A pilot study of low-dose recombinant human granulocyte-macrophage colony-stimulating factor in chronic neutropenia

Summary. Recombinant human granulocyte macrophage colony stimulating factor (rhGM-CSF) is under investigation for the treatment of a wide range of haematological disorders. At commonly used doses of > 120 μg/m2/d, extramedullary toxicity is common. We report the effects of low-dose (LD) rhGM-CSF in patients with chronic neutropenia related to HIV infection, myelodysplastic syndrome and idiopathic neutropenia. Nine patients with a mean pre-treatment neutrophil count of 0·6 × 109/1 (range 0·2–1·4 × 109/1) received daily rhGM-CSF at doses of between 5 and 15 μg/m2, Eight patients responded with a mean post-treatment ANC of 3·2 × 109/1 (range 1·9–4·6 × 109/1). There was no significant therapy-related morbidity. We conclude that in chronic neutropenia, LD rhGM-CSF is an acceptable treatment which has important cost/benefit implications.