Abstract To explore the role of clonal hematopoiesis (CH) on chimeric antigen receptor (CAR) T-cell therapy outcomes, we performed targeted deep-sequencing on 114 large B-cell lymphoma patients treated with anti-CD19 CAR T-cells. We detected CH in 42 (36.8%) pre-treatment patient samples, most frequently in PPM1D (19/114) and TP53 (13/114) genes. The incidence of grade ≥3 immune-effector cell-associated neurotoxicity syndrome (ICANS) was higher in CH-positive patients compared to CH-negative patients (45.2% vs. 25.0%, p=0.038). Higher toxicities with CH were primarily driven by three CH genes, DNMT3A, TET2 and ASXL1 (DTA mutations). The incidence of grade ≥3 ICANS [58.9% vs. 25%, p=0.02] and grade ≥3 cytokine release syndrome [17.7% vs. 4.2%, p=0.08] were higher in patients with DTA mutations than those without CH. The estimated 24-month cumulative incidence of therapy-related myeloid neoplasms after CAR-T therapy was higher in patients with CH than those without CH (19% [95%CI: 5.5-38.7] vs. 4.2% [95%CI: 0.3-18.4], p=0.028). Statement of Significance Our study reveals that clonal hematopoiesis mutations, especially those associated with inflammation ( DNMT3A, TET2, ASXL1 ), are associated with severe grade toxicities in lymphoma patients receiving anti-CD19 chimeric antigen receptor therapy. Further studies to investigate the mechanisms and interventions to improve toxicities in the context of CH are warranted.

Clonal hematopoiesis is associated with increased toxicity in large B-cell lymphoma patients treated with chimeric antigen receptor T cell therapy