Correspondence on "Synergy and Antagonism between Allosteric and Active-Site Inhibitors of Abl Tyrosine Kinase".

Soellner published on the interplay between allosteric and adenosine triphosphate (ATP)-competitive inhibitors of ABL kinase, showing that the latter preferably binds to different conformational states of ABL compared to allosteric agents that specifically target the ABL myristate pocket (STAMP) and deducing that asciminib cannot bind to ABL simultaneously with ATP-competitive drugs. These results are to some extent in line with ours, although our analyses of dose-response matrices from combinations of asciminib with imatinib, nilotinib or dasatinib, show neither synergy nor antagonism, but suggest additive antiproliferative effects on BCR-ABL-dependent KCL22 cells. Furthermore, our X-ray crystallographic, solution nuclear magnetic resonance (NMR), and isothermal titration calorimetry studies show that asciminib can bind ABL concomitantly with type-1 or -2 ATP-competitive inhibitors to form ternary complexes.

The Dawn of Allosteric BCR-ABL1 Drugs: From a Phenotypic Screening Hit to an Approved Drug.

Chronic myeloid leukemia (CML) is driven by the constitutive activity of the BCR-ABL1 fusion oncoprotein. Despite the great success of drugs that target the BCR-ABL1 ATP-binding site in transforming CML into a manageable disease, emerging resistance point mutations impair inhibitor binding, thereby limiting the effectiveness of these drugs. Recently, allosteric inhibitors that interact with the ABL1 myristate-binding site have been shown to awaken an endogenous regulatory mechanism and reset full-length BCR-ABL1 into an inactive assembled state.

The specificity of asciminib, a potential treatment for chronic myeloid leukemia, as a myristate-pocket binding ABL inhibitor and analysis of its interactions with mutant forms of BCR-ABL1 kinase.

Asciminib is a potent, orally bioavailable, investigational drug that specifically and potently inhibits the tyrosine kinase activity of native ABL1, together with that of the chimeric BCR-ABL1 oncoprotein which causes chronic myeloid leukemia (CML). In contrast to ATP-competitive BCR-ABL1 kinase inhibitors employed to treat CML that target multiple kinases, asciminib binds to the myristate binding pocket on the kinase domains of ABL1 and BCR-ABL1. Hitherto no drugs have been developed whose mechanism of action involves interacting with myristate binding pockets on proteins, and analysis of the structures of such binding sites in proteins other than ABL1/ABL2/BCR-ABL1 strongly suggest that asciminib will not bind to these with high affinity.

Correction: AMN107 (nilotinib): a novel and selective inhibitor of BCR-ABL.

A correction to this paper has been published and can be accessed via a link at the top of the paper.

Discovery of Asciminib (ABL001), an Allosteric Inhibitor of the Tyrosine Kinase Activity of BCR-ABL1.

Chronic myelogenous leukemia (CML) arises from the constitutive activity of the BCR-ABL1 oncoprotein. Tyrosine kinase inhibitors (TKIs) that target the ATP-binding site have transformed CML into a chronic manageable disease. However, some patients develop drug resistance due to ATP-site mutations impeding drug binding.