Its lead candidate, zelquistinel, is in Phase II trials for major depressive disorder as of Q2 2025, with plans to expand into Alzheimer’s disease. The pipeline also includes early-stage programs for schizophrenia and other synaptopathies.

The company launched with over $90 million in funding from Catalio Capital Management, Innoviva, Tenmile, Luson Bioventures, Palo Santo, and strategic investors AbbVie and Lilly.

Syndeio is led by Co-founder and CEO Derek Small, with scientific guidance from Nobel Laureate Thomas Südhof as Co-chair of the Scientific Advisory Board. The team brings a targeted focus on synapse biology to address the root causes of neurological and psychiatric conditions.