Rapid Peak Cilta-cel Expansion is Associated with Delayed Neurotoxicity in Multiple Myeloma

The authors investigate the relationship between chimeric antigen receptor (CAR)-T cell expansion and the associated clinical outcomes and toxicities in patients with relapsed/refractory multiple myeloma treated with cilta-cel or ide-cel. They find that while cilta-cel leads to greater CAR-T cell expansion, this rapid expansion correlates with an increased risk of delayed neurotoxicities, particularly Parkinsonism, unlike ide-cel, where expansion is linked to clinical response. The study also identifies absolute lymphocyte count as a practical biomarker for predicting neurotoxicity risk, providing thresholds for early identification of at-risk patients.