Pfizer and Gordian Bio struck a collaboration to apply Gordian’s in vivo mosaic screening platform to prioritize obesity targets directly within visceral adipose tissue. Gordian will run large-scale pooled AAV mosaic screens in epididymal and retroperitoneal white adipose tissue to map causal biology across hundreds of genes simultaneously in the living tissue microenvironment. Gordian’s CEO described the collaboration as platform-first—aimed at moving from correlative human genetics to causal target validation in disease-relevant tissue that is difficult to model ex vivo. The approach pairs tissue-specific promoters, single-cell readouts, and pooled perturbations to capture multicellular interactions and physiologic mechanisms. For big pharma, the deal signals a willingness to invest in novel functional genomics tools that can de-risk target selection in metabolic disease. For academic and startup target-discovery ecosystems, it elevates in vivo functional screens as a route to high-confidence targets for therapeutic development.