Growth hormone: the expansion of available products and indications

Evaluating the TUITEK® patient support program in supporting caregivers of children diagnosed with growth hormone deficiency in Argentina

Introduction

The appropriate use of recombinant human growth hormone (r-hGH) treatment provides an opportunity to improve growth outcomes among pediatric patients with growth hormone deficiency (GHD). However, a major challenge in clinical practice is to adequately recognize and address factors that negatively affect treatment adherence. TUITEK® patient support program (PSP) was designed to help caregivers of children diagnosed with GHD to personalize the care pathway, improve adherence, and achieve better outcomes. Effectiveness of TUITEK® PSP has been demonstrated previously in a smaller sample (n = 31) in Taiwanese population. Here, we present the results from Argentina.

Methods

TUITEK® PSP was piloted among 76 caregivers of children with GHD administering r-hGH using easypod™ (Merck KGaA, Darmstadt, Germany) auto-injector device in Argentina. Based on TUITEK® personalization questionnaire, caregivers were assigned to high- and low-risk groups across four categories that may influence adherence, including disease and treatment coherence (DTC), self-administration (SA), treatment-related anxiety (TRA), and emotional burden (EB). The caregivers who were included in atleast one high-risk group had the provision of telephone calls with a nurse practitioner every 2 weeks for 3 months. The Wilcoxon signed-rank test was employed to assess changes in questionnaire-based scoring patterns between baseline and follow-up evaluations.

Results

Statistically significant changes (p < 0.05) in questionnaire scores between baseline and follow-up evaluations were observed across the four categories. The mean/median DTC (n = 11) and SA (n = 23) scores changed from 2.45/3 and 2.17/2, respectively, to 4/4, with all the caregivers moving to low-risk group following program completion (100%) for both categories. The mean/median TRA score (n = 40) changed from 3.58/3 to 2.5/2 and 67.5% of patients (27/40) moved to low-risk group. The mean/median EB score (n = 32) changed from 3.69/3 to 3.13/3 however, none of the caregivers moved to low-risk group (0%).

Conclusion

TUITEK® PSP is a simple, practical, and time-efficient interventional tool that can be used to address key adherence-related issues among caregivers of children with GHD and provide personalized adherence support. Our findings demonstrate that TUITEK® PSP has the potential to improve treatment adherence and self-management, thereby improving growth outcomes in Argentina.

New insight into the importance of formulation variables on parenteral growth hormone preparations: potential effect on the injection-site pain

Reducing injection-site pain (ISP) in patients with chronic conditions such as growth hormone deficiency is a valuable strategy to improve patient compliance and therapeutic efficiency. Thus understanding different aspects of pain induction following subcutaneous injection of biotherapeutics and identifying the responsible factors are vital. Here we have discussed the effects of formulation's viscosity, concentration, osmolality, buffering agents, pH, and temperature as well as injection volume, dosing frequency, and different excipients on ISP following subcutaneous injection of commercially available recombinant human growth hormone products. Our literature review found limited available data on the effects of different components of parenteral rhGH products on ISP. This may be due to high cost associated with conducting various clinical trials to assess each excipient in the formulation or to determine the complex interactions of different components and its impact on ISP. Recently, conducting molecular dynamics simulation studies before formulation design has been recommended as an alternative and less-expensive approach. On the other hand, the observed inconsistencies in the available data is mainly due to different pain measurement approaches used in each study. Moreover, it is difficult to translate data obtained from animal studies to human subjects. Despite all these limitations, our investigation showed that components of parenteral rhGH products can significantly contribute to ISP. We suggest further investigation is required for development of long acting, buffer-free, preservative-free formulations. Besides, various excipients are currently being investigated for reducing ISP which can be used as alternatives for common buffers, surfactants or preservatives in designing future rhGH formulations.

