Predictors of severe hematotoxicity after CAR T-cell therapy.
Authors: Emily C. Liang, Aya Albittar, Andrew Jay Portuguese, Jennifer Jing Huang, Aiko Torkelson, Delaney Kirchmeier, Abigail Chutnik, Barbara Pender, Joshua A. Hill, Noam Edward Kopmar, Rahul Banerjee, Andrew Cowan, Christina Poh, Mazyar Shadman, Alexandre V. Hirayama, Brian G. Till, Erik Lesley Kimble, Lorenzo Iovino, Ryan Daniel Cassaday, Jordan Gauthier
Journal: Journal of Clinical Oncology (2024)

7024 Background: The EHA/EBMT immune effector cell-associated hematotoxicity (ICAHT) grading system characterizes hematotoxicity after CAR T-cell therapy based on depth and duration of neutropenia (Rejeski et al, Blood, 2023). We evaluated pre- and post-infusion factors associated with grade 3-4 ICAHT and developed a predictive model in 602 patients with hematologic malignancies undergoing CAR T-cell therapy at Fred Hutch Cancer Center. Methods: Grading of early hematotoxicity (day-0-30 after CAR T-cell cell infusion) was automated using the heatwaveR package. Associations with 50 patient, disease-related, and laboratory factors, and grade 3-4 ICAHT were modeled using univariate and multivariable logistic regression. Results: The most common disease types were aggressive non-Hodgkin lymphoma (NHL; n = 293; 49%), indolent NHL (n = 150; 25%), and acute lymphoblastic leukemia (ALL; n = 94; 16%). The most common CAR T-cell products were the investigational CD19 CAR T-cell product JCAR014 (n = 197; 33%), axicabtagene ciloleucel (n = 129; 21%), and lisocabtagene maraleucel (n = 73; 12%). Incidences of early ICAHT grades 1, 2, 3, and 4 were 319 (53%), 96 (16%), 60 (10%), and 35 (6%) patients, respectively. Baseline patient factors associated with grade 3-4 ICAHT included ALL (reference: aggressive NHL, OR = 4.18, 95% CI, 2.41-7.26, p &lt; 0.001) , Hispanic or Latino ethnicity (OR = 2.17, 95% CI, 1.07-4.20, p = 0.025), and lower age (OR = 1.03, 95% CI, 1.02-1.05, p &lt; 0.001). Pre-lymphodepletion (LD) laboratory factors associated with grade 3-4 ICAHT in univariate analyses included lower ANC (OR = 6.67 per log10 cells/μL, 95% CI, 4.0-11.1, p &lt; 0.001), LDH (OR = 8.70per log10U/L, 95% CI, 4.03-19.4, p &lt; 0.001), CRP (OR = 3.18 per log10mg/L, 95% CI, 2.06-5.07, p &lt; 0.001), and ferritin (OR = 6.07 per log10mg/L, 95% CI, 3.65-10.6, p &lt; 0.001). Peak CRP (OR = 15.6, 95% CI, 7.27-36.4, p &lt; 0.001), peak ferritin (OR = 7.41, 95% CI, 5.02-11.3, p &lt; 0.001), peak CRS grade (OR = 2.01, 95% CI, 1.59-2.56, p &lt; 0.001), and peak ICANS grade (OR = 1.51, 95% CI, 1.29-1.77, p &lt; 0.001) after CAR T-cell infusion were also strongly associated with grade 3-4 ICAHT. A multivariable model using restricted cubic splines and including disease type, pre-LD ANC, pre-LD LDH, peak CRP, peak ferritin, and CRS grade demonstrated high discrimination to predict grade 3-4 ICAHT (C-index = 0.89). Internal validation using bootstrapping showed near-perfect calibration without overfitting. Sensitivity and specificity based on the Youden criteria was 74% and 90%, respectively. The sensitivity and specificity of the CAR-HEMATOTOX score in predicting grade 3-4 ICAHT was 93% and 30%, respectively. Conclusions: We identified pre- and post-infusion predictors of grade 3-4 ICAHT and internally validated a multivariable logistic regression model including disease-type, pre-LD ANC, pre-LD LDH, peak CRP, peak ferritin, and CRS grade. We plan to further evaluate our model in an external cohort.