Growth hormone treatment of non-growth hormone-deficient growth disorders

Clinical Practice Pattern of Korean Medicine Doctors in Idiopathic Short Stature Treatment: A Survey Study

Background

Korean medicine (KM) interventions are attractive for children with idiopathic short stature (ISS). We investigated the real-world clinical practice patterns of KM doctors in ISS treatment.

Methods

The survey targeted KM doctors who have treated patients with ISS in KM clinical settings for >3 years. We included questions on the diagnosis and treatment patterns, effects, cost, and opinions of doctors on KM treatment for ISS. A frequency analysis was performed.

Results

There were 58 respondents, and “heights of parents” (n = 57, 98.3%), “height, weight, and growth rate of child” (n = 55, 94.8%), and “amount of meals, digestive function” (n = 52, 89.7%) were frequently used as indicators for diagnosis and treatment. The most frequently used KM interventions were “herbal medicine” (n = 58, 100%), “acupuncture” (n = 49, 84.5%), “moxibustion” (n = 38, 65.5%), “dry cupping” (n = 26, 44.8%), and “physiotherapy” (n = 22, 37.9%). Herbal medicines were generally prescribed to tonify the spleen or kidney, and the most frequently used individual herbs were Acanthopanacis cortex, Astragali Radix, and Cervi parvum cornu. The most common acupuncture points were ST36, GB34, SP6, EX-LE5, and LI4.

Conclusions

This study showed the use of KM for ISS in real-world clinical settings. In the future, well-designed clinical studies to verify the effect of KM treatment on ISS based on real-world clinical practice patterns should be actively performed.

Evolution and Future of Growth Plate Therapeutics

BACKGROUND

Longitudinal bone growth is regulated by multiple endocrine signals (e.g., growth hormone, insulin-like growth factor I, estrogen, and androgen) and local factors (e.g., fibroblast growth factors and their receptors and the C-natriuretic peptide/natriuretic peptide receptor-B pathway).

SUMMARY

Abnormalities in both endocrine and local regulation of growth plate physiology cause many disorders of human skeletal growth. Knowledge of these pathways creates therapeutic potential for sustaining or even augmenting linear growth. Key Message: During the past 4 decades, advances in understanding growth plate physiology have been accompanied by development and implementation of growth-promoting treatments that have progressed in both efficacy and specificity of action. This paper reviews the history and continuing evolution of growth plate therapeutics.

Height Gain and Safety Outcomes in Growth Hormone-Treated Children with Idiopathic Short Stature: Experience from a Prospective Observational Study

BACKGROUND/OBJECTIVES

Growth hormone (GH) treatment of idiopathic short stature (ISS) received US Food and Drug Administration approval in 2003. We assessed height gain and safety in 2,450 children with ISS treated with GH in US clinical practice.

METHODS

Short-term height gain, near-adult height (NAH), and safety outcomes were investigated using Genetics and Neuroendocrinology of Short Stature International Study data.

RESULTS

Compared to children with isolated idiopathic GH deficiency (IGHD), those with ISS were shorter at baseline but had similar age and GH dose. Mean ± SD height SD score (SDS) increase was similar for ISS and IGHD, with 0.6 ± 0.3 (first), 0.4 ± 0.3 (second), 0.3 ± 0.3 (third), and 0.1 ± 0.3 (fourth year) for ISS. Girls with ISS (27% of subjects) were younger and shorter than boys but had similar height gain over time. At NAH in the ISS group (n = 467), mean ± SD age, GH duration, and height SDS were 17.3 ± 2.3 years, 4.6 ± 2.7 years, and -1.2 ± 0.9, respectively. Height gain from baseline was 1.1 ± 1.0 SDS and was greater for boys than girls (1.2 ± 1.0 vs. 0.9 ± 0.9), but boys were treated longer (5.1 ± 2.8 vs. 3.6 ± 2.5 years). Adverse events were reported for 24% with ISS versus 20% with IGHD - most were common childhood conditions or previously reported in GH-treated patients.