Investigating the Impact of the TUITEK® Patient Support Programme, Designed to Support Caregivers of Children Prescribed Recombinant Human Growth Hormone Treatment in Taiwan

PURPOSE

Poor adherence to recombinant human growth hormone (r-hGH) treatment presents a significant barrier to achieving optimal growth outcomes. It is important to identify and address the treatment adherence-related needs of children prescribed r-hGH treatment, and develop new approaches to improve adherence. We aimed to measure the impact of the TUITEK^® patient support programme, a multi-component personalized service intervention, on caregivers' knowledge, beliefs, and perceptions of short stature and adherence to its treatment.

PATIENTS AND METHODS

The evaluation of the TUITEK^® patient support programme was conducted among 31 caregivers of children with short stature and receiving r-hGH treatment via the easypod™ auto-injector device in Taiwan. Caregivers within the 'high risk' category for knowledge, beliefs and perception factors influencing adherence to r-hGH treatment (disease and treatment coherence, emotional burden, self-administration, and treatment-related anxiety) were identified via the TUITEK^® personalization questionnaire and followed up with bi-weekly telephone calls by a nurse practitioner over a 3-month period. A Wilcoxon signed-rank test was used to compare changes in questionnaire-based scoring patterns between baseline and follow-up.

RESULTS

Between baseline and follow-up, the percentage of caregivers scoring as 'high risk' for emotional burden reduced by 37%; there was an improvement in confidence of self-administration by 57% and the percentage of caregivers scoring as 'high risk' for treatment-related anxiety reduced by 52%. At follow-up, all caregivers classified as 'high risk' within the disease and treatment coherence item at baseline moved into the 'low risk' category. Statistically significant changes in questionnaire scores between baseline and follow-up for disease and treatment understanding, emotional burden, self-administration, and treatment-related anxiety were also observed.

CONCLUSION

These findings indicate that the TUITEK^® patient support programme can positively address disease and treatment-related barriers amongst caregivers regarding optimal adherence of their children to r-hGH treatment, which has the potential to positively impact on adherence levels and patient clinical health outcomes.

Effectiveness and Overall Safety of NutropinAq® for Growth Hormone Deficiency and Other Paediatric Growth Hormone Disorders: Completion of the International Cooperative Growth Study, NutropinAq® European Registry (iNCGS)

Objective

The International Cooperative Growth Study, NutropinAq® European Registry (iNCGS) (NCT00455728) monitored long-term safety and effectiveness of recombinant human growth hormone (rhGH; NutropinAq® [somatropin]) in paediatric growth disorders.

Methods

Open-label, non-interventional, post-marketing surveillance study recruiting children with growth disorders. Endpoints included gain in height standard deviation score (SDS), adult height, and occurrence of adverse events (AEs).

Results

2792 patients were enrolled. 2082 patients (74.6%) had growth hormone deficiency (GHD), which was isolated idiopathic in 1825 patients (87.7%). Non-GHD diagnoses included Turner syndrome (TS) (n=199), chronic renal insufficiency (CRI) (n=10), other non-GHD (n=498), and missing data for three participants. Improvements from baseline height SDS occurred at all time points to Month 132, and in all subgroups by disease aetiology. At Month 12, mean (95% CI) change in height SDS by aetiology was: idiopathic GHD 0.63 (0.61;0.66), organic GHD 0.71 (0.62;0.80), TS 0.59 (0.53; 0.65), CRI 0.54 (-0.49;1.56), and other non-GHD 0.64 (0.59;0.69). Mean height ( ± SD) at the last visit among the 235 patients with adult or near-adult height recorded was 154.0 cm ( ± 8.0) for girls and 166.7 cm ( ± 8.0) for boys. The most frequent biological and clinical non-serious drug-related AEs were increased insulin-like growth factor concentrations (314 events) and injection site haematoma (99 events). Serious AEs related to rhGH according to investigators were reported (n=30); the most frequent were scoliosis (4 events), epiphysiolysis (3 events), and strabismus (2 events).

Conclusions

There was an improvement in mean height SDS in all aetiology subgroups after rhGH treatment. No new safety concerns were identified.

