Alto presented Phase 2a data for ALTO-207 at the 2026 Society of Biological Psychiatry Annual Meeting, reporting a MADRS effect size of d=1.67 at Week 6 and d=1.1 at Week 8. The Week 6 signal is notably large for treatment-resistant depression, where approved therapies typically land well below d=1.0. Alto's approach uses EEG biomarkers to pre-select patients most likely to respond; ALTO-207 is its lead asset. The larger test is the ongoing Phase 2b trial, with topline data expected in the second half of 2027.