Synergism or mirage: Current progress and an empirical approach for elucidating combination drug effects

In the context of the multitarget paradigm, fixed-dose combination (FDC) drugs, that is, compounds that synergistically target multiple sites when combined, have gained attention for treating complex diseases like cancers and viral infections, as traditional single-drug approaches are often inadequate. This review examines current methods for evaluating and predicting drug synergism in advancing combination drug discovery, highlighting their limitations and providing a unified mathematical framework. Additionally, we present a novel solution to resolve these limitations and improve synergism evaluation, demonstrated through a case study with 20 pairs of FDA-approved chemotherapy drugs for colorectal cancer.