Control of severe hyperbilirubinemia in full-term newborns with the inhibitor of bilirubin production Sn-mesoporphyrin

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 greater than or equal to 256.5 mu mol/L and less than or equal to 307.8 mu mol/L (greater than or equal to 15 mg/dL and less than or equal to 18 mg/dL, respectively) that were reached between greater than or equal to 48 and less than or equal to 96 hours of age; b) diminishing the time required for the PBC to decline to less than or equal to 222.3 mu mol/L (less than or equal to 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 greater than or equal to 256.5 mu mol/L and less than or equal to 307.8 mu mol/L (greater than or equal to 15 mg/dL and less than or equal to 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 mu mol/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 less than or equal to 222.3 mu mol/L [13 mg/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 mu mol/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 mu mol/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.