase 2b closely resembles PAX-D study design, which demonstrated an effect size for pramipexole more than two times larger than approved TRD therapies — — Trial design and MADRS primary endpoint aligned with FDA standards in depression, potentially supporting a single Phase 3 registrational pathway — — Prior Phase 2a demonstrated robust antidepressant effects of ALTO-207 and favorable tolerability — — Topline data expected in 2H 2027 — Alto Neuroscience, Inc. (NYSE: ANRO), a clinical-stage biopharmaceutical company focused on precision medicines for neuropsychiatric disorders, today announced the initiation of a Phase 2b randomized, placebo-controlled trial of ALTO-207 in treatment-resistant depression (TRD), a program designed to replicate the strongly positive PAX-D study results and support a streamlined path to registration. TRD is estimated to affect up to 7 million adults in the United States, representing patients who do not respond adequately to current antidepressant therapies.