Growth Factor in the Setting of CAR T-Cell Therapy: To Use or Not to Use

Patients undergoing chimeric antigen receptor (CAR) T-cell therapy may experience side effects including cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), neutropenia, and infection. Growth factor has historically been used to treat neutropenia; however, its role in CAR T-cell therapy is not well explained. Existing data on the safety and efficacy of growth factor are conflicting. The purpose of this integrative review was to explore the safety and efficacy of growth factor in adult patients with hematologic malignancies undergoing CAR T-cell therapy. A literature review was conducted using PubMed, Cumulative Index to Nursing & Allied Health (CINAHL), and Scopus databases. A total of 2,635 articles were retrieved. Four studies were included that looked at the use of growth factor in the CAR T-cell setting. Safety outcomes evaluated included CRS, ICANS, neutropenic fever and/or infection, and neutropenia duration. Efficacy outcomes evaluated included CAR T-cell expansion and treatment response. The literature suggests that growth factor may not increase CRS prevalence, but may lead to an increased grade of CRS, namely grade 2. Growth factor administration does not have any association with ICANS toxicity, CAR T-cell expansion, or treatment response. Its use may not necessarily lead to decreased infection rates but may shorten the duration of neutropenia. Practice implications for providers working with this unique patient population include using growth factor early in the course of CAR T-cell therapy as treatment to shorten the duration of neutropenia rather than infection prophylaxis.