Infectious complications following chimeric antigen receptor (CAR) T cell therapy are common; often unique infections may arise during the follow up period; some unique risk factors for infection following CAR T cell therapy multiple lines of therapy, lymphodepleting conditioning and immunosuppression for cytokine release syndrome (CRS) or effector cell-associated neurotoxicity syndrome (ICANS). Due to the lack of definitive data on prophylaxis in CAR T cell recipients, prophylactic regimens mimic those recommended for autologous hematopoietic cell transplant (Auto HCT) recipients. In our study, we compared the infectious complications and timing of infections between Auto HCT and CD19 CAR T cell recipients within a year from cellular infusion. We included all consecutive CAR T and Auto HCT recipients between January 2018 and February 2021 for treatment of lymphoma and ALL. Patients were followed for 1 year for any bacterial, viral or fungal infections. For bacterial or fungal infections, we included patients receiving antimicrobials for suspected or possible cases; viral infections required a microbiologic diagnosis. Infections that occurred during conditioning/lymphodepletion were included. We compared rate of each infectious etiology and time to infection between CAR T cell and Auto HCT recipients using Fisher exact test or Wilcoxon rank sum as appropriate. A total of 427 cellular therapy recipients were identified, 10 were excluded due to incomplete follow-up data. Of the 417 patients included, 233 (56%) and 184 (44%) underwent CAR T cell therapy or Auto HCT during the study period, respectively. Table 1 depicts baseline characteristics between the 2 cohorts. The CAR T cell group included more patients with diffuse large B cell lymphoma and acute lymphoblastic leukemia, while the autologous HCT group included more patients with follicular lymphoma and mantle cell lymphoma. Bacterial were the most common type of infections in either group with similar time to onset, but more fungal infections were identified after CAR T cell therapy (29 (12%) vs. 8 (4%), p=0.005) (table 2); infections were commonly mold or Candida related infections. When compared to Auto HCT, viral infections occurred sooner (median of 29 days vs. 147 days, p<0.001), and (Table 2). CAR T cell therapy recipients may develop viral infections earlier following cellular therapy; this is likely related to clinically significant cytomegalovirus. More fungal infections occurred after CAR T cell therapy with a trend for sooner onset. Larger studies are needed to better compare the outcomes of these infectious complications between these 2 cohorts.
Angelidakis et al. (Sun,) studied this question.