Ariel Perez Perez

Hematotoxicity represents a frequent chimeric antigen receptor (CAR) T-cell-related adverse event and remains poorly understood. In this multicenter analysis, we studied patterns of hematopoietic reconstitution and evaluated potential predictive markers in 258 patients receiving axicabtagene ciloleucel (axi-cel) or tisagenlecleucel (tisa-cel) for relapsed/refractory large B-cell lymphoma. We observed profound (absolute neutrophil count [ANC] <100 cells per µL) neutropenia in 72% of patients and prolonged (21 days or longer) neutropenia in 64% of patients. The median duration of severe neutropenia (ANC < 500 cells per µL) was 9 days. We aimed to identify predictive biomarkers of hematotoxicity using the duration of severe neutropenia until day +60 as the primary end point. In the training cohort (n = 58), we observed a significant correlation with baseline thrombocytopenia (r = -0.43; P = .001) and hyperferritinemia (r = 0.54; P < .0001) on univariate and multivariate analysis. Incidence and severity of cytokine-release syndrome, immune effector cell-associated neurotoxicity syndrome, and peak cytokine levels were not associated with the primary end point. We created the CAR-HEMATOTOX model, which included markers associated with hematopoietic reserve (eg, platelet count, hemoglobin, and ANC) and baseline inflammation (eg, C-reactive protein and ferritin). This model was validated in independent cohorts, one from Europe (n = 91) and one from the United States (n = 109) and discriminated patients with severe neutropenia ≥14 days to <14 days (pooled validation: area under the curve, 0.89; sensitivity, 89%; specificity, 68%). A high CAR-HEMATOTOX score resulted in a longer duration of neutropenia (12 vs 5.5 days; P < .001) and a higher incidence of severe thrombocytopenia (87% vs 34%; P < .001) and anemia (96% vs 40%; P < .001). The score implicates bone marrow reserve and inflammation prior to CAR T-cell therapy as key features associated with delayed cytopenia and will be useful for risk-adapted management of hematotoxicity.

Background CD19-directed chimeric antigen receptor T-cell therapy (CAR-T) represents a promising treatment modality for an increasing number of B-cell malignancies. However, prolonged cytopenias and infections substantially contribute to the toxicity burden of CAR-T. The recently developed CAR-HEMATOTOX (HT) score—composed of five pre-lymphodepletion variables (eg, absolute neutrophil count, platelet count, hemoglobin, C-reactive protein, ferritin)—enables risk stratification of hematological toxicity. Methods In this multicenter retrospective analysis, we characterized early infection events (days 0–90) and clinical outcomes in 248 patients receiving standard-of-care CD19 CAR-T for relapsed/refractory large B-cell lymphoma. This included a derivation cohort (cohort A, 179 patients) and a second independent validation cohort (cohort B, 69 patients). Cumulative incidence curves were calculated for all-grade, grade ≥3, and specific infection subtypes. Clinical outcomes were studied via Kaplan-Meier estimates. Results In a multivariate analysis adjusted for other baseline features, the HT score identified patients at high risk for severe infections (adjusted HR 6.4, 95% CI 3.1 to 13.1). HT high patients more frequently developed severe infections (40% vs 8%, p&lt;0.0001)—particularly severe bacterial infections (27% vs 0.9%, p&lt;0.0001). Additionally, multivariate analysis of post-CAR-T factors revealed that infection risk was increased by prolonged neutropenia (≥14 days) and corticosteroid use (≥9 days), and decreased with fluoroquinolone prophylaxis. Antibacterial prophylaxis significantly reduced the likelihood of severe bacterial infections in HT high (16% vs 46%, p&lt;0.001), but not HT low patients (0% vs 2%, p=n.s.). Collectively, HT high patients experienced worse median progression-free (3.4 vs 12.6 months) and overall survival (9.1 months vs not-reached), and were hospitalized longer (median 20 vs 16 days). Severe infections represented the most common cause of non-relapse mortality after CAR-T and were associated with poor survival outcomes. A trend toward increased non-relapse mortality in HT high patients was observed (8.0% vs 3.7%, p=0.09). Conclusions These data demonstrate the utility of the HT score to risk-stratify patients for infectious complications and poor survival outcomes prior to CD19 CAR-T. High-risk patients likely benefit from anti-infective prophylaxis and should be closely monitored for potential infections and relapse.

Prolonged cytopenias after chimeric antigen receptor (CAR) T cell therapy are a significant clinical problem and the underlying pathophysiology remains poorly understood. Here, we investigated how (CAR) T cell expansion dynamics and serum proteomics affect neutrophil recovery phenotypes after CD19-directed CAR T cell therapy. Survival favored patients with "intermittent" neutrophil recovery (e.g., recurrent neutrophil dips) compared to either "quick" or "aplastic" recovery. While intermittent patients displayed increased CAR T cell expansion, aplastic patients exhibited an unfavorable relationship between expansion and tumor burden. Proteomics of patient serum collected at baseline and in the first month after CAR-T therapy revealed higher markers of endothelial dysfunction, inflammatory cytokines, macrophage activation, and T cell suppression in the aplastic phenotype group. Prolonged neutrophil aplasia thus occurs in patients with systemic immune dysregulation at baseline with subsequently impaired CAR-T expansion and myeloid-related inflammatory changes. The association between neutrophil recovery and survival outcomes highlights critical interactions between host hematopoiesis and the immune state stimulated by CAR-T infusion.

Allogeneic hematopoietic cell transplantation (allo-HCT) is a curative treatment option for patients with acute lymphoblastic leukemia (ALL). Both total body irradiation (TBI)-based and chemotherapy only-based myeloablative transplantation conditioning regimens have been applied, but the optimal regimen remains unclear. We performed a systematic review to assess the efficacy of TBI-based versus chemotherapy only-based myeloablative conditioning regimens. We searched PubMed, Embase, and Cochrane databases and meeting abstracts for all studies comparing TBI-based and chemotherapy only-based conditioning regimens in patients who underwent allo-HCT for ALL. Two authors independently reviewed all studies for inclusion and extracted data related to overall survival (OS), progression-free survival (PFS), nonrelapse mortality (NRM), relapse, and acute and chronic graft-versus-host disease (GVHD). Eight studies were included in the final analysis. The overall methodological quality of the included studies was optimal. TBI-based regimens showed evidence of benefit compared with chemotherapy only-based conditioning regimens in terms of relapse (relative risk [RR], 0.82; 95% confidence interval [CI], 0.72 to 0.94; 6 studies, 5091 patients), OS (hazard ratio [HR], 0.76; 95% CI, 0.64 to 0.89; 7 studies, 4727 patients), and PFS (HR, 0.74; 95% CI, 0.63 to 0.85; 7 studies, 4727 patients). The TBI-based regimen did not increase the likelihood of grade II-IV acute GVHD (RR, 1.12; 95% CI, 0.92 to 1.36; 5 studies, 4996 patients) or chronic GVHD (RR, 1.10; 95% CI, 1.00 to 1.21; 5 studies, 4490 patients), or NRM (RR, 0.94; 95% CI, 0.69 to 1.28; 6 studies, 4522 patients). However, TBI-based regimens were associated with an increased risk of grade III-IV acute GVHD (RR, 1.29; 95% CI, 1.01 to 1.63; 3 studies, 3675 patients). A subgroup comparison of patients age ≥16 years showed similar results. This systematic review represents evidence supporting the use of TBI-based conditioning regimen in patients undergoing allo-HCT for ALL who are candidates for myeloablative conditioning, as it offers better OS, PFS, and less relapse with acceptable NRM.