A randomized, controlled trial of prophylactic granulocyte-macrophage colony-stimulating factor in human newborns less than 32 weeks gestation

Objective. Preterm neonates undergoing intensive care have high morbidity from sepsis. These infants also frequently develop neutropenia, and when this is associated with sepsis, mortality is high. This study investigates the potential for granulocyte-macrophage colony-stimulating factor (GM-CSF) to effect a clinically relevant increase in neutrophil number when used prophylactically in high-risk preterm neonates, and assesses its safety in this population. Design. In an open, randomized, controlled study, 75 neonates (25 small for gestational age) <32 weeks gestation were randomized to receive GM-CSF (10 mu g/kg/d) by subcutaneous injection for 5 days from <72 hours after birth, or to a control group. The primary outcome measure was the neutrophil count during 14 days from study entry. The infants were monitored for potential toxicity. Clinical outcomes, sepsis, and mortality, were recorded, but this initial study was not designed to address clinical benefit. Results. Prophylactic GM-CSF therapy completely abolished neutropenia in treated infants, when both well and septic, throughout the period of study. Neutropenia (less than or equal to 1.7 x 10(9)/L) developed in 16 of 39 control infants. Five control infants experienced an acute decrease in neutrophil count coincident with the onset of sepsis. There was no evidence of hematologic, respiratory, or gastrointestinal toxicity in treated infants. Treated infants had a trend to fewer symptomatic, blood culture positive septic episodes than controls during 2 weeks from study entry (11/36 vs 18/39). Conclusion. Five-day prophylactic GM-CSF completely abolishes postnatal neutropenia and sepsis-induced neutropenia in preterm neonates at high risk of sepsis, and so removes an important risk factor for sepsis and sepsis-related mortality.