CONCLUSIONS

GH-treated children with ISS achieved substantial height gain, similar to patients with IGHD. Fewer GH-treated girls were enrolled than boys, but with similar height SDS gain over time. No ISS-specific safety issues were identified. Thus, GH treatment of ISS appears to have a safety/effectiveness profile similar to that of IGHD.

Genetic Polymorphisms Associated with Idiopathic Short Stature and First-Year Response to Growth Hormone Treatment

BACKGROUND/AIMS

The term idiopathic short stature (ISS) describes short stature of unknown, but likely polygenic, etiology. This study aimed to identify genetic polymorphisms associated with the ISS phenotype, and with growth response to supplemental GH.

METHODS

Using a case-control analysis we compared the prevalence of "tall" versus "short" alleles at 52 polymorphic loci (17 in growth-related candidate genes, 35 identified in prior genome-wide association studies of adult height) in 94 children with ISS followed in the Genetics and Neuroendocrinology of Short Stature International Study, versus 143 controls from the Fels Longitudinal Study.

RESULTS

Four variants were nominally associated with ISS using a genotypic model, confirmed by a simultaneous confident inference approach: compared with controls children with ISS had lower odds of "tall" alleles (odds ratio, 95% CI) for GHR (0.52, 0.29-0.96); rs2234693/ESR1 (0.50, 0.25-0.98); rs967417/BMP2 (0.39, 0.17-0.93), and rs4743034/ZNF462 (0.40, 0.18-0.89). Children with ISS also had lower odds of the "tall" allele (A) at the IGFBP3 -202 promoter polymorphism (rs2855744; 0.40, 0.20-0.80) in the simultaneous confident inference analysis. A significant association with 1st-year height SD score increase during GH treatment was observed with rs11205277, located near 4 known genes: MTMR11, SV2A, HIST2H2AA3, and SF3B4; the latter, in which heterozygous mutations occur in Nager acrofacial dysostosis, appears the most relevant gene.

CONCLUSIONS

In children with ISS we identified associations with "short" alleles at a number of height-related loci. In addition, a polymorphic variant located near SF3B4 was associated with the GH treatment response in our cohort. The findings in our small study warrant further investigation.

Effect of Growth Hormone Therapy on Height Velocity in Korean Children with Idiopathic Short Stature: A Phase III Randomised Controlled Trial

BACKGROUND/AIMS

The SYNERGY (Saizen® for Your New Life and Brighter Tomorrow without Growth Deficiency) study is the first randomised multi-centre, open-label study to assess the short-term efficacy and safety of this recombinant human growth hormone (r-hGH) preparation for prepubertal children with idiopathic short stature in South Korea.

METHODS

The SYNERGY study (ClinicalTrials.gov NCT01746862) was conducted at 9 centres throughout South Korea between December 2012 and March 2015. The primary endpoint was difference in height velocity from baseline to 6 months in the treatment and control arms.

RESULTS

97 children were screened; 90 were randomly assigned: 60 children to 0.067 mg/kg/day r-hGH for 12 months (treatment) and 30 children to 6 months of no treatment followed by 0.067 mg/kg/day r-hGH for 6 months (control). The 6-month mean height velocity in the treatment group increased from 5.63 cm/year (SD 1.62) to 10.08 cm/year (SD 1.92) (p < 0.0001) and from 4.94 cm/year (SD 1.91) to 5.92 cm/year (SD 2.01) (p = 0.0938) in the control group (between-group difference 3.47 cm/year, 95% CI 2.17-4.78; p < 0.0001). Adherence was > 90% throughout the study. The safety profile was consistent with that already known for r-hGH.

CONCLUSION

Treatment with r-hGH in the SYNERGY study demonstrated a statistically significant increase in height velocity at 6 months.

Efficacy of short-term growth hormone treatment in prepubertal children with idiopathic short stature

PURPOSE

It has been reported that daily recombinant human growth hormone (GH) treatment showed beneficial effects on growth in prepubertal children with idiopathic short stature (ISS). The present study aimed to validate the GH (Eutropin®) effect on growth promotion and safety after short-term GH treatment.

