Faculty Bibliography

The term small for gestational age (SGA) refers to infants whose birth weights and/or lengths are at least two standard deviation (SD) units less than the mean for gestational age. This condition affects approximately 3%-10% of newborns. Causes for SGA birth include environmental factors, placental factors such as abnormal uteroplacental blood flow, and inherited genetic mutations. In the past two decades, an enhanced understanding of genetics has identified several potential causes for SGA. These include mutations that affect the growth hormone (GH)/insulin-like growth factor (IGF)-1 axis, including mutations in the IGF-1 gene and acid-labile subunit (ALS) deficiency. In addition, select polymorphisms observed in patients with SGA include those involved in genes associated with obesity, type 2 diabetes, hypertension, ischemic heart disease and deletion of exon 3 growth hormone receptor (d3-GHR) polymorphism. Uniparental disomy (UPD) and imprinting effects may also underlie some of the phenotypes observed in SGA individuals. The variety of genetic mutations associated with SGA births helps explain the diversity of phenotype characteristics, such as impaired motor or mental development, present in individuals with this disorder. Predicting the effectiveness of recombinant human GH (hGH) therapy for each type of mutation remains challenging. Factors affecting response to hGH therapy include the dose and method of hGH administration as well as the age of initiation of hGH therapy. This article reviews the results of these studies and summarizes the success of hGH therapy in treating this difficult and genetically heterogenous disorder.

BACKGROUND:GH treatment currently requires daily sc injections, resulting in suboptimal compliance. A GH regimen with fewer injections may offer patients and caregivers a less arduous option. LB03002 is a novel sustained-release GH formulation for once-weekly dosing. PATIENTS AND METHODS/METHODS:GH-deficient, GH-naive prepubertal children were randomized to four groups who received 0.2 mg/kg/wk LB03002 for 12 months, followed by 0.5 mg/kg/wk for another 24 months (n=13); 0.5 mg/kg/wk LB03002 for 36 months (n=13); 0.7 mg/kg/wk LB03002 for 12 months, followed by 0.5 mg/kg/wk for another 24 months (n=13); or daily GH 0.03 mg/kg/d for 24 months, switched to 0.5 mg/kg/wk LB03002 for 12 months (n = 12). RESULTS:Height velocity increased in all groups; the increase was less for the 0.2 mg/kg/wk LB03002 group at 12 (P = 0.008) and 24 months (P = 0.030), with no statistically significant differences at any time for the 0.5 mg/kg/wk and 0.7 mg/kg/wk LB03002 groups, vs. daily GH. Height sd score gain at 12 months was significantly (P = 0.023) less for the 0.2 mg/kg/wk group (1.05 ± 0.38) than daily GH (1.47 ± 0.29), but with no statistically significant difference for the 0.5 mg/kg/wk (1.37 ± 0.39) and 0.7 mg/kg/wk (1.50 ± 0.44) LB03002 groups vs. daily GH. There were no significant differences in height sd score gain between any groups at 24 and 36 months. Bone maturation did not differ for any LB03002 dose compared with daily GH. Serum IGF-I concentrations increased as expected, with no long-term differences between groups. Mean fasting glucose and glycosylated hemoglobin concentrations did not exceed normal ranges for any treatment group at any time. CONCLUSION/CONCLUSIONS:LB03002 at doses of 0.5 mg/kg/wk and 0.7 mg/kg/wk was shown to be effective and safe with once-weekly dosing in GH-deficient children, and 0.5 mg/kg/wk LB03002 was chosen as the optimal dose for long-term assessment.

As the first wave of biopharmaceuticals is expiring, biosimilars or follow-on -protein products (FOPP's) have emerged. Biosimilar drugs are cheaper than the originator/comparator drug. The regulatory foundation for these products is more advanced and better codified in Europe than in the US. Biosimilar soamtropin has been approved in both the US and Europe. The scientific viability of biosimilar drugs and especially growth hormone has been proven by several rigorously conducted clinical trials. Efficacy and safety data (growth rates, IGF-1 generation) for up to 7 y for pediatric indications measure up favorably to previously approved growth hormones which served as reference comparators. The Obama Administration appears to be committed to establish innovative pathways for the approval of biologics and biosimilars in the US. The cost savings in health care expenditures will be substantial as the global sales of biologics have reached $ 93 billion in 2009.

OBJECTIVE:Two strengths of a novel ready-to-use liquid preparation of the recombinant human GH (rhGH) Omnitrope were developed to increase the convenience for the patients. DESIGN/METHODS:Omnitrope 3.3 mg/ml solution or Omnitrope 6.7 mg/ml solution was compared to Omnitrope 5 mg/ml powder and Genotropin 5 mg/ml powder in terms of pharmacokinetics, pharmacodynamics, safety, and local tolerance after a single s.c. dose of 5 mg. METHODS:Two randomized, double-blind, single-dose, three-way crossover studies were carried out in 36 young healthy volunteers each. Endogenous GH secretion was suppressed with a 25-h continuous i.v. infusion of octreotide (40 microg/h) starting 1 h before rhGH administration. RESULTS:Pharmacokinetic parameters were similar for the three treatments in both studies respectively. Bioequivalence criteria were met for area under the concentration-time curve (AUC) and C(max). Likewise, the pharmacodynamic parameters for IGF1, IGF-binding protein 3, and non-esterified fatty acid were similar for all preparations. No differences in adverse events were observed between groups. CONCLUSIONS:Omnitrope 3.3 mg/ml solution, 6.7 mg/ml solution, and 5 mg/ml powder, and Genotropin 5 mg/ml powder are bioequivalent, have similar pharmacokinetic and pharmacodynamic profiles, and are equally safe. Overall, the products can be considered to be therapeutically interchangeable.

OBJECTIVE:LB03002 is a novel, sustained-release recombinant human GH, developed for once-a-week s.c. injection. To evaluate the suitability for long-term GH replacement therapy in children with GH deficiency (GHD), the present study assessed the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of LB03002 at three doses. STUDY DESIGN AND PATIENTS/METHODS:The randomised, comparator-controlled, assessor-blinded, phase II study assessed 37 (24 boys, 13 girls) pre-pubertal, GH-naïve children with GHD, in 11 European centres, for PK and PD analyses. GH, IGF1 and IGFBP3 concentrations were measured following the last daily GH dose and the first and 13th once-a-week administration of LB03002 at doses of 0.2, 0.5 or 0.7 mg/kg. RESULTS:GH C(max) values after the three doses of LB03002 were increased up to fourfold, with a clear dose proportionality. For each LB03002 dose, GH area under the concentration versus time curve did not increase from the first to 13th (month 3) administration, indicating no accumulation of circulating GH. IGF1 C(max) showed a progressive increase during LB03002 administration. Conversely, IGFBP3 showed a rapid increase in C(max). IGF1 SDS were fully normalised after 3 months of treatment, whereas IGFBP3 SDS were already in the normal range for all the three LB03002 dosages after 1 week. CONCLUSIONS:At the doses used, LB03002 has a suitable profile for long-term treatment to promote growth in children with GHD. The quantitative changes in IGF1 and IGFBP3 indicate adequate stimulation of the IGF system by LB03002 and the pattern of increase is comparable with that seen in GHD children in a standard IGF1 generation test using daily GH.