Changes in Manufacturing Processes of Biologic Therapies Can Alter the Immunogenicity Profile of the Product

Manufacturing process changes may alter the characteristics of a protein therapeutic. In 2009, somatropin (version 1.0), a recombinant human growth hormone therapeutic, underwent a manufacturing update (version 1.1). The immunogenicity of somatropin version 1.1 as a daily subcutaneous injection was evaluated in 2014 in a prospective, open-label, single-arm clinical study of treatment-naive pediatric patients with idiopathic human growth hormone deficiency for 1 year. The primary end point was the proportion of patients who developed antidrug antibodies (ADAs) after treatment. Eighty-two patients were enrolled. The mean (SD) treatment duration was 347 (53) days. The incidence of ADAs was 3.7%. No neutralizing antibodies were observed in the three patients with ADA-positive samples. Two patients (2.6%) had growth attenuation, but they were not ADA positive. The manufacturing changes for somatropin version 1.1 resulted in a similar safety and efficacy profile compared with somatropin version 1.0 and a different immunogenicity profile with a lower incidence of ADAs.

Attention-Deficit/Hyperactivity Disorder Medication Treatment Impact on Response to Growth Hormone Therapy: Results from the ANSWER Program, a Non-Interventional Study

OBJECTIVE

To examine whether attention-deficit/hyperactivity disorder (ADHD) stimulant medication modified the linear growth response to growth hormone (GH) treatment in children enrolled in the American Norditropin Studies: Web-Enabled Research Program.

STUDY DESIGN

Short, GH treatment-naive children with or without GH deficiency (GHD) received GH therapy. A subset also received ADHD stimulant medication (n = 1190), and others did not (n = 7230). Linear mixed models (adjusted means) examined height SDS (HSDS) and body mass index (BMI) SDS from baseline through year 4. Analyses were repeated with ADHD groups matched for baseline age, height, weight, BMI, and sex. Groups with and without GHD were compared between ADHD groups.

RESULTS

Adjusted change in HSDS for the group receiving ADHD stimulant medication was slightly lower than that for patients not receiving stimulant medication at years 1 to 4 (P < .05). However, adjusted change in HSDS was similar between children receiving and not receiving ADHD stimulant medication when matched for baseline measurements. At year 4, 86.7% of patients receiving ADHD stimulant medication, 86.8% of total patients not receiving ADHD stimulant medication, and 84.6% of matched group patients not receiving ADHD stimulant medication achieved HSDS >-2. Year 4 adjusted change in BMI SDS was greater in the patients receiving ADHD stimulant medication compared with both groups not receiving ADHD stimulant medication (P < .05). Patients with GHD showed comparable differences in adjusted change in BMI SDS among the ADHD groups at year 4, whereas patients without GHD showed no significant differences.

CONCLUSIONS

ADHD medication did not affect the linear growth response of children treated with GH when those receiving or not receiving ADHD stimulant medication were matched for baseline measurements. Underlying reasons for the observed greater increase in BMI in patients with GHD concomitantly treated with ADHD medication remain to be elucidated.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01009905.

Use of human growth hormone in a cachectic post-traumatic crush injury patient

Somatropin, recombinant human growth hormone, is used for the treatment of growth hormone deficiencies and conditions with associated weight loss. A 42-year-old male was admitted to the trauma service after suffering a traumatic crush injury. Approximately five months later, the patient was readmitted due to cachexia and intractable vomiting. Somatropin (0.1 mg/kg) injection therapy was initiated. This was a novel therapeutic approach to a patient that was otherwise declining. Despite complications with nutrition, somatropin appeared to augment weight gain.

