T cell–driven venetoclax resistance in chronic lymphocytic leukemia: in vivo preclinical activity of opaganib
10 affiliations
- 1Instituto de Medicina Experimental (IMEX), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Academia Nacional de Medicina
- 2Instituto de Investigaciones Biomédicas en Retrovirus y SIDA (INBIRS), Universidad de Buenos Aires (UBA)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
- 3Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología, Inmunología, Biotecnología y Genética, Cátedra de Virología
- 4The Feinstein Institutes for Medical Research
- 5Instituto Alexander Fleming (IAF)
- 6Hospital Alemán
- 7Fundaleu
- 8Centro Médico Km 41
- 9Hospital General de Agudos Dr. Teodoro Álvarez
- 10Universidad de Buenos Aires, Facultad de Medicina, Departamento de Microbiología, Parasitología e Inmunología, Cátedra I de Inmunología
Abstract
Introduction: Venetoclax has transformed the treatment of chronic lymphocytic leukemia (CLL), yet therapeutic resistance remains a major clinical challenge. In addition to leukemia cell-intrinsic mechanisms, interactions with the immune microenvironment can profoundly reduce venetoclax sensitivity. We previously identified sphingosine kinase 2 (SPHK2) as a therapeutic vulnerability underlying T-cell-supported venetoclax resistance. Here, we investigated the contribution of CD4 ⁺ and CD8 ⁺ T cell subsets and their extracellular vesicles (EVs) to this resistant phenotype and evaluated the therapeutic activity of the SPHK2 inhibitor opaganib in vivo .
Methods: We evaluated the role of activated CD4 ⁺ and CD8 ⁺ T cells and their EVs in the development of the venetoclax-resistant phenotype in primary CLL cells. The in vivo activity of opaganib was assessed in a xenograft model generated by co-engraftment of primary CLL cells with autologous activated T cells. Mice were treated with venetoclax, opaganib, or their combination, and leukemic burden and the T cell compartment were evaluated. Anti-apoptotic BCL-2 family proteins were also assessed in residual leukemic cells.
Results: Activated CD4 ⁺ , but not CD8 ⁺ , T cells induced leukemic cell activation and venetoclax resistance, and CD4 ⁺ T cell-derived EVs were sufficient to reproduce this phenotype. In vivo , venetoclax monotherapy failed to reduce leukemic burden, confirming that adaptive interactions with the immune microenvironment are sufficient to sustain therapeutic resistance. Although opaganib alone showed minimal antileukemic activity, its combination with venetoclax reduced splenic leukemic burden by approximately 50% and remodeled the tumor-associated T-cell compartment, without consistent modulation of anti-apoptotic BCL-2 family proteins in residual leukemic cells.
Discussion: These findings are consistent with the notion that the therapeutic effects of opaganib extend beyond leukemic-cell-intrinsic mechanisms and may include modulation of the immune microenvironment. Our study shows that opaganib reduces microenvironment-driven venetoclax resistance in a preclinical CLL model in vivo , supporting its clinical evaluation in combination with BCL-2 inhibition.
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BibTeX
@article{martinez2026celldriven,
title = {{T cell–driven venetoclax resistance in chronic lymphocytic leukemia: in vivo preclinical activity of opaganib}},
author = {Valeria Judith Sarapura Martínez and Paula Soledad Pérez and Anita Ng and Yu-Ju Chen and Kelly Wong and Chiara Cassarino and Rosario Custidiano and Carolina Mahuad and Miguel A. Pavlovsky and Raimundo Fernando Bezares and Martin Bertini and Mercedes Borge and Mónica Vermeulen and Pablo Elías Morande and Mirta Giordano and Matías Ostrowski and Nicholas Chiorazzi and Shih-Shih Chen and Romina Gamberale},
journal = {Frontiers in Immunology},
year = {2026},
month = oct,
doi = {10.3389/fimmu.2026.1968413},
url = {https://www.frontiersin.org/articles/10.3389/fimmu.2026.1968413/full},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - T cell–driven venetoclax resistance in chronic lymphocytic leukemia: in vivo preclinical activity of opaganib
AU - Valeria Judith Sarapura Martínez
AU - Paula Soledad Pérez
AU - Anita Ng
AU - Yu-Ju Chen
AU - Kelly Wong
AU - Chiara Cassarino
AU - Rosario Custidiano
AU - Carolina Mahuad
AU - Miguel A. Pavlovsky
AU - Raimundo Fernando Bezares
AU - Martin Bertini
AU - Mercedes Borge
AU - Mónica Vermeulen
AU - Pablo Elías Morande
AU - Mirta Giordano
AU - Matías Ostrowski
AU - Nicholas Chiorazzi
AU - Shih-Shih Chen
AU - Romina Gamberale
PY - 2026
DA - 2026/10/15
JO - Frontiers in Immunology
DO - 10.3389/fimmu.2026.1968413
UR - https://www.frontiersin.org/articles/10.3389/fimmu.2026.1968413/full
AB - Introduction: Venetoclax has transformed the treatment of chronic lymphocytic leukemia (CLL), yet therapeutic resistance remains a major clinical challenge. In addition to leukemia cell-intrinsic mechanisms, interactions with the immune microenvironment can profoundly reduce venetoclax sensitivity. We previously identified sphingosine kinase 2 (SPHK2) as a therapeutic vulnerability underlying T-cell-supported venetoclax resistance. Here, we investigated the contribution of CD4 ⁺ and CD8 ⁺ T cell subsets and their extracellular vesicles (EVs) to this resistant phenotype and evaluated the therapeutic activity of the SPHK2 inhibitor opaganib in vivo . Methods: We evaluated the role of activated CD4 ⁺ and CD8 ⁺ T cells and their EVs in the development of the venetoclax-resistant phenotype in primary CLL cells. The in vivo activity of opaganib was assessed in a xenograft model generated by co-engraftment of primary CLL cells with autologous activated T cells. Mice were treated with venetoclax, opaganib, or their combination, and leukemic burden and the T cell compartment were evaluated. Anti-apoptotic BCL-2 family proteins were also assessed in residual leukemic cells. Results: Activated CD4 ⁺ , but not CD8 ⁺ , T cells induced leukemic cell activation and venetoclax resistance, and CD4 ⁺ T cell-derived EVs were sufficient to reproduce this phenotype. In vivo , venetoclax monotherapy failed to reduce leukemic burden, confirming that adaptive interactions with the immune microenvironment are sufficient to sustain therapeutic resistance. Although opaganib alone showed minimal antileukemic activity, its combination with venetoclax reduced splenic leukemic burden by approximately 50% and remodeled the tumor-associated T-cell compartment, without consistent modulation of anti-apoptotic BCL-2 family proteins in residual leukemic cells. Discussion: These findings are consistent with the notion that the therapeutic effects of opaganib extend beyond leukemic-cell-intrinsic mechanisms and may include modulation of the immune microenvironment. Our study shows that opaganib reduces microenvironment-driven venetoclax resistance in a preclinical CLL model in vivo , supporting its clinical evaluation in combination with BCL-2 inhibition.
SN - 1664-3224
ER -