OpenAI Backed Chai Discovery Partners With Eli Lilly to Accelerate Biologics Discovery

Chai Discovery, an AI startup founded in 2024, has gone from concept to reaching unicorn status in just 18 months. The San Francisco-based startup has raised close to $230 million, reached a $1.3 billion valuation, and secured a high-profile collaboration with Eli Lilly and Company to accelerate biologics discovery using AI-driven technologies.

Announced in January 2026, the collaboration will entail Lilly to deploy Chai’s AI platform to design novel biologic therapeutics across multiple discovery targets, while the two companies develop a purpose-built AI model trained exclusively on Lilly’s proprietary data which is tailored to its internal discovery processes. This is a co-developed system embedded into Lilly’s own R&D environment, calibrated to the company’s scientific standards and operational reality.​

Drug discovery is slow and expensive, especially when it comes to biologics like antibodies. Traditional approaches like high-throughput screening rely on testing vast libraries of molecules in wet labs, a scattershot method that can take years and frequently fails to yield viable candidates.

Chai’s main technology is Chai-2, a generative design platform focused on antibodies. The company describes Chai-2 as a “computer-aided design suite” for molecules, designed to propose antibody structures that exhibit drug-like properties before they are physically synthesized. According to Chai, the system is capable of “zero-shot” antibody design and can deliver double-digit experimental hit rates, compressing parts of the discovery timeline from months to weeks by reducing the number of unsuccessful candidates that must be tested in the lab.​