APOD: Agentic Population ODE Discovery for Pharmacological Digital Twins
APOD is a language-model agent that iteratively reasons over biological knowledge and fit diagnostics in an open-ended search space to discover a population digital twin, a shared ODE system with between-subject variability. On synthetic pharmacokinetic and tumor-dynamics benchmarks it recovered ground-truth structures in 94-100% of runs, 12-fold faster in median than a library-based search.