Monitoring for the Late-Phase Toxicities of CAR T for B-Cell Lymphomas

Dr Friedman outlines common long-term toxicities observed in community practice, with hypogammaglobulinemia being nearly universal, requiring intravenous immunoglobulin replacement for IgG levels below 400. Persistent cytopenias represent a more complex challenge, with patients potentially requiring granulocyte colony stimulating factors or thrombopoietin receptor agonists. The progression and resolution timeline for cytopenias varies, and persistent cases may necessitate bone marrow evaluation to exclude secondary malignancies like myelodysplastic syndromes, particularly given patients' extensive prior chemotherapy exposure.

Standard prophylactic measures include pneumocystis pneumonia (PJP) and herpes simplex virus prophylaxis for at least 6 months, with CD4 monitoring especially important at the 6-month mark. Dr Friedman expresses uncertainty about managing patients with vague symptoms like cognitive changes or general malaise, questioning whether community providers should routinely monitor inflammatory markers like IL-6 levels or when to consider early imaging for disease assessment.

Dr Jacobson emphasizes that protracted or delayed cytokine release syndrome/neurologic toxicity is extremely rare beyond the acute window. For patients presenting with confusion or memory issues weeks after treatment, clinicians should consider opportunistic infections including PJP, cytomegalovirus and human herpesvirus 6, particularly in T-cell lymphopenic patients. She advocates for a "phone a friend" approach, encouraging community oncologists to consult with CAR T centers whenever uncertainty arises about patient symptoms or management decisions, promoting collaborative care to optimize patient outcomes.