Chai Discovery, a biotech startup supported by OpenAI, revealed a $130 million Series B funding round on Monday, valuing the company at $1.3 billion. The investment was spearheaded by General Catalyst and Oak HC/FT.

Additional participants in the round include Menlo Ventures, OpenAI, Dimension, Thrive Capital, Neo, Yosemite venture fund, Lachy Groom, SV Angel, and new backers Glade Brook and Emerson Collective. This latest infusion brings the firm's total funding to over $225 million.

The company operates within a rapidly expanding sector that views artificial intelligence as a means to accelerate drug development. In August, Menlo Ventures led Chai's $70 million Series A round, describing the startup as focused on building foundation models specifically tailored for drug discovery. These models aim to predict interactions between biochemical molecules, enabling them to be reprogrammed for therapeutic purposes.

Chai states its goal is to create the "computer aided design suite" for molecules. Last year, the startup introduced the Chai 1 AI model and is now rolling out its latest iteration, Chai 2.

The company reports that Chai 2 is delivering substantial improvements in success rates for de novo antibody design—a process that involves constructing custom antibodies from the ground up rather than modifying existing ones. "Our latest models can design molecules that have properties we’d want from actual drugs, and tackle challenging targets that have been out of reach," said Josh Meier, Chai’s co-founder and CEO, in a prepared statement.

According to his LinkedIn profile, Meier has a background in machine learning and previously held research and engineering roles at Facebook. Prior to that, he worked at OpenAI. Chai Discovery was founded in 2024.