Endothelial Activation and Stress Index Score as a Prognostic Factor of Cytokine Release Syndrome in CAR-T Patients – A Retrospective Analysis of Multiple Myeloma and Large B-Cell Lymphoma Cohorts

Endothelial Activation and Stress Index (EASIX) has been proposed as a prognostic factor of adverse events or survival in hematological malignancies. Endothelial dysfunction has been associated with complications following stem cell transplantation and chimeric antigen receptor (CAR)-T therapy. This retrospective cohort study evaluated the utility of the EASIX score as a prognostic factor of cytokine release syndrome (CRS) in multiple myeloma/light-chain amyloidosis (MM/AL amyloidosis; N = 69) and large B-cell lymphoma (LBCL) cohorts (N = 65). Occurrence of CRS grade ≥3 was the primary endpoint. For both cohorts, the EASIX and simplified EASIX (s-EASIX) scores were calculated at four different time points before CAR-T infusion to assess its prognostic value. In the MM/AL amyloidosis cohort, neither EASIX nor s-EASIX scores calculated at any time point were associated with the occurrence of CRS grade ≥3. In the LBCL cohort, EASIX and s-EASIX scores measured before lymphodepletion (EASIX-pre and s-EASIX-pre) showed a significant relationship with CRS grade ≥3 (odds ratio [OR] = 1.06 and OR = 1.05, respectively). The cutoff value of 1.835 for EASIX-pre was associated with 4.59-fold increased OR of CRS grade ≥3 (95% confidence interval [CI]: 1.13-21.84), whereas s-EASIX-pre cutoff equaled 2.134 and was associated with 4.13-fold increased OR of CRS grade ≥3 (95% CI: 1.01-17.93). However, after internal validation with bootstrapping, the significance was lost both for the EASIX-pre and s-EASIX-pre cutoff. The presented findings indicate that the EASIX scores fail to predict CRS in MM/amyloidosis CAR-T patients, whereas they can be implemented as CRS grade ≥3 predictors in LBCL CAR-T patients.