A Comparison of transgenic and wild type soybean seeds: analysis of transcriptome profiles using RNA-Seq

BACKGROUND

Soybean (Glycine max) has been bred for thousands of years to produce seeds rich in protein for human and animal consumption, making them an appealing bioreactor for producing valuable recombinant proteins at high levels. However, the effects of expressing recombinant protein at high levels on bean physiology are not well understood. To address this, we investigated whether gene expression within transgenic soybean seed tissue is altered when large amounts of recombinant proteins are being produced and stored exclusively in the seeds. We used RNA-Seq to survey gene expression in three transgenic soybean lines expressing recombinant protein at levels representing up to 1.61 % of total protein in seed tissues. The three lines included: ST77, expressing human thyroglobulin protein (hTG), ST111, expressing human myelin basic protein (hMBP), and 764, expressing a mutant, nontoxic form of a staphylococcal subunit vaccine protein (mSEB). All lines selected for analysis were homozygous and contained a single copy of the transgene.

METHODS

Each transgenic soybean seed was screened for transgene presence and recombinant protein expression via PCR and western blotting.  Whole seed mRNA was extracted and cDNA libraries constructed for Illumina sequencing.  Following alignment to the soybean reference genome, differential gene expression analysis was conducted using edgeR and cufflinks.  Functional analysis of differentially expressed genes was carried out using the gene ontology analysis tool AgriGO.

RESULTS

The transcriptomes of nine seeds from each transgenic line were sequenced and compared with wild type seeds. Native soybean gene expression was significantly altered in line 764 (mSEB) with more than 3000 genes being upregulated or downregulated. ST77 (hTG) and ST111 (hMBP) had significantly less differences with 52 and 307 differentially expressed genes respectively. Gene ontology enrichment analysis found that the upregulated genes in the 764 line were annotated with functions related to endopeptidase inhibitors and protein synthesis, but suppressed expression of genes annotated to the nuclear pore and to protein transport. No significant gene ontology terms were detected in ST77, and only a few genes involved in photosynthesis and thylakoid functions were downregulated in ST111. Despite these differences, transgenic plants and seeds appeared phenotypically similar to non-transgenic controls. There was no correlation between recombinant protein expression level and the quantity of differentially expressed genes detected.

CONCLUSIONS

Measurable unscripted gene expression changes were detected in the seed transcriptomes of all three transgenic soybean lines analyzed, with line 764 being substantially altered. Differences detected at the transcript level may be due to T-DNA insert locations, random mutations following transformation or direct effects of the recombinant protein itself, or a combination of these. The physiological consequences of such changes remain unknown.

Prokaryotic soluble overexpression and purification of bioactive human growth hormone by fusion to thioredoxin, maltose binding protein, and protein disulfide isomerase

Human growth hormone (hGH) is synthesized by somatotroph cells of the anterior pituitary gland and induces cell proliferation and growth. This protein has been approved for the treatment of various conditions, including hGH deficiency, chronic renal failure, and Turner syndrome. Efficient production of hGH in Escherichia coli (E. coli) has proven difficult because the E. coli-expressed hormone tends to aggregate and form inclusion bodies, resulting in poor solubility. In this study, seven N-terminal fusion partners, hexahistidine (His6), thioredoxin (Trx), glutathione S-transferase (GST), maltose-binding protein (MBP), N-utilization substance protein A (NusA), protein disulfide bond isomerase (PDI), and the b′a′ domain of PDI (PDIb′a′), were tested for soluble overexpression of codon-optimized hGH in E. coli. We found that MBP and hPDI tags significantly increased the solubility of the hormone. In addition, lowering the expression temperature to 18°C also dramatically increased the solubility of all the fusion proteins. We purified hGH from MBP-, PDIb′a′-, or Trx-tagged hGH expressed at 18°C in E. coli using simple chromatographic techniques and compared the final purity, yield, and activity of hGH to assess the impact of each partner protein. Purified hGH was highly pure on silver-stained gel and contained very low levels of endotoxin. On average, ∼37 mg, ∼12 mg, and ∼7 mg of hGH were obtained from 500 mL-cell cultures of Trx-hGH, MBP-hGH, and PDIb′a′-hGH, respectively. Subsequently, hGH was analyzed using mass spectroscopy to confirm the presence of two intra-molecular disulfide bonds. The bioactivity of purified hGHs was demonstrated using Nb2-11 cell.

