Chai Discovery announced a $70 million Series A financing round to advance its artificial intelligence platform that predicts and reprograms molecular interactions for therapeutic development. The Menlo Ventures-led round, which includes investment from their Anthology Fund partnership with Anthropic, brings the company's total funding to $100 million since its 2024 founding.
The funding follows the company's breakthrough with Chai-2, a foundation model that achieves fully de novo antibody design with a near-20% hit rate. This represents a dramatic improvement over traditional laboratory-based methods, which often require screening millions to billions of antibodies to identify hits, and previous computational approaches that achieved only 0.1% success rates.
Revolutionary Antibody Design Capabilities
Chai-2 can generate successful antibody binders from scratch when provided only with target antigen and epitope information. The platform works across a wide variety of targets, enabling scientists to design completely new antibodies against specific disease-causing proteins such as viruses or cancer-related targets.
"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," explained 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."
The platform's efficiency was demonstrated in a case where a company had spent more than three years and over $5 million on a problem. Using Chai-2, the team found an experimentally validated solution within two weeks.
Leadership and Strategic Vision
Former Pfizer Chief Scientific Officer Mikael Dolsten, M.D., Ph.D., joined Chai Discovery's board of directors. During his tenure at Pfizer, Dolsten was responsible for advancing 150 molecules into clinical trials and delivering 36 approved medicines.
"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."
CEO and co-founder Joshua Meier, who previously worked at AI drug discovery firm Absci, Facebook AI, and OpenAI, emphasized the company's mission to accelerate therapeutic development. "Progress towards game-changing drugs and treatments is far too slow, stymied by costly trial-and-error experiments," Meier said. "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."
Technology Platform and Previous Achievements
The company previously released Chai-1, an open-source foundation model for molecular structure prediction that performs at state-of-the-art levels. This followed a $30 million seed round led by Thrive Capital, OpenAI, and Dimension.
The Series A round included participation from new investors Yosemite, DST Global Partners, SV Angel, Avenir, and DCVC, along with existing investors Thrive Capital, OpenAI, Dimension, Neo, Lachy Groom, and Fred Ehrsam.
Industry Impact and Future Applications
Greg Yap, Partner at Menlo Ventures, noted significant industry interest in the platform. "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," Yap said. "At Menlo, we invest deeply in both AI foundation models and technology-enabled biology—we believe Chai can help create better medicines faster."
The funding will support further development of the Chai platform, with applications toward previously inaccessible targets and onboarding of select partners. The company's team includes researchers from OpenAI, Meta FAIR, Stripe, and Google X, bringing together expertise in artificial intelligence and molecular biology.
