A PILOT-STUDY OF LOW-DOSE RECOMBINANT HUMAN GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR IN CHRONIC NEUTROPENIA

Recombinant human granulocyte macrophage colony stimulating factor (rh GM-CSF) is under investigation for the treatment of a wide range of ha ematological disorders. At commonly used doses of > 120 mug/m2/d, extr amedullary 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 w ith a mean pre-treatment neutrophil count of 0.6 x 10(9)/l (range 0.2- 1.4 x 10(9)/l) received daily rhGM-CSF at doses of between 5 and 15 mu g/m2. Eight patients responded with a mean post-treatment ANC of 3.2 x 10(9)/l (range 1.9-4.6 x 10(9)/l). There was no significant therapy-r elated morbidity. We conclude that in chronic neutropenia, LD rhGM-CSF is an acceptable treatment which has important cost/benefit implicati ons.