Slipped capital femoral epiphysis in a patient with Turner syndrome receiving growth hormone therapy

OBJECTIVE

To report a case of slipped capital femoral epiphysis in a young patient with Turner syndrome (TS) receiving growth hormone therapy and to emphasize the importance of keeping this orthopedic condition in mind during management of this patient group.

METHODS

Clinical, laboratory, and radiographic findings are presented, and risk factors for slipped capital femoral epiphysis are discussed.

RESULTS

A child with TS presented for medical assessment because of a limp but with no history of trauma or febrile illness. Growth hormone therapy had been administered for 1 year because of her short stature. Physical examination and pelvic radiography of the patient showed the presence of bilateral slipped capital femoral epiphysis. She underwent bilateral pinning in situ, and growth hormone therapy was terminated. At follow-up after more than 2 years, no sequelae were noted.

CONCLUSION

Patients with TS are at high risk for developing certain orthopedic conditions, such as slipped capital femoral epiphysis. Furthermore, slipped capital femoral epiphysis is a known complication of growth hormone therapy in growing children. A limp, hip pain, knee pain, or thigh pain might be a symptom of slipped capital femoral epiphysis in patients with TS, especially those receiving growth hormone therapy. Prompt recognition and treatment of this condition are important for prevention of sequelae.

PASylation: a biological alternative to PEGylation for extending the plasma half-life of pharmaceutically active proteins

A major limitation of biopharmaceutical proteins is their fast clearance from circulation via kidney filtration, which strongly hampers efficacy both in animal studies and in human therapy. We have developed conformationally disordered polypeptide chains with expanded hydrodynamic volume comprising the small residues Pro, Ala and Ser (PAS). PAS sequences are hydrophilic, uncharged biological polymers with biophysical properties very similar to poly-ethylene glycol (PEG), whose chemical conjugation to drugs is an established method for plasma half-life extension. In contrast, PAS polypeptides offer fusion to a therapeutic protein on the genetic level, permitting Escherichia coli production of fully active proteins and obviating in vitro coupling or modification steps. Furthermore, they are biodegradable, thus avoiding organ accumulation, while showing stability in serum and lacking toxicity or immunogenicity in mice. We demonstrate that PASylation bestows typical biologics, such as interferon, growth hormone or Fab fragments, with considerably prolonged circulation and boosts bioactivity in vivo.

Limb lengthening in children with Russell-Silver syndrome: a comparison to other etiologies

INTRODUCTION/BACKGROUND

Russell-Silver syndrome (RSS) is the combination of intrauterine growth retardation, difficulty feeding, and postnatal growth retardation. Leg length discrepancy (LLD) is one of four major diagnostic criteria of RSS and is present in most cases. We aimed to ascertain whether pediatric RSS patients will adequately consolidate bony regenerate following leg lengthening.

MATERIALS AND METHODS

We retrospectively reviewed pediatric RSS patients who underwent limb lengthening and compared them to a similar group of patients with LLD resulting from tumor, trauma, or congenital etiology. The primary outcome measurement was the bone healing index (BHI).

RESULTS

The RSS group included seven lengthened segments in five patients; the comparison group included 21 segments in 19 patients. The groups had similar lengthening amounts (3.3 vs. 3.9 cm, p = 0.507). The RSS group healed significantly faster (lower BHI) than the control group (BHI 29 vs. 43 days/cm, p = 0.028). Secondary analysis showed no difference between RSS and trauma patients in terms of the BHI (29 vs. 31); however, the BHI of the RSS group was significantly lower than both of the other congenital etiologies (29 vs. 41, p = 0.032) and tumor patients (29 vs. 66, p = 0.019). The RSS patients had fewer and less significant complications than the controls.

