Factors associated with infection events after chimeric antigen receptor T-cell therapy for relapsed or refractory multiple myeloma

Chimeric antigen receptor (CAR) T-cell therapy is a new and effective method in relapsed or refractory (R/R) multiple myeloma (MM). This study was aimed to explore the risk factors of infection events.We retrospectively analyzed 68 patients with R/R MM who received CAR T-cell therapy at the Affiliated Hospital of Xuzhou Medical University from June 2017 to June 2021.35 patients received anti-CD19 combined with anti-BCMA CAR T-cell therapy and 33 patients received anti-BCMA CAR T-cell therapy alone.Infection events in patients who received ≥4 prior lines of treatment or with grade 3-5 cytokines released syndrome (CRS) mainly occurred within 4 months after CAR T-cell infusion(CTI). The duration of infection-free survival was positively correlated with progression-free survival of patients with R/R MM (R2 = 0.962, p < 0.001) and the first infection event was closely accompanied by the disease relapse or progression. Treatment lines (p = 0.05), duration of ANC<500 cells/mm3 after CTI (p = 0.036), CRS grade (p = 0.007) and treatment response (p < 0.001) were the independent risk factors associated with infection for a multivariable model. The infection incidence was higher in patients with dual CAR T-cell therapy than with mono CAR T-cell therapy18 months after CTI although no statistic differences were observed within 18 months.Infections after CTI were closely associated with more lines of prior treatment, longer duration of ANC<500 cells/mm3, higher grade CRS and poor treatment response. Infections tended to occur in the early stage after CTI in patients with more lines of prior treatment and higher grade CRS.