MATERIALS AND METHODS

This study was an open-label, multicenter, interventional study conducted at nine university hospitals in Korea between 2008 and 2009. Thirty six prepubertal children with ISS were enrolled in this study to receive 6-month GH treatment. Yearly growth rate, height standard deviation score (SDS), and adverse events were investigated during treatment.

RESULTS

After 26 weeks of GH treatment, the height velocity significantly increased by 6.36±3.36 cm/year (p<0.001). The lower end of one-sided 95% confidence interval was 5.22 cm/year, far greater than the predefined effect size. The gain in height SDS at week 26 was 0.57±0.27 (p<0.0001). Bone age significantly increased after GH treatment, however, bone maturation rate (bone age for chronological age) showed limited advancement. This 26-week GH treatment was effective in increasing serum levels of insulin-like growth factor (IGF)-I and IGF binding protein (IGFBP)-3 from baseline (p<0.0001). Eutropin was well tolerated and there were no withdrawals due to adverse events. No clinically significant changes in laboratory values were observed.

CONCLUSION

This 6-month daily GH treatment in children with ISS demonstrated increased height velocity, improved height SDS, and increased IGF-I and IGFBP-3 levels with a favorable safety profile.

Update on Turner and Noonan syndromes

Turner syndrome (TS) and Noonan syndrome (NS) have short stature as a constant feature; however, both conditions can present clinicians with a challenging array of genetic, cardiovascular, developmental, and psychosocial issues. In recent years, important advances have been achieved in each of these areas. This article reviews these two syndromes and provides updates on recent developments in diagnostic evaluation, growth and development, psychological issues, and treatment options for patients with TS and NS.

A mathematical model in the analysis of the response to growth hormone treatment in pediatric patients with diagnosis of growth hormone deficiency

In the literature, few studies analyze the effect of GH therapy on height, preferring a more indirect approach, where factors influencing the total pubertal and pre-pubertal growth in GH-deficient patients are evaluated and subsequently used to estimate the overall effect at the end of the therapy; unfortunately, this approach does not quantify the real growth gain in treated patients. Using a non-parametric Empirical Bayes approach, our study analyzes the growth response to GH treatment in a homogeneous cohort of 317 patients with pituitary GH deficiency who were enrolled during their pre-pubertal stage in the GH Piedmont Registry (Italy), between January 2000-October 2008, and have at least 2 yr of follow-up. To estimate the growth curve for males and females, a non-parametric regression model was fitted, applying Empirical Bayes techniques. A validation of the model was also performed. Improvement was evident in both genders, since both males and females mean growth curve, which started below the 3rd percentile at the beginning of the therapy, reached the 10th percentile of the Tanner curve at the end of observation (17 yr old for males and 14 yr old for females); the estimation procedure achieved a good precision. The methodological approach allows for fitting a model able to evaluate longitudinally the response to GH treatment, by means of estimating the overall growth curve, even in presence of sparse information about children heights.

Protein glycoengineering enabled by the versatile synthesis of aminooxy glycans and the genetically encoded aldehyde tag

Homogeneously glycosylated proteins are important targets for fundamental research and for biopharmaceutical development. The use of unnatural protein–glycan linkages bearing structural similarity to their native counterparts can accelerate the synthesis of glycoengineered proteins. Here we report an approach toward generating homogeneously glycosylated proteins that involves chemical attachment of aminooxy glycans to recombinantly produced proteins via oxime linkages. We employed the recently introduced aldehyde tag method to obtain a recombinant protein with the aldehyde-bearing formylglycine residue at a specific site. Complex aminooxy glycans were synthesized using a new route that features N-pentenoyl hydroxamates as key intermediates that can be readily elaborated chemically and enzymatically. We demonstrated the method by constructing site-specifically glycosylated variants of the human growth hormone.

