‘ChatGPT for Doctors’ OpenEvidence Raises $250M, Quietly Pivots Into Drug Development

The market for AI-powered clinical search is heating up. Publicly traded Doximity told investors its AI Scribe user base nearly tripled in a single quarter, while Abridge took a strategic equity investment from Eli Lilly and is expanding into clinical-trial patient recruitment. Even OpenEvidence, the company that built the “ChatGPT for doctors” category, isn’t immune to that pressure.

OpenEvidence raised another $250 million, Forbes reported. The company itself never put out a press release. What stands out is how quietly it landed: unlike January’s Series D — a $12 billion valuation announced with a CNBC appearance for the CEO — this one surfaced as a single sentence buried inside a Forbes story about a hospital partnership.

CEO Daniel Nadler told Forbes that OpenEvidence is moving into developing its own cancer drugs, with a first candidate entering clinical trials before year-end and three to five more next year, starting with rare cancers. Rather than go head-to-head with Eli Lilly or Pfizer on large trials, Nadler said the company is targeting “the stuff that they are not doing, and maybe can’t do” — the bet being that reaching most of America’s physicians makes it far easier to find the handful of patients a rare-disease trial needs.

The partnership announced the same day is the first building block. MSK and OpenEvidence said they’re integrating OpenEvidence into MSK’s Epic electronic health record system, while OpenEvidence brings MSK’s OncoKB precision-oncology database onto its own platform for physicians outside MSK. OncoKB became the first, and remains the only, somatic cancer variant knowledge base partially recognized by the FDA, in 2021.

The new model family OpenEvidence unveiled earlier this month points the same direction. The company said its Darwin model became the first AI in history to score a perfect mark on MedQA, the leading independent medical AI benchmark. Because Darwin can reason at the frontier of virology, immunology, and genetics, OpenEvidence is keeping it gated to approved institutional partners — and one of its first is the National Organization for Rare Disorders, a choice that lines up directly with the drug-development push.

Nadler holds a physics PhD from Harvard and sold his previous company, financial-data firm Kensho, to S&P Global in 2018 before founding OpenEvidence in 2022.

The company’s valuation has climbed fast: a $3.5 billion Series B in July 2025, a $6 billion Series C that October, and a $12 billion Series D in January co-led by Thrive Capital and DST Global — making this its fifth round. Per Forbes, this one was led by Byers Capital, the family office founded by Blake Byers, and Andreessen Horowitz, at a reported $15 billion valuation — up 25% from January.

That said, The Information reported in July that OpenEvidence had explored raising $200 million at a $20 billion valuation but didn’t move forward. Measured against that earlier number, this round lands lower — and combined with the quiet rollout, some in the industry read it as a down round in disguise. The generous read is that Nadler sees a rare-disease recruiting edge no rival can match. The less generous one is that ad-supported clinical search was hitting a ceiling, and drug development made for a better story to sell.

Competitive pressure is coming from two directions. One is Big Tech moving directly into OpenEvidence’s own category — AI-powered clinical search and decision support. Anthropic launched Claude for Healthcare at the J.P. Morgan Healthcare Conference in January, offering hospitals, payers, and pharma companies HIPAA-ready infrastructure wired directly into the CMS coverage database, ICD-10 codes, and PubMed. OpenAI is chasing the consumer side with ChatGPT Health, linking personal health records scattered across Apple Health, Epic, and Oracle Health, plus EHR data from roughly 2.2 million U.S. providers, so patients can make sense of their own health data.

The other is specialist startups expanding in from an adjacent category — clinical documentation. Publicly traded Doximity posted quarterly revenue up 23% year-over-year to $169 million. Abridge’s valuation jumped to $5.3 billion, and its Eli Lilly tie-up lets it surface trial-eligible patients from within clinical conversations and feed them into Lilly’s pipeline — partnering with a drugmaker to recruit for trials, rather than becoming one itself.