Fragment-based drug discovery (FBDD) has emerged in the past decade as a powerful tool for discovering drug leads. FBDD has played a role in discovery of 3 approved drugs (Vemurafenib, Venetoclax, and Erdafitinib) and at least 30 drugs that are in various stages of clinical development. A fragment-based approach is particularly valuable for more challenging classes of new targets (or “undruggable” targets) where more conventional screening (HTS) has already failed.

Drug-like compounds are often composed of several segmental fragments, any one substructure of a molecule could have affinity for a subpocket fingerprint shared between two or more proteins. There is a significant structure-activity relationship between fragment structure and drug properties. It is easier to find a small molecule that complements a particular subsite within a binding site than a larger molecule that is complementary to the entire site; thus, FBDD usually yields higher hit rates than HTS. In addition, it is easier for fragment optimization to generate leads with improved ADME profile by merging, linking or growing fragments.

It is commonly recognized that high-quality fragment library can increase the FBDD screening hit rate. To meet researchers' expectations, Targetmol created a drug fragment library consisting of 1119 fragments arising from the smart fragmentation of 2080 approved drugs and 1100 clinical compounds by structure review and applying many layers of industry recommended medchem filters, including PAINS.