1. Characterization of lymphopenia and correlating the risk of cytopenias with dose and BM volume irradiated in aggressive B-cell lymphoma patients bridged with radiation therapy for CAR-T cell therapy.
- Author
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Manzar GS, Wu SY, Dudzinski SO, Cha EE, Yoder AK, Corrigan KL, Nasr LF, Sallard G, Ahmed S, Fayad LE, Chihara D, Nair R, Westin JR, Daher M, Neelapu SS, Nastoupil LJ, Gunther JR, Pinnix CC, Dabaja BS, Strati P, and Fang PQ
- Abstract
Introduction: The impact of bridging radiation therapy (bRT) for CAR T-cell therapy on absolute lymphocyte count (ALC) kinetics and treatment outcome is unknown., Methods: We retrospectively reviewed adults with relapsed/refractory aggressive large B-cell lymphoma (LBCL) who received bRT prior to CD-19 CAR-T between 11/2017-4/2023. The change in ALC (ALC Δ RT) was computed by subtracting ALC pre- and post-bRT. Percent bone marrow (%BM) irradiated was calculated by estimating skeletal BM distribution. PFS, DSS, and OS were modeled via Kaplan-Meier., Results: Fifty-one patients received bRT, of which 13 (25.5%) had bulky disease (≥7.5cm). The median bRT dose was 30Gy (range: 4-48Gy); 26 patients (51%) received ≥30Gy. Thirty-one patients (61%) received bRT comprehensively to all disease sites. The median cumulative %BM irradiated was 5.05% (range: 0-50%). At a median follow-up of 10.3 months (95% CI: 7.7-16.4), the 1-year OS, PFS, and DSS rates were 80% (95% CI: 66-99), 78% (64-87), and 82% (68-90), respectively. The incidence of ≥Grade 3 lymphopenia was 33% pre-RT and 68% post-RT, but recovered to 43% at the conditioning chemotherapy (CC) timepoint. There was no correlation between post-RT Grade ≥3 lymphopenia and the receipt of comprehensive bRT, combined modality bridging, ≥30Gy bRT, or bRT to ≥15% of BM (all p>0.2). Among patients with Grade 0-2 lymphopenia pre-RT, increased conversion to Grade ≥3 lymphopenia post-RT correlated with comprehensive or ≥30Gy bRT, but these factors did not impair ALC recovery at CC. There was no association between ALC Δ RT or post-RT ALC with 30 or 90 day response (p>0.25), DSS, PFS, or OS (p>0.3)., Conclusions: Lymphocyte change during bRT is not associated with CAR-T outcomes. Persistent cytopenia risk following bRT is not associated with bRT to ≥30Gy, ≥15% of BM, or comprehensive coverage. While bRT can be delivered safely, we urge careful treatment planning when incorporating into pre-CAR-T regimens., (Copyright © 2024. Published by Elsevier Inc.)
- Published
- 2024
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