ALTO-207

**ALTO-207** is an investigational, modified-release fixed-dose oral combination of **pramipexole** and **ondansetron** being developed by Alto Neuroscience for treatment-resistant depression. Pramipexole is a dopamine D3-preferring D3/D2 receptor agonist intended to provide antidepressant activity through dopaminergic receptor activation. Ondansetron is a selective 5-hydroxytryptamine 3 receptor antagonist included to reduce pramipexole-associated nausea and vomiting, enabling more rapid titration and higher tolerated pramipexole doses. The program was originally developed by Chase Therapeutics as CTC-501 and was acquired by Alto Neuroscience in 2025. ALTO-207 has completed a Phase 2a study in major depressive disorder and entered a randomized, placebo-controlled Phase 2b trial in treatment-resistant depression in April 2026.

Other names

ondansetron + pramipexolepramipexole + ondansetron