In L-MIND, neutropenia was the most common all-grade AE at 1-year follow-up (median follow-up: 13.2 months), occurring in 49% of patients, and the most common grade ≥3 AE, occurring in 48% of patients.9 Neutropenia was managed with granulocyte colony stimulating factor (G-CSF) in 44% of patients, the majority of whom recovered to baseline neutrophil counts within 1 week.9 Here, CSF3 is linked to neutropenia.