Cited by 1,276Chronic Lymphocytic Leukemia ResearchLymphoma Diagnosis and TreatmentLung Cancer Treatments and Mutations

The DOI matches its Crossref record; 34 of the 34 references it cites were found in a registry or an index; 17 of the 19 sources its claims cite were checked for support.

Resistance Mechanisms for the Bruton's Tyrosine Kinase Inhibitor Ibrutinib

Open access

Abstract

BACKGROUND: Ibrutinib is an irreversible inhibitor of Bruton's tyrosine kinase (BTK) and is effective in chronic lymphocytic leukemia (CLL). Resistance to irreversible kinase inhibitors and resistance associated with BTK inhibition have not been characterized. Although only a small proportion of patients have had a relapse during ibrutinib therapy, an understanding of resistance mechanisms is important. We evaluated patients with relapsed disease to identify mutations that may mediate ibrutinib resistance. METHODS: We performed whole-exome sequencing at baseline and the time of relapse on samples from six patients with acquired resistance to ibrutinib therapy. We then performed functional analysis of identified mutations. In addition, we performed Ion Torrent sequencing for identified resistance mutations on samples from nine patients with prolonged lymphocytosis. RESULTS: We identified a cysteine-to-serine mutation in BTK at the binding site of ibrutinib in five patients and identified three distinct mutations in PLCγ2 in two patients. Functional analysis showed that the C481S mutation of BTK results in a protein that is only reversibly inhibited by ibrutinib. The R665W and L845F mutations in PLCγ2 are both potentially gain-of-function mutations that lead to autonomous B-cell-receptor activity. These mutations were not found in any of the patients with prolonged lymphocytosis who were taking ibrutinib. CONCLUSIONS: Resistance to the irreversible BTK inhibitor ibrutinib often involves mutation of a cysteine residue where ibrutinib binding occurs. This finding, combined with two additional mutations in PLCγ2 that are immediately downstream of BTK, underscores the importance of the B-cell-receptor pathway in the mechanism of action of ibrutinib in CLL. (Funded by the National Cancer Institute and others.).

Overview

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Written from the paper’s full text.

TL;DR

Acquired resistance to ibrutinib in CLL often involves BTK C481S or PLCγ2 mutations that restore B-cell–receptor signaling. Functional studies show C481S prevents irreversible BTK binding, while PLCγ2 R665W/L845F are gain-of-function and BTK-independent.

Key findings

  • Whole-exome sequencing of six patients with acquired ibrutinib resistance identified BTK C481S in five patients and PLCγ2 mutations in two patients: R665W in Patient 6, and R665W, L845F, plus S707Y in one patient who also had low-frequency BTK C481S.
  • C481S BTK had lower ibrutinib affinity than nonmutant BTK (dissociation constant, 0.2 nM vs. 10.4 nM) and was only reversibly inhibited by ibrutinib; washout experiments in patient cells showed inhibition required continuous drug exposure.
  • PLCγ2 R665W and L845F showed enhanced anti-IgM–mediated calcium flux that was not inhibited by ibrutinib, indicating potential gain-of-function mutations allowing BTK-independent B-cell–receptor signaling.
  • No BTK or PLCγ2 mutations were found in nine patients with prolonged lymphocytosis (≥12 months) on ibrutinib; sequencing depth was >700 reads for BTK C481 and PLCγ2 R665/S707 and >100 reads for PLCγ2 L845.

Methods

  • Whole-exome sequencing was performed on baseline and relapse samples from six patients with acquired resistance to ibrutinib; relapse-specific nonsynonymous mutations were verified by Sanger or Ion Torrent sequencing.
  • Ion Torrent sequencing was used to test for BTK and PLCγ2 mutations in nine patients with prolonged lymphocytosis during ibrutinib therapy.
  • Functional analyses included in vitro kinase assays, flow cytometry, immunoblot assays, and stable transfection into DT40 or HEK 293T cells; statistical methods were detailed in the Supplementary Appendix.

