Sarcopenia and Skeletal Muscle Loss after CAR T-cell Therapy in Diffuse Large B cell Lymphoma

Purpose: Sarcopenia is a hallmark of cancer cachexia. Chimeric antigen receptor (CAR) T-cell therapy is associated with an inflammatory state that may exacerbate sarcopenia. The relationship between CAR T-cell therapy, sarcopenia, and metabolism is poorly understood. Experimental Design: In 83 large B-cell lymphoma patients, the skeletal muscle index (SMI) was measured from clinical images obtained at baseline and days 30 and 90 post-therapy. Serum metabolomics (n=57 patients) was performed in the first 4 weeks. Results: Baseline sarcopenia was present in over half of patients and associated with shorter median overall survival (OS) than for non-sarcopenic patients (10.5 versus 34.3 months; P=0.006). This reduction was due to increased non-relapse mortality (NRM) with all six NRM events occurring in patients with baseline sarcopenia. In the first 30 days after CAR T-cell therapy, 1/3 of patients experienced skeletal muscle loss greater than 10%. Muscle loss was associated with higher tumor burden and neurotoxicity but was not significantly associated with long term survival. Serum metabolomics revealed an early (weeks 1-2) increase in purine metabolites, followed by a later (weeks 3-4) increase in triglyceride levels. The serum metabolite with the highest fold-increase from baseline was adipic acid, attributed to the inpatient hospital menu of Jello and other tart beverages. Conclusions: Skeletal muscle loss after CAR T-cell therapy is common and is associated with fatty acid catabolism. Patients with baseline sarcopenia have poor tolerance and reduced survival. Future studies of dietary and exercise interventions may improve CAR T-cell therapy outcomes.