N-glycosylation increases the circulatory half-life of human growth hormone

Therapeutic use of recombinant GH typically involves daily sc injections. We examined the possibilities for prolonging the in vivo circulation of GH by introducing N-glycans. Human GH variants with a single potential N-glycosylation site (N-X-S/T) introduced by site-directed mutagenesis were expressed in HEK293 cells. In a scan of 15 different positions for N-glycosylation sites, four positions (amino acids 93, 98, 99, and 101) were efficiently utilized and did not influence GH in vitro activity. A GH variant (3N-GH) with all these sites was produced in CHOK1SV cells and contained up to three N-glycans. Two pools of 3N-GH were purified and separated according to their charge by anion-exchange chromatography. Anion-exchange HPLC revealed that the N-glycans in the two pools were very similar except for the extent of sialylation. Both 3N-GH pools circulated longer in rats than wild-type GH. The terminal half-life of 3N-GH after iv injection was 24-fold prolonged compared with wild-type GH for the pool with the most pronounced sialylation, 13-fold prolonged for the less sialylated pool, and similar to the wild-type for desialylated 3N-GH. The less sialylated 3N-GH pool exhibited a profound pharmacodynamic effect in GH-deficient rats. Over a 4-d period, a single injection of 3N-GH induced a stronger IGF-I response and a larger increase in body weight than daily injections with wild-type GH. Thus, N-glycans can prolong the in vivo circulation and enhance the pharmacodynamic effect of GH. Sialic acids seem to play a pivotal role for the properties of glycosylated GH.

Human growth hormone expressed in tobacco cells as an arabinogalactan-protein fusion glycoprotein has a prolonged serum life

Therapeutic proteins with molecular weights lower than 40 kDa often have short serum half-lives due to their susceptibility to serum proteases and rapid renal clearance. Chemical derivatization, such as PEGylation, or expression as serum albumin fusions increases molecular mass and overcome these problems but at the expense of decreased bioactivity. Here we applied a new method that yields biologically potent recombinant human growth hormone (rhGH) with increased serum half-life when expressed as an arabinogalactan-protein (AGP) in tobacco BY-2 cells. Thus, rhGH was expressed with 10 repeats of the AGP glycomodule Ser-Hyp (SO) at the C-terminus (rhGH-(SO)(10)). We also expressed rhGH as an AGP-enhanced green fluorescent protein (EGFP) fusion, designated rhGH-(SO)(10)-EGFP, to assess the cellular distribution of the glycoprotein, which was mainly extracellular. Recombinant hGH-(SO)(10) bound the hGH receptor with an affinity similar to that of a rhGH standard, stimulated the same intracellular signaling pathway as hGH, but possessed an in vivo serum half-life more than sixfold that of the hGH control. Furthermore, rhGH-(SO)(10) gave a 500 fold greater secreted yield than the non-glycosylated control rhGH that was also targeted for secretion. Detailed analysis of the rhGH-(SO)(10) glycans indicated a conserved structure with relatively little microheterogeneity and an average size of 25 monosaccharide residues. These results were consistent with earlier work expressing interferon alpha 2b as an AGP chimera and further demonstrate the feasibility of this approach to the production of long-acting, biologically potent therapeutic proteins by plant cells.

Response to growth hormone therapy in Indian patients

OBJECTIVE

To analyse response to growth hormone therapy on Indian patients with short stature.

METHODS

Data were collected on 71 patients of short stature on GHT. All patients underwent clinical and hormonal evaluation. GHD was diagnosed in the presence of short stature (height SDS < 2) and peak GH levels < 10 ng/ml. Bone age was estimated using Tanner Whitehouse 3 method (TW3).

