Chai Discovery Announces $70 million Series A To Transform Molecular Design

SAN FRANCISCO--(BUSINESS WIRE)--Chai Discovery, the AI company that predicts and reprograms the interactions between biochemical molecules to accelerate life-changing therapeutics, today announced its $70 million Series A financing round.

The fundraise was led by Menlo Ventures, including investment from their Anthology Fund, a joint partnership with Anthropic to identify and back promising AI companies, with participation from new investors Yosemite, DST Global Partners, SV Angel, Avenir, DCVC, and others. It also included existing investors Thrive Capital, OpenAI, Dimension, Neo, Lachy Groom, and Fred Ehrsam, among others.

“Progress towards game-changing drugs and treatments is far too slow, stymied by costly trial-and-error experiments,” said Joshua Meier, CEO and co-founder. “Chai Discovery exists to push the boundaries of what's possible in this field, applying frontier AI to transform biology from science to engineering, so that breakthroughs can be designed rather than simply discovered.”

Chai was founded in 2024 by Joshua Meier (ex AI drug discovery firm Absci; Facebook AI; OpenAI), Jack Dent (ex Eng and Product leader at Stripe), and AI researchers Matthew McPartlon and Jacques Boitreaud.

Mikael Dolsten M.D., PhD., the former Pfizer Chief Scientific Officer responsible for advancing 150 molecules into clinical trials and delivering 36 approved medicines, is joining the company’s board of directors.

“I’m proud to join Chai Discovery and redefine biology from science into engineering,” Dr. Dolsten said. “This is going to be an incredible journey with an incredible team.”

Last year, the company closed a $30 million seed round led by Thrive Capital, OpenAI, and Dimension. Soon after, they released Chai-1, an open-source foundation model for molecular structure prediction that performs at the state-of-the-art

Last month, the team unveiled a further leap in AI-driven drug discovery with their Chai‑2 breakthrough, delivering fully de novo antibody design with a near-20% hit rate. By contrast, traditional lab based methods often have to screen millions to billions of antibodies to find hits, and the previous state of the art for computational methods was only 0.1%.

When inputting only the target antigen and epitope, Chai‑2 can generate successful binders from scratch against a wide variety of targets. This means that scientists working on a target antigen, a specific disease-causing protein such as a virus or type of cancer, can use Chai-2 to design, from scratch, completely new antibodies that can hit the right spot.

“Before Chai-2, the process was not unlike searching a giant bunch of keys for the right fit for a lock—but there are millions of keys,” said Matthew McPartlon, co-founder. “Now, it’s like having a master locksmith design exactly the right shape key, based only on your description of the lock. A company had spent more than three years and over $5m on a problem. With Chai-2, we were able to find an experimentally validated solution within two weeks.“

The funding will be used to further develop the Chai platform, applying it toward previously inaccessible targets, and onboarding select partners.

“Chai is an exceptional technical team building foundation models for biology to transform drug discovery,“ said Greg Yap, Partner at Menlo Ventures. “Chai-2 demonstrates amazing progress in antibody design, and we have seen a meaningful fraction of the biotech industry already apply for Chai-2 access. At Menlo, we invest deeply in both AI foundation models and technology-enabled biology–we believe Chai can help create better medicines faster.”

For more information on Chai Discovery and its platform, visit https://www.chaidiscovery.com.

About Chai Discovery

Chai Discovery builds frontier artificial intelligence to predict and reprogram the interactions between biochemical molecules, the fundamental building blocks of life. Its mission is to transform biology from science into engineering. The team hails from pioneering research and applied AI companies such as OpenAI, Meta FAIR, Stripe, and Google X, and is backed by top investors including OpenAI, Thrive Capital, Menlo Ventures and Dimension.