DISCUSSION

The limb lengthening regenerate healing of RSS patients is faster than the healing of patients with other congenital etiologies and tumor patients, and is as fast as the regenerate healing of patients with posttraumatic LLD. Although all RSS patients were treated with human growth hormone (hGH), we are unable to isolate the hGH contribution to the regenerate bone healing. We conclude that RSS patients can have safe limb lengthening.

Growth and growth disorders in children and adolescents

Evaluation of a child's growth is one of the most important aspects of the general pediatric visit. Concerns about abnormal growth are the leading reasons general pediatricians refer patients to a pediatric endocrinologist. There is wide variation in normal growth patterns and an even greater variety of conditions that manifest with growth abnormalities. Here, we review patterns of normal growth in the pediatric and adolescent populations. We then review abnormal patterns of growth that require further evaluation and possible treatment.

A multi-center controlled trial of growth hormone treatment in children with cystic fibrosis

OBJECTIVES

We evaluated safety and efficacy of recombinant human growth hormone (rhGH) for improving growth, lean body mass (LBM), pulmonary function, and exercise tolerance in children with cystic fibrosis (CF) and growth restriction.

STUDY DESIGN

Multicenter, open-label, controlled clinical trial comparing outcomes in prepubertal children <14 years with CF, randomized in a 1:1 ratio to receive daily rhGH (Nutropin AQ) or no treatment (control) for 12 months, followed by a 6-month observation (month 18). Safety was monitored at each visit, including assessments of glucose tolerance.

RESULTS

Sixty-eight subjects were randomized (control n = 32; rhGH n = 36). Mean height standard deviation score (SDS) in the rhGH group increased by 0.5 ± 0.4 at 12 months (mean ± SD, P < 0.001); the control group height SDS remained unchanged. Weight increased by 3.8 ± 1.8 versus 2.8 ± 1.5 kg, (mean ± SD, P = 0.0356) and LBM increased by 3.8 ± 1.8 versus 2.1 ± 1.4 kg (P = 0.0002) in the rhGH group versus controls, respectively. Forced vital capacity increased by 325 ± 319 in the rhGH group compared with 178 ± 152 ml in controls (mean ± SD, P = 0.032). Forced expiratory volume in 1 sec improved in both groups with a significant difference between groups after adjustment for baseline severity (LS mean ± SE: rhGH, 224 ± 37, vs. controls, 108 ± 40 ml; P = 0.04). There was no difference between groups in exercise tolerance (6-min walk distance) at 1 year. Changes in glucose tolerance for the two groups were similar over the 12-month study period, with three subjects developing IGT and one CFRD in each group. One rhGH-treated patient developed increased intracranial pressure.

CONCLUSIONS

Treatment with rhGH in prepubertal children with CF was effective in promoting growth, weight, LBM, lung volume, and lung flows, and had an acceptable safety profile.

Aromatase inhibitors to augment height: continued caution and study required

Aromatase inhibitors (AIs) are a class of drugs that prevent conversion of androgens to estrogens, and that are approved in the United States as adjunctive treatment of estrogen receptor-positive breast cancer. Because ultimate fusion of the growth plates is estrogen-dependent in both boys and girls, AI administration may help to slow down epiphysial maturation and allow for greater height potential. Research trials in children with short stature have predominantly been done in Finland and Florida. Despite the apparent efficacy described by these groups, only ~110 children worldwide have been treated with AIs in research protocols (and usually concomitant with other growth-promoting agents) as of the end of 2008 (and none to final height). That said, many children are being treated with AI's in the United States outside of research protocols. Furthermore, little is known about the short- and long-term safety of AIs in children. Thus, it is imperative that there be well-designed, long-term studies of efficacy and safety of AI use in pediatric populations.

