Pathos AI, a clinical-stage biotech developing cancer drugs and expanding its AI platform into neurological diseases, has raised $237 million in Series E funding at a post-money valuation of around $3 billion.

NYSE-listed pharmaceutical company Bristol Myers Squibb led the round, with participation from existing investors, Pathos said Friday. The startup did not name the other participants. Earlier, Pathos investors included New Enterprise Associates, Revolution Growth, Lightbank and Builders VC.

The Series E brings Pathos' total funding to about $704 million. The startup previously raised $365 million in a Series D round at around a $1.6 billion post-money valuation in May 2025. Before that, it raised $62 million in a Series C round at a $600 million valuation in October 2024. That round took its total funding at the time to $102 million.

Pathos said it will use the new funding to expand Foundry, its AI drug development platform, and advance its four clinical-stage cancer treatments.

Foundry uses thousands of AI agents to study data about diseases, patients and clinical trials. Pathos currently lists four cancer drugs in its pipeline. Its website says these include pocenbrodib for prostate cancer and multiple myeloma, DO-2 for a type of lung cancer, P-100 for breast cancer and JSKN016 for solid tumors.

P-100 was previously known as AZD4241 and is being developed with AstraZeneca. Pathos licensed JSKN016 from China's Alphamab Oncology in August under a deal that included $125 million upfront and up to $2.09 billion in milestone payments.

Partnerships with Bristol Myers and Tempus

Pathos today also announced new agreements with Bristol Myers and Nasdaq-listed healthcare technology company Tempus AI.

Bristol Myers will be able to use Foundry for its drug development work. It will also have exclusive rights for three years to use the platform for its neuroscience drugs.

The companies will first focus on Alzheimer's disease and other conditions affecting the brain and nervous system.

"AI has the greatest potential when it is grounded in high-quality data and applied by scientists with deep understanding of diseases and drug development,” said Simon Davies, senior vice president and head of data and quantitative sciences at Bristol Myers Squibb. "Collaborating with Pathos and Tempus allows us to interrogate Alzheimer’s and other neurological diseases at scale, strengthening our pipeline and advancing precision medicine for patients in need.”

Under a separate five-year agreement, Pathos will pay Tempus up to $55 million for data from patients with Alzheimer's disease and other neurological conditions.

Tempus agreed to provide up to 500,000 de-identified patient records, with a target of 100,000 records each year, according to a regulatory filing.

Pathos' funding comes as other AI drug development startups have also raised large rounds. Last month, ByteDance spinout Anew Labs raised $290 million at a $1.5 billion valuation. Google DeepMind spinout Isomorphic Labs raised $2.1 billion in May, and Chai Discovery raised $400 million at a $3.8 billion valuation in July.

Other notable rounds this year include Earendil Labs, which raised $787 million in March, and Enveda, which raised $311 million in a Series E last month.