Today, we’re thrilled to co-lead Chai Discovery’s $130 million Series B to support Chai’s mission to transform biology into an engineering discipline capable of tackling medicine’s hardest problems.

Josh Meier, Jack Dent, Matt McPartlon, and Jacques Boitreaud’s partnership was a decade in the making. Over joint AI research at Harvard, Josh and Jack forged a friendship and discovered a shared instinct for tackling problems with rigor and curiosity.

Josh helped pioneer frontier AI in the early days of OpenAI and at Meta where he co-led development of ESM1, the first transformer protein-language model. After Meta, Josh and Matt led the AI division at Absci, where they pioneered early research on de novo antibody design and contributed to multiple drugs now in the clinic. 

During this time, Jacques led AI at Aqemia, productionizing ML tools for small molecule discovery, while Jack honed his craft building resilient, large-scale machine-learning systems at Stripe. 

Spurred by a shared view that profound technological shifts have the potential to transform drug discovery, the four founders came together to build Chai Discovery.  

From Serendipity to Design

Almost four decades after the first monoclonal antibody was approved, the impact of biologics on medicine cannot be overstated. Life-changing medicines like Humira and Keytruda (both monoclonal antibodies) for autoimmune diseases and cancer are available because of the Nobel Prize-winning work of Frances Arnold, George P. Smith, Gregory Winter, and other pioneers. 

Today, we believe we are at the beginning of a new era of drug discovery. Recently, Chai Discovery announced that their model, Chai-2, can design full-length monoclonal antibodies with developability comparable to approved therapeutics. Over 85% of hits proposed by the model met this criteria for thermostability, polyreactivity, self-interaction, hydrophobicity, expression, purity, aggregation, and humanness. Achieving drug-like properties using computational methods with high success rates is, as far as we know, unprecedented.

Perhaps even more importantly, Chai has also demonstrated that their models can tackle targets that were traditionally considered “hard to drug” or “undruggable.” We believe that the generation of functional GPCR agonists with minimal screening and the ability to discriminate single-residue peptide MHC mutations by Chai-2 marks a critical step toward a future in which Chai’s platform consistently designs medicines against currently intractable targets. 

We're excited to partner with Josh, Jack, Matt, Jacques, and the entire Chai Discovery team as they accelerate the development of novel medicines to advance human health.