Kinase-impaired BTK mutations are susceptible to clinical-stage BTK and IKZF1/3 degrader NX-2127.

Document Type

Article

Publication Date

2-2-2024

Keywords

JGM, Humans, Agammaglobulinaemia Tyrosine Kinase, Ikaros Transcription Factor, Leukemia, Lymphocytic, Chronic, B-Cell, Mutation, Phosphorylation, Protein Kinase Inhibitors, Signal Transduction, Proteolysis, Drug Resistance, Neoplasm

JAX Source

Science. 2024;383(6682):eadi5798.

ISSN

1095-9203

PMID

38301010

DOI

https://doi.org/10.1126/science.adi5798

Abstract

Increasing use of covalent and noncovalent inhibitors of Bruton's tyrosine kinase (BTK) has elucidated a series of acquired drug-resistant BTK mutations in patients with B cell malignancies. Here we identify inhibitor resistance mutations in BTK with distinct enzymatic activities, including some that impair BTK enzymatic activity while imparting novel protein-protein interactions that sustain B cell receptor (BCR) signaling. Furthermore, we describe a clinical-stage BTK and IKZF1/3 degrader, NX-2127, that can bind and proteasomally degrade each mutant BTK proteoform, resulting in potent blockade of BCR signaling. Treatment of chronic lymphocytic leukemia with NX-2127 achieves >80% degradation of BTK in patients and demonstrates proof-of-concept therapeutic benefit. These data reveal an oncogenic scaffold function of mutant BTK that confers resistance across clinically approved BTK inhibitors but is overcome by BTK degradation in patients.

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