ISSN 1866-8836
Клеточная терапия и трансплантация

BS-09. Generation of CAR-T cell product for the treatment of resistant CD19-positive B-cell lymphomas

Ihar M. Seviaryn1, Hanna A. Saurytskaya1, Nadezhda M. Bobrova1, Aliaksei A. Beliayeuski1, Tatiana M. Doroshenko1, Volha A. Kalenik1, Alexander A. Migas1, Anna S. Portyanko1, Natalia Y. Konoplya1

1 N. N. Alexandrov National Cancer Centre of Belarus, Lesnoy, Minsk Disrtict, Republic of Belarus
2 Belarusian Research Center for Pediatric Oncology, Hematology and Immunology, Borovliany, Minsk Disrtict, Republic of Belarus


Contact: Dr. Tatiana M. Doroshenko, phone: +375 17 389 9558, e-mail: dor_t_m@mail.com

doi 10.18620/ctt-1866-8836-2023-12-3-1-176

Summary

This work objective was to generate CAR-T lymphocytes from the autologous cells of patients with refractive/relapsing lymphomas and to estimate their clinical efficiency.

Materials and methods

CD4- and CD8-positive cell fractions were isolated by means of positive immunomagnetic separation and subsequently activated and expanded in IMDM medium supplemented with 10% serum and interleukins 7 and 15. The second generation anti-CD19 chimeric antigen receptor was introduced into lymphocytes by lentiviral transduction at day 2 from the start of activation. Cells were cultured for a period of 12 days from the moment of transduction. The immunophenotype of cells was determined by means of flow cytometry. The content of CAR- expressing cells was determined by measuring surface expression of truncated EGFR which was co-expressed with the chimeric antigen receptor gene from the common reading frame. Naïve T-cells were determined by staining for CD3, CD197 and CD45RO. Upon the end of expansion CAR-T cell content in the product was estimated, CD4+CAR+ and CD8+CAR+ cells were mixed together at 1:1 ratio and handed over to clinical departments of N.N. Alexandrov National Cancer Centre of Belarus. CAR-T cells were infused into 11 patients (7 male, 4 female, median age 40 years, range 23-63) with refractive forms of B-cell lymphoma.

Results

The purity of the separated CD4+ and CD8+ lymphocytes at the start of activation was 93.6±5.32% и 95.1±2.5% respectively (n=11). Upon the end of expansion, the populations were more than 99.5% pure. Naïve T cells content in CD4+ fraction was 20.5±3.42% at the start and 23.48±4.35% at the end of expansion with no statistical significance (p=0.69; n=11). Naïve T cells content in CD8+ fraction was 22.85±5.86% at the start and 39.93±6.21% at the end of expansion (p=0.04; n=11). Comparison of absolute numbers indicates a significant expansion of this fraction from 1.014·107±1.98·106 to 3.69·107±1.31·107 for CD4+ cells (p=0.0086, n=11) and from 8.48·106±1.71·106 to 2.97·107±7.99·106 for CD8+ cells (p=0.0039, n=11). Efficiency of genetic modification was 19.61±3.8% for CD4+ cells and 11.74±2.61% for CD8+ cells (n=11). The mean dose of infused CAR-T cells was 0.36·106 cells per kilogram of body mass. Expansion of CAR-T cells with resulting B-cell aplasia was observed in all patients. The median of observation was 6.2 months (range 2-21 months). Objective response rate was 100% (10/10), complete remission was observed in 9 patients, partial response – in 1 patient. One patient died because of complications before the clinical response. Overall 1-year survival was 77.9%. Frequency of grade III cytokine release syndrome (CRS) was 9.1%, grade I CRS – 18.2%. Grade II neurotoxicity was observed in 9.1% of patients, grade III and IV neurotoxicity cases were not observed.

Conclusion

The in-house produced anti-CD19 CAR-T cells showed their high clinical efficiency and an acceptable scale of side effects and treatment tolerance in the сuring of patients with refractive/relapsing B-cell lymphomas.

Keywords

CAR-T lymphocytes, B-cell lymphomas, immunotherapy.


Supplement 12-3
09/30/2023

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doi 10.18620/ctt-1866-8836-2023-12-3-1-176

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