Orally effective FDA-approved protein kinase targeted covalent inhibitors (TCIs): A 2025 update

Because aberrations of protein kinase activity play causal roles in several human diseases, this family of enzymes is one of the most important drug targets of the 21st century. Of the 88 protein kinase antagonists that are approved by the FDA, eleven of them form irreversible covalent complexes with their target enzymes. The clinical efficacy of ibrutinib, a Bruton tyrosine kinase blocker, in the treatment of mantle cell lymphoma following its 2013 approval helped to overcome a general bias against the development of irreversible drug inhibitors. Other approved targeted covalent inhibitors include acalabrutinib and zanubrutinib, which also block Bruton tyrosine kinase. Afatinib, dacomitinib, lazertinib, mobocertinib, and osimertinib inhibit members of the epidermal growth factor receptor family (ErbB1/2/3/4) and are used in the treatment of non-small cell lung cancers. Neratinib inhibits ErbB2 and is used in the management of ErbB2/HER2-positive breast cancer. Futibatinib blocks the fibroblast growth factor receptor family and is prescribed for the treatment of cholangiocarcinoma while ritlecitinib, which inhibits JAK3, is used in the management of alopecia areata. The eleven drugs considered in this review have a common mechanism of action involving the addition of a protein cysteine thiolate anion (proteinS:) to an acrylamide or an acrylamide-like derivative producing a thioether. The development of targeted covalent inhibitors is gaining acceptance as a valuable component of the medicinal chemist's toolbox and has made a significant impact on the development of protein kinase antagonists and receptor modulators.