Implicit Bayesian Markov Decision Process for Resource-Efficient Experimental Design in Drug Discovery

In drug discovery, researchers make sequential decisions to schedule experiments, aiming to maximize probability of success towards drug candidates while simultaneously minimizing expected costs. However, such tasks pose significant challenges due to complex trade-offs between uncertainty reduction and allocation of constrained resources in a high-dimensional state-action space. Traditional methods based on simple rule-based heuristics or domain expertise often result in either inefficient resource utilization due to risk aversion or missed opportunities arising from reckless decisions. To address these challenges, we developed a Implicit Bayesian Markov Decision Process (IB-MDP) algorithm that constructs an implicit MDP model of the environment’s dynamics by integrating historical data through a similarity-based metric, and enables effective planning by simulating future states and actions. To enhance the robustness of the decision-making process, the IB-MDP also incorporates an ensemble approach that recommends maximum likelihood actions to effectively balance the dual objectives of reducing state uncertainty and optimizing expected costs. Our experimental results demonstrate that the IB-MDP algorithm offers significant improvements over traditional rule-based methods by identifying optimal decisions that ensure more efficient use of resources in drug discovery.