Rapid peak cilta-cel expansion is associated with delayed neurotoxicity in multiple myeloma.

Rapid peak cilta-cel expansion is linked to increased risk of delayed neurotoxicity in patients with relapsed/refractory multiple myeloma.

• Why it matters: Understanding how CAR T-cell expansion relates to toxicity is crucial for improving safety and outcomes in multiple myeloma treatment, but standardized measurement methods are limited.
• What they did: Researchers analyzed CAR T-cell kinetics in 90 patients using flow cytometry, finding cilta-cel caused greater expansion than ide-cel, with rapid expansion associated with delayed neurotoxicities, and validated ALC as a surrogate biomarker in 532 patients.
• The result: High peak ALC (≥3×10³/μL) predicted elevated risk of delayed neurotoxicity, especially parkinsonism after cilta-cel, enabling early identification of at-risk patients and informing strategies to reduce morbidity.