Infection epidemiology in relation to different therapy phases in patients with haematological malignancies receiving CAR T-cell therapy

Background: We described the real-life epidemiology and causes of infections on the different therapy phases in patients undergoing chimeric antigen receptor (CAR) T-cells directed towards CD19+ or BCMA+ cells.Methods: All consecutive patients receiving CAR T-cell therapy at our institution were prospectively followed-up. We performed various comparative analyses of all patients and subgroups with and without infections.Results: Ninety-one adults mainly received CAR T-cell therapy for acute leukaemia (53%) and lymphoma (33%). We documented a total of 77 infections in 47 (52%) patients, 37 (48%) during the initial neutropenic phase and 40 (52%) during the non-neutropenic phase. Infections during the neutropenic phase were mainly due to bacterial (29, 78%): catheter infections (11 [38%] cases), endogenous source (5 [17%]), and Clostridioides difficile (5 [17%]). Patients receiving corticosteroids after CAR T-cell therapy had a higher risk of endogenous infection (100% vs. 16%; p = .006). During the non-neutropenic phase, bacterial infections remained very frequent (24, 60%), mainly with catheter source (8, 33%). Respiratory tract infections were common (17, 43%).Conclusions: Infections after CAR T-cell therapy were frequent. During the neutropenic phase, it is essential to prevent nosocomial infections and balance the use of antibiotics to lower endogenous bacteraemia and Clostridial infection rates.