Topos Bio

About Topos Bio

Topos Bio is an AI-powered biotechnology company headquartered in San Francisco that is developing a drug discovery platform for intrinsically disordered proteins (IDPs), which are implicated in diseases like Alzheimer's, Parkinson's, and various cancers. The company emerged from stealth in January 2026 with $10.5 million in seed funding. The round was led by Boldstart, Threshold, and Neo, with participation from angel investors such as Uber CEO Dara Khosrowshahi and Unconventional AI CEO Naveen Rao.

The company was founded by researchers from UC Berkeley and Stanford. CEO Ryan Zarcone, who previously led AI at Fountain Therapeutics and trained as a biophysicist at UC Berkeley's Redwood Center for Theoretical Neuroscience, co-founded the company with Amir Khosrowshahi, former CTO of Intel AI and co-founder of Nervana, which was acquired by Intel. The team combines expertise in physics, artificial intelligence, and neuroscience to address the challenges of targeting IDPs.

Traditional drug discovery follows a "lock-and-key" model, which is ineffective for IDPs because they lack a fixed 3D shape and instead rapidly fluctuate between many conformations. This has made approximately one-third of the human proteome "undruggable" by conventional methods. Topos Bio's platform models the dynamic ensembles of these proteins rather than static structures, allowing it to identify transient binding opportunities. The company's foundation model, Topos-1, is designed to generate these conformational ensembles and has demonstrated improved performance compared to existing models like AlphaFold in internal benchmarks. This computational approach is integrated with an in-house wet lab for experimental validation, creating a continuous feedback loop to refine the AI models.

Topos Bio's business model focuses on rationally designing small molecules, peptides, and targeted protein degraders against these previously inaccessible targets. The company's initial discovery programs are centered on neurodegenerative diseases, with plans to expand into oncology and metabolic disorders. As part of its strategy, Topos Bio has entered a collaboration with Gladstone Institutes to discover novel modulators for alpha-synuclein, a disordered protein associated with Parkinson's disease, validating its platform on established disease models.