((SLA-052)) (SLA-052) Infection-Related Hospitalization After CAR-T Cell Therapy in Commercially Insured Patients with Hematologic Malignancies

Background: Chimeric Antigen Receptor T (CAR-T) cell therapy has revolutionized the treatment of hematologic malignancies, improving patient outcomes since its approval in 2017. However, CAR-T therapy is associated with significant complications, including infections, which can contribute to non-relapse mortality.

Objectives: To evaluate infection-related hospitalizations and Emergency Department (ED) visits following CAR-T cell therapy in commercially insured patients with hematologic malignancies.

Methods: This retrospective cohort study utilized the Merative MarketScan database (2017–2022). Patients with commercial insurance who received CAR-T therapy (identified by CPT codes) in an inpatient setting for diffuse large B-cell lymphoma (DLBCL), primary mediastinal large B-cell lymphoma (PMBCL), follicular lymphoma (FL), mantle cell lymphoma (MCL), or acute lymphoblastic leukemia (ALL) were included. Patients were followed until disenrollment or the end of 2022 and had at least six months of continuous enrollment before the index date (CAR-T administration date). Infection-related hospitalization was defined as hospital admission due to infection post-CAR-T therapy. Infections were identified using ICD-10 codes and reported as percentages. ED visits due to infections were also analyzed.

Results: Of the 10,024 patients with hematologic malignancies, 246 met the inclusion criteria, with a mean age of 53.2 years (SD: 10.7) and 69.9% being male. A total of 23 (9.35%) patients were hospitalized due to infections following CAR-T therapy, with pneumonia (43.49%) being the most common cause, followed by mycoses (26.1%), cellulitis and abscesses (13.05%), enterocolitis due to Clostridium difficile (4.35%), rotaviral enteritis (4.35%), sinusitis (4.35%), and other local skin and subcutaneous infections (4.35%). The median length of hospitalization was 6 days (IQR: 3–13). Among hospitalized patients, 13.04% were admitted within 30 days, 13.04% between 30–90 days, and 73.91% more than 90 days after CAR-T therapy. Additionally, six patients had ED visits due to infections post-CAR-T therapy.

Conclusions: Infections remain a significant cause of hospitalization following CAR-T therapy, with pneumonia being the most common. The majority of infection-related hospitalizations occurred more than 90 days post-therapy, emphasizing the need for long-term infection monitoring and preventive strategies in this population.