Merck & Co. launched a multi-target AI drug discovery collaboration with Protillion Biosciences, with potential milestone payments up to $510 million. The partnership is built around Protillion’s “lab-in-the-loop” approach using its Prot-MaP on-chip antibody discovery platform to generate large, quantitative binding datasets for therapeutic antibody optimization. Merck will apply its discovery expertise to develop multiple therapy candidates from the collaboration. Protillion says Prot-MaP can characterize millions of antibody variants per run on Illumina sequencing flow cells, aiming to reduce overfitting and speed optimization for biologics. For the biotech industry, the agreement is a high-value signal that large pharma is scaling AI workflows tied to high-throughput wet-lab feedback loops, not just model training.