BigHat Biosciences has appointed Stefan Weigand as Chief Scientific Officer. Weigand joins from Roche, where he led Large Molecule Research, overseeing approximately 350 scientists and the company's biologics pipeline from discovery through Phase I. At Roche, Weigand doubled the biologics research organisation's output to five to six molecules entering first-in-human trials annually. His team established therapeutic platforms including BrainShuttle and CrossMab, enabling over 60 molecules to advance into clinical development. At BigHat, Weigand will lead scientific strategy across the company's AI-driven drug design platform, which combines generative protein design with high-throughput experimental cycles. The platform uses Bayesian optimisation and reinforcement learning to engineer antibodies and complex protein therapeutics.

BigHat Biosciences raised $124 million in Series B funding led by S32 on April 28, 2025, with a pre-money valuation of $180 million. Participants included Amgen, Bristol-Myers Squibb, Quadrille Capital, Gaingels, GRIDS Capital, Axial, Quain Investments, Andreessen Horowitz, 8VC, AME Cloud Ventures, and Kevin Moore.