RESULTS

Primary GHD (73%) was the commonest diagnosis among patients on GHT, followed by organic GHD (12.6%), genetic syndromes (8.4%) and systemic diseases (5.4%). Mean chronological age at presentation was 10.07+/-3.26 years (median-11 years, range 3-15 years), mean height age was 6.98+/-2.82 years (median 7.5 years, range 1-13 years) and mean bone age (available for 55 patients) was 7.19+/-3.1 years (median 8.2 years, range 1.3-13 years). Patients with systemic diseases (6.75+/-3.5 years) presented earlier, compared to patients with GHD (10.27+/-3.16 years) and genetic syndromes (10.18+/-3.20 years) (p=0.349). Most of the patients on GHT were in the age group 9-15 years (60.6%). Mean height gain with GHT was 8.7+/-2.7 cm (median 8.3 cm, range 3.0-13 cm) during 1st year then decreased to 6.9+/-2.4 cm (median 7.0 cm, range 3.0-12.5 cm) in the second year, and was maintained through the third year (mean 7.1+/-3.0 cm, median 7.0, range 3.0-13 cm). Among patients with GHD, those with primary deficiency had significantly better response to GHT in 1st year than secondary deficiency (9.0+/-2.65 vs 6.8+/-3.03 cm, p = 0.026). Response to GHT was negatively correlated with CA (r-0.27, p = 0.05), HA (r-0.47, p = 0.027) and BA (r-0.31, p=0.022) at presentation. Four patients (5.6%) developed hypothyroidism and one patient each developed disseminated tuberculosis and rickets. One patient of Turner's syndrome died of adrenal carcinoma. Short follow up and absence of measurement of IGF-1 and IGFBP3 were major limitations of this study.

CONCLUSIONS

Response to GHT in Indian patients is comparable to western counterparts. Maximum height gain on GHT is during the first year than decreases in second year, but is maintained through third year. Patients with primary GHD had better response than secondary GHD. Response to GHT is negatively correlated with chronological, height and bone age at presentation.

Monosomy for the X chromosome

Dosage compensation serves to equalize X chromosome gene expression in mammalian males and females and involves extensive silencing of the 2nd X chromosome in females. If dosage compensation mechanisms completely suppressed the 2nd X chromosome, then actual physical loss of this "eXtra" chromosome should have few consequences. However, X monosomy has major effects upon normal development, fertility and longevity in humans and some other species. This article reviews observations and arguments attempting to explain the phenotypic effects of X monosomy in humans and other mammals in terms of X chromosome gene dosage.

[GH treatment in patients with idiopathic short stature]

Growth hormone has been used in the treatment of patients with idiopathic short stature. Clinical and laboratory criteria are discussed, taking into consideration the indication of GH and the evaluation of its efficacy and individual responsiveness. Anthropometric, psychosocial, ethical, and also cost/benefit aspects must be considered before GH prescription in idiopathic short stature patients.

Growth hormone and the adolescent athlete: What are the data for its safety and efficacy as an ergogenic agent?

There is great interest among athletes and in the sports and general media for the subject of "doping" with human growth hormone (hGH). The hype about this substance goes far beyond the available data. The issue of administration of recombinant rhGH to adolescents, whether for athletic performance or for esthetic purposes adds another wrinkle because normal pubertal growth and the acquisition of adult body composition depends upon the GH/IGF-I and the hypothalamic-pituitary-gonadal axes. The range of normal is wide and it is more difficult to determine the natural evolution of pubertal development from that fueled by rhGH (or anabolic steroids). There are no compelling data based on clinical trials to indicate enhanced athletic performance (young adults); however, one cannot be sure how rhGH is used in combination with other agents, including anabolic steroids and anabolic "supplements". There are no studies in adolescent athletes. The detection of administration of rhGH to adolescents using the analytes of the GH/IGF-I and of collagen turnover (bone modeling and remodeling) is complicated by the physiologic increases in these parameters during normal puberty. It should be noted that many older adolescents are physiologically younger, especially in those aesthetic sports that demand the thin (linear) physique.

Idiopathic short stature: management and growth hormone treatment

In the management of ISS auxological, biochemical, psychosocial and ethical elements have to be considered. In boys with constitutional delay of growth and puberty androgens are effective in increasing height and sexual characteristics, but adult height is unchanged. GH therapy is efficacious in increasing height velocity and adult height, but the inter-individual variation is considerable. The effect on psychosocial status is uncertain. Factors affecting final height gain include GH dose, height deficit in comparison to midparental height, age and first year height velocity. In case of a low predicted adult height at the onset of puberty, addition of a GnRH analogue can be considered. Although GH therapy appears safe, long-term monitoring is recommended.