Limitations

  • The paper states that inability to identify small numbers of mutant clones in the presence of large numbers of nonmutant clones may mean such variants were present but not identified; the clinical significance of very low baseline R665W variant reads is unknown and more patients need evaluation.
  • The paper states that other resistance mechanisms are likely present in a subgroup of patients without B-cell–receptor pathway mutations, and work is ongoing to identify alternative mechanisms.
  • Evident from the text: the study is based on a small number of patients (six with acquired resistance and nine with prolonged lymphocytosis), limiting generalizability and statistical power.

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Integrity signals

Registry

Crossref · 10.1056/nejmoa1400029

Cites

34 of 34 references verified0 citation errors · 0 not checkable

Statistics

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Verification

Claims the paper makes

17 of 19 cited sources checked · 4 supported · 0 flagged · accuracy not yet measured

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  • It may state two separate claims as one. 11
  • The quote only partly states this claim. 2
  • Probably not a substantial claim. 1
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Self-check

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Each contradiction between two passages listed here was confirmed by an independent check.

  • ALK resistance claim cites a ROS1 mutation study

    Minor

    The text cites reference 27 as an example of resistance through an ALK mutation, but reference 27 is titled as a report of resistance from a CD74-ROS1 mutation.

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Metadata

Authors
Woyach, J. A., Furman, R. R., Liu, T.-M., Ozer, H. G., Zapatka, M., Ruppert, A. S., Xue, L., Li, D. H.-H., Steggerda, S. M., Versele, M., Dave, S. S., Zhang, J., Yilmaz, A. S., Jaglowski, S. M., Blum, K. A., Lozanski, A., Lozanski, G., James, D. F., Barrientos, J. C., Lichter, P., Stilgenbauer, S., Buggy, J. J., Chang, B. Y., Johnson, A. J., & Byrd, J. C.
Affiliations
  • German Cancer Research Center (DE)
  • Weill Cornell Medicine (US)
  • Pharmacyclics (United States) (US)
  • Janssen (Belgium) (BE)
  • Duke University (US)
  • The Ohio State University (US)
  • Northwell Health (US)
  • Universität Ulm (DE)
Venue
New England Journal of Medicine
Published
2014-06-12
Volume
370
Issue
24
Pages
2286-2294
ISSN
  • 0028-4793 (ISSN-L)
  • 1533-4406
OpenAlex
W2067064694
Cited by
1,275
References
34
Citations by year
2026: 50 · 2025: 77 · 2024: 91 · 2023: 99 · 2022: 102 · 2021: 143 · 2020: 122 · 2019: 99 · 2018: 98 · 2017: 126 · 2016: 118 · 2015: 108 · 2014: 39
FWCI
58.67
Type
journal article
Language
en
Open access
Locations
  • New England Journal of Medicine (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (submittedVersion)
Funders
  • National Institutes of Health (4p01ca081534-16, 5k12ca133250-17, 2p30ca014236-51)
  • National Cancer Institute (P30‐CA014236, R01CA183444, P01CA095426, K12‐CA133250, P50CA140158, K23 CA178183, R01CA177292, P30CA016058, P01-CA-081534)
Topics
  • Health Sciences › Medicine › Hematology › Chronic Lymphocytic Leukemia Research
  • Health Sciences › Medicine › Pathology and Forensic Medicine › Lymphoma Diagnosis and Treatment
  • Health Sciences › Medicine › Pulmonary and Respiratory Medicine › Lung Cancer Treatments and Mutations
Keywords
ibrutinib, Bruton's tyrosine kinase, chronic lymphocytic leukemia, drug resistance, B cell receptor signaling, irreversible kinase inhibitors, relapsed disease
MeSH terms
Agammaglobulinaemia Tyrosine Kinase, Adenine, Aged, Binding Sites, Humans, Middle Aged, Piperidines, Protein-Tyrosine Kinases, Pyrazoles, Pyrimidines, Receptors, Antigen, B-Cell, Recurrence, Leukemia, Lymphocytic, Chronic, B-Cell, Point Mutation, Sequence Analysis, DNA, Drug Resistance, Neoplasm, Phospholipase C gamma, Exome

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