Control of Severe Hyperbilirubinemia in Full-term Newborns With the Inhibitor of Bilirubin Production Sn-Mesoporphyrin

Abstract

Objective. To assess the efficacy of Sn-mesoporphyrin (SnMP), a potent inhibitor of bilirubin production, in: a) moderating the need for phototherapy (PT) in full-term breastfed infants with plasma bilirubin concentrations (PBC) of ≥256.5 μmol/L and ≤307.8 μmol/L (≥15 mg/dL and ≤18 mg/dL, respectively) that were reached between ≥48 and ≤96 hours of age; b) diminishing the time required for the PBC to decline to ≤222.3 μmol/L (≤13 mg/dL) (closure of the case); c) decreasing the number of bilirubin determinations required for monitoring hyperbilirubinemia. Study Participants. Healthy full-term breastfed infants with a PBC between ≥256.5 μmol/L and ≤307.8 μmol/L (≥15 mg/dL and ≤18 mg/dL, respectively) reached between 48 to 96 hours of age. Design/Methods. After obtaining informed consent from the parents, infants were randomized to either the SnMP (6.0 μmol/kg birth weight, single dose, intramuscular) group or the control group. The infants' PBCs were followed by daily measurements either in the hospital or at discharge as outpatients until the hyperbilirubinemia had subsided (PBC ≤222.3 μmol/L [13mg/dL]). The total number of newborns enrolled in the study was 84; the SnMP group comprised 40 infants; the control group comprised 44 infants. The groups were similar in sex ratio, birth weight, gestational age, PBC, and age at enrollment. All infants were breastfed. Phototherapy was initiated at a PBC of 333.5 μmol/dL (19.5 mg/dL). Results. SnMP entirely eliminated the need for supplemental PT to control hyperbilirubinemia; in contrast, of the 44 control infants, 12 required treatment with PT (27%) when their PBC reached or exceeded the level (333.5 μmol/dL; 19.5 mg/dL) at which time the use of PT was dictated by hospital guidelines. None of the 40 SnMP-treated infants reached a PBC of 19.5 mg/dL. SnMP also markedly diminished the median hours to case closure (SnMP: median, 86.5 hours; minimum/maximum, 24/216 hours; controls: median, 120 hours; minimum/maximum, 72/336 hours); and significantly reduced the number of bilirubin determinations required for clinical monitoring of the infants (SnMP: median, 3; minimum/maximum, 1/9; controls: median, 5; minimum/maximum, 3/11). No adverse effects of SnMP use were observed. Conclusion. A single dose of SnMP proved effective in controlling severe hyperbilirubinemia in full-term breastfed newborns with high bilirubin levels between 48 and 96 hours. In addition, SnMP eliminated the need for PT and reduced the use of medical resources in the clinical treatment of this problem as well as the related, important and painful, emotional costs for both mothers and infants.