BigHat Biosciences closed a $75 million Series C on September 24, 2026, giving the San Mateo AI-drug developer $223 million in total funding and the resources to push its first clinical candidate — an antibody-drug conjugate for gastric cancer — through Phase 1. The round was co-led by crossover investor DFJ Growth and Premji Invest, and puts BigHat in the small group of AI-first biotechs already dosing patients.
The Round
Alongside DFJ Growth and Premji Invest, the syndicate includes Catalio Capital Management, LG Technology Ventures and Sigmas Group as new investors, with follow-on checks from 8VC, Alexandria Venture Investments, Amgen Ventures, Andreessen Horowitz, Discovery Ventures, GRIDS Capital, Intermountain Ventures, Eli Lilly and Company, Merck Global Health Innovation Fund, Quadrille Capital and Section 32. It is the largest single round in BigHat's seven-year history and follows the company's move from asset creator to clinical-stage operator.
Milner And BHB810
BigHat argues that its edge is neither the pipeline nor the models but the wet-lab loop that connects them. The Milner platform pairs large biological models with high-throughput automated experimentation, generating BigHat's own training corpora rather than relying on public antibody databases. That workflow produced BHB810, a CDH17-directed antibody-drug conjugate that just dosed its first patient. A second program, BHB299 — an avidity-driven T-cell engager — is on track for human trials in 2027.
Where It Sits In The AI-Drug Race
Investor appetite for AI-designed therapeutics has re-heated dramatically in 2026, with Enveda's $311M Series E, Basecamp Research's $140M Series C and Novo Nordisk's Anthropic partnership all closing in the past two weeks. What differentiates BigHat's pitch is that it is one of the very few AI drug-discovery companies with an internal molecule already in the clinic, rather than a platform sold to Big Pharma.
Peyton Greenside
"This round lets us bring our first program through Phase 1 while accelerating the rest of our pipeline," CEO and co-founder Peyton Greenside said in the announcement. BigHat's original bet — that owning the wet-lab data loop would matter more than owning the biggest model — is now being tested at the clinical trial stage.
Reporting based on coverage from BioSpace, Axios Pro Biotech Deals and Business Wire.