Sam Stanton, Coefficient Bio With Nan Li, Dimension Capital

Author: Samuel Stanton, Co-Founder & Member of Technical Staff, Coefficient Bio (Anthropic); Nan Li (moderator), Co-Founder & General Partner, Dimension Capital Collection: UNLOCK-2026-Sessions

Summary

This fireside chat at UNLOCK 2026 covers the founding, product development, and Anthropic acquisition of Coefficient Bio, a startup that built AI tools for scientific reasoning and clinical development decision-making. Sam Stanton, who co-founded Coefficient Bio and is now on Anthropic's technical staff following the acquisition, is interviewed by Nan Li, co-founder and general partner of Dimension Capital, which was a founding co-investor in Coefficient.

Stanton's path to Coefficient ran through a PhD in algorithmic decision-making under uncertainty, a collaboration with Peyton Greenside at Big Hat Biosciences, and three years at Genentech's Precision Design team working on lab-in-the-loop antibody engineering. At Genentech he identified that the bottleneck in drug discovery was not early-stage molecule design but clinical development decision-making — the portfolio decisions that determine which molecules advance. His co-founder Joyce Hong brought eight years of Roivant analytics experience, deeply understanding how clinical programs are assessed. Together they designed Coefficient as a tool for scientific reasoning and judgment in the clinical development process, not a molecular design system.

The core technical insight was that the models were already very smart, but the real work was "context engineering" — understanding exactly what information a model needs to reason well about a clinical program (papers, regulatory pathways, competitive landscape, market sizing), and just as importantly, what to exclude to avoid context bloat. Coefficient used this to build ergonomically excellent tools for models, spending significant effort on tool design that enabled the model to reliably call the right tools in the right order. The acquisition by Anthropic came after Coefficient was already collaborating closely with Anthropic's life science team, and was driven by alignment with Dario Amodei and Eric Voorhees's vision plus the belief that independence inside Anthropic would provide the best path to executing the mission.