tin-mesoporphyrin and Infant--Premature--Diseases

Sn-mesoporphyrin (SnMP) is a potent inhibitor of bilirubin production. In our previous studies a single dose (6 mumol/kg birth weight) significantly moderated hyperbilirubinemia and reduced phototherapy (PT) time by > 75% when administered within 24 hours of birth to preterm infants.. To directly compare the efficacy of SnMP and PT for controlling hyperbilirubinemia in term and near-term infants.. Two randomized, sequentially analyzed trials (Study I: male term infants; Study II: infants of both sexes and gestational age [GA] 245-265 days) were conducted. SnMP (6 mumol/kg birth weight) or PT (Phillips F20T12/BB lamps) was administered to paired infants according to strict criteria of plasma bilirubin levels and age. Time of enrollment and closure of cases and crossover, if necessary, of SnMP infants to PT or all infants to exchange transfusion were precisely defined in each pair. SnMP or PT was considered superior if the time between enrollment and closure of the case was reduced by > 24 hours over the alternative treatment or if crossover had occurred.. None of the 44 SnMP-treated infants required supplemental PT. Of the 22 pairs of term infants enrolled in Study I, SnMP proved superior to PT in 20 and equal in two. Of the 20 pairs of near-term infants enrolled in Study II, SnMP was superior in 12 and PT in two; six were tied. Two SnMP-treated infants were unpaired. The PT-treated infants in Study I required an average of 33 hours of treatment; those in Study II, 48 hours. None of the enrolled infants required exchange transfusion or interruption of breast-feeding. In both studies, times between case enrollment and closure were reduced by > 30 hours in SnMP compared with PT infants; requirements for additional days of medical observation and bilirubin measurements were also significantly less in SnMP infants.. A single dose of SnMP entirely supplanted the need for PT in jaundiced term and near-term newborns and significantly reduced medical resource use to monitor hyperbilirubinemia.

Topics: Female; Gestational Age; Heme Oxygenase (Decyclizing); Humans; Infant, Newborn; Infant, Premature; Infant, Premature, Diseases; Jaundice, Neonatal; Male; Metalloporphyrins; Phototherapy; Treatment Outcome

Studies in vitro, in animal models, and in adult and newborn humans have demonstrated that certain tin(Sn)-porphyrins that competitively inhibit the activity of heme oxygenase, the rate-limiting enzyme in heme catabolism, reduce production of bilirubin and can thereby substantially diminish plasma levels of the bile pigment.. To assess the effectiveness of increasing doses of the heme oxygenase inhibitor, Sn-mesoporphyrin (SnMP), in moderating the development of significant hyperbilirubinemia and thus the requirements for phototherapy in preterm newborns.. In five randomized, blinded, placebo-controlled trials, SnMP in increasing doses from 1 mumol to 6 mumol/kg body weight was administered intramuscularly in the first 24 hours of life in preterm newborns of 210 to 251 days gestational age. "Special blue" lamps (Phillips F20T12/BB) were used for phototherapy in newborns exceeding a predetermined plasma bilirubin concentration, irrespective of study group.. A total of 517 newborns were randomized in the five trials carried out sequentially over a 4-year period. SnMP in a dose-related manner significantly ameliorated the course of hyperbilirubinemia in the treated newborns of all gestational ages. With a SnMP dose of 6 mumol/kg body weight, the mean peak incremental plasma bilirubin concentration was reduced by 41% and the phototherapy requirements were decreased by 76% compared to control subjects. Erythema observed in a few SnMP-treated newborns who required phototherapy was mild, transient, and without sequelae. No other untoward effects were observed during hospitalization or at a follow-up at post-term age of 3 and 18 months.. SnMP, by inhibiting the production of bilirubin, substantially moderates the development of hyperbilirubinemia in preterm newborns. This compound and similarly acting enzyme inhibitors merit further clinical study as agents for controlling neonatal hyperbilirubinemia, particularly in neonatal populations for whom other treatment modalities are not available.

Topics: Bilirubin; Dose-Response Relationship, Drug; Gestational Age; Heme Oxygenase (Decyclizing); Humans; Infant, Newborn; Infant, Premature, Diseases; Jaundice, Neonatal; Metalloporphyrins; Phototherapy