Antitumor Activity of the Novel BTK Inhibitor TG-1701 Is Associated with Disruption of Ikaros Signaling in Patients with B-cell Non-Hodgkin Lymphoma

  • Clin Cancer Res. 2021 Dec 1;27(23):6591-6601. doi: 10.1158/1078-0432.CCR-21-1067.
Marcelo Lima Ribeiro  1  2 ,  Diana Reyes-Garau  1 ,  Meritxell Vinyoles  3  4  5 ,  Núria Profitós Pelejà  1 ,  Juliana Carvalho Santos  1 ,  Marc Armengol  1  6 ,  Miranda Fernández-Serrano  1  6 ,  Alícia Sedó Mor  1  6 ,  Joan J Bech-Serra  7 ,  Pedro Blecua  8 ,  Eva Musulen  8  9 ,  Carolina De La Torre  7 ,  Hari Miskin  10 ,  Manel Esteller  5  8  11 ,  Francesc Bosch  6  12  13 ,  Pablo Menéndez  3  4  5  11 ,  Emmanuel Normant  #  14 ,  Gaël Roué  #  15  6  12  13
Affiliations
  • 1. Lymphoma Translational Group, Josep Carreras Leukaemia Research Institute, Badalona, Spain.
  • 2. Laboratory of Immunopharmacology and Molecular Biology, Sao Francisco University Medical School, Braganca Paulista, São Paulo, Brazil.
  • 3. Stem Cell Biology, Developmental Leukemia and Immunotherapy Group, Josep Carreras Leukaemia Research Institute, Badalona, Spain.
  • 4. Department of Biomedicine, School of Medicine, University of Barcelona, Barcelona, Spain.
  • 5. Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Salud Carlos III, Barcelona, Spain.
  • 6. Autonomous University of Barcelona, Barcelona, Spain.
  • 7. Proteomics Unit, Josep Carreras Leukaemia Research Institute, Badalona, Spain.
  • 8. Cancer Epigenetics Group, Josep Carreras Leukaemia Research Institute, Badalona, Spain.
  • 9. Department of Pathology, Hospital Universitari General de Catalunya-Grupo Quironsalud, Sant Cugat del Vallès, Spain.
  • 10. TG Therapeutics, New York, New York.
  • 11. Instituciò Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
  • 12. Department of Hematology, Vall d'Hebron University Hospital, Barcelona, Spain.
  • 13. Experimental Hematology, Vall d'Hebron Institute of Oncology, Barcelona, Spain.
  • 14. TG Therapeutics, New York, New York. [email protected] [email protected].
  • 15. Lymphoma Translational Group, Josep Carreras Leukaemia Research Institute, Badalona, Spain. [email protected] [email protected].
  • # Contributed equally.
PMID: 34551904 DOI: 10.1158/1078-0432.CCR-21-1067
Abstract

Purpose: Despite the remarkable activity of Btk inhibitors (BTKi) in relapsed B-cell non-Hodgkin lymphoma (B-NHL), no clinically-relevant biomarker has been associated to these agents so far. The relevance of phosphoproteomic profiling for the early identification of BTKi responders remains underexplored.

Experimental design: A set of six clinical samples from an ongoing phase I trial dosing patients with chronic lymphocytic leukemia (CLL) with TG-1701, a novel irreversible and highly specific BTKi, were characterized by phosphoproteomic and RNA Sequencing (RNA-seq) analysis. The activity of TG-1701 was evaluated in a panel of 11 B-NHL cell lines and mouse xenografts, including two NF-κB- and BtkC481S-driven BTKi-resistant models. Biomarker validation and signal transduction analysis were conducted through Real-Time PCR, Western blot analysis, immunostaining, and gene knockout (KO) experiments.

Results: A nonsupervised, phosphoproteomic-based clustering did match the early clinical outcomes of patients with CLL and separated a group of "early-responders" from a group of "late-responders." This clustering was based on a selected list of 96 phosphosites with Ikaros-pSer442/445 as a potential biomarker for TG-1701 efficacy. TG-1701 treatment was further shown to blunt Ikaros gene signature, including YES1 and MYC, in early-responder patients as well as in BTKi-sensitive B-NHL cell lines and xenografts. In contrast, Ikaros nuclear activity and signaling remained unaffected by the drug in vitro and in vivo in late-responder patients and in BtkC481S, BtkKO, and noncanonical NF-κB models.

Conclusions: These data validate phosphoproteomic as a valuable tool for the early detection of response to Btk inhibition in the clinic, and for the determination of drug mechanism of action.

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