Incidence, Recurrence, Timing, and Economic Impact of Infections After CAR T-Cell Therapy: A Real-World Analysis From...

Chimeric antigen receptor (CAR) T-cell therapy has transformed treatment of hematologic malignancies but causes profound immune dysfunction and a high infection risk. Real-world data on infection incidence and economic burden remain limited.

To characterize the incidence, recurrence, timing, and types of infections after CAR T-cell therapy and estimate infection-related clinic visits, hospitalizations, and patient out-of-pocket (OOP) costs.

This retrospective cohort study used Merative MarketScan Commercial Claims Database (2017 to 2022). Adults (≥18 years) receiving CAR T-cell therapy for hematologic malignancies were included. Infections were identified via International Classification of Diseases, Tenth Revision (ICD-10) codes and classified by pathogen (bacterial, viral, fungal, unspecified) and organ system. Infections were examined across post-infusion intervals (<30, 30-90, and >90 days) and incidence rates were reported per 100 patient-years. Bivariate analyses compared baseline characteristics by infection status. Infection-related outpatient visits, hospitalizations, length of stay (LOS), and OOP costs were evaluated.

Of 378 eligible patients, 213 (56%) developed ≥1 infection (289 events). Respiratory infections were the most common (34%). Overall incidence was 122 per 100 patient-years, peaking at 609 per 100 patient-years in days 30 to 90. Incidence differed significantly by hematologic malignancy subtype. Recurrent infections occurred in 157 patients (42%), totaling 1373 distinct events (median 4 per patient; IQR, 2 to 11) with respiratory tract infections also being the most common (30%). The median time from the first to recurrent infection was 24 days (IQR, 4 to 69). Recurrence varied significantly by malignancy subtype and patient age. A total of 127 patients (34%) had 447 infection-related outpatient visits, and 67 patients (18%) had 95 infection-related hospitalizations. Median LOS was 7 days (IQR, 3 to 14). Total OOP costs were approximately $7,800 for outpatient visits and $35,000 for hospitalizations.

Infections are common, recurrent, and burdensome after CAR T-cell therapy, driving substantial healthcare utilization and OOP costs. Risk-stratified prophylaxis and management strategies are needed throughout the treatment continuum.