History of growth hormone therapy

Although the importance of the pituitary gland for growth was recognized in late 19(th) century, Growth hormone (GH) therapy was made available for severely GH-deficient children and adolescents only in late 1950s. Use of GH for other conditions was limited because of the limited supply of human pituitary-derived hormone. With unlimited availability of recombinant human GH (rhGH), the scenario of GH treatment has been changed enormously. Currently there is ever increasing list of indications of GH treatment in children, adolescents, and adults.

Emerging options in growth hormone therapy: an update

Growth hormone (GH) was first used to treat a patient in 1958. For the next 25 years it was available only from cadaver sources, which was of concern because of safety considerations and short supply. In 1985, GH produced by recombinant DNA techniques became available, expanding its possible uses. Since that time there have been three indications approved by the US Food and Drug Administration (FDA) for GH-deficiency states and nine indications approved for non-GH-deficiency states. In 2003 the FDA approved GH for use in idiopathic short stature (ISS), which may indirectly cover other diagnoses that have short stature as a feature. However, coverage for GH therapy is usually more reliably obtainable for a specific indication, rather than the ISS indication. Possible future uses for GH therapy could include the treatment of syndromes such as Russell-Silver syndrome or chondrodystrophy. Other non-short-stature indications could include wound healing and burns. Other uses that have been poorly studied include aging and physical performance, in spite of the interest already shown by elite athletes in using GH. The safety profile of GH developed over the past 25 years has shown it to be a very safe hormone with few adverse events associated with it. The challenge for the future is to follow these patients into adulthood to determine whether GH therapy poses any long-term risks.

Orthopedic complications related to growth hormone therapy in a pediatric population

Since the introduction of recombinant growth hormone, its use has diversified and multiplied. Growth hormone is now the recommended therapy for a growing indication to all forms of short stature because of its direct and indirect role on bone growth. Hereby, we discuss the orthopedic complications associated with growth hormone treatment in pediatric patients. These complications include carpal tunnel syndrome, Legg-Calve-Perthes' disease, scoliosis, and slipped capital femoral epiphysis. Their incidence rates recorded in several growth hormone therapy-related pharmacovigilance studies will be summarized in this study with focused discussion on their occurrence in the pediatric and adolescent age groups. The pathogenesis of these complications is also reviewed.

Managing idiopathic short stature: role of somatropin (rDNA origin) for injection

Idiopathic short stature (ISS) is a term that describes short stature in children who do not have growth hormone (GH) deficiency and in whom the etiology of the short stature is not identified. Between 1985 and 2000, more than 40 studies were published regarding GH therapy for ISS. Only 12 of these had data to adult height, of which only 4 were controlled studies. A subsequent placebo-controlled study that followed subjects to adult height indicated that there was a gain of 3.7–7.5 cm in height with GH treatment. In 2003, the US Federal Drug Administration (FDA) approved GH for treatment of short stature. Even before FDA approval, patients with ISS made up about 20% of patients in GH databases, which is largely unchanged since FDA approval. There remains some controversy as to whether GH should be used to treat ISS. This controversy centers on the fact that there has been no definitive demonstration that short stature results in a disadvantage or problems with psychological adjustment, and thus, no demonstration that GH therapy results in improvement in quality of life.

Somatotropin in the treatment of growth hormone deficiency and Turner syndrome in pediatric patients: a review

Growth hormone (GH), also known as somatotropin, is a peptide hormone that is synthesized and secreted by the somatotrophs of the anterior pituitary gland. The main action of GH is to stimulate linear growth in children; however, it also fosters a healthy body composition by increasing muscle and reducing fat mass, maintains normal blood glucose levels, and promotes a favorable lipid profile. This article provides an overview of the normal pathophysiology of GH production and action. We discuss the history of GH therapy and the development of the current formulation of recombinant human GH given as daily subcutaneous injections. This paper reviews two of the longest standing FDA-approved indications for GH treatment, GH deficiency and Turner syndrome. We will highlight the pathogenesis of these disorders, including presentations, presumed mechanism(s) for the associated short stature, and diagnostic criteria, with a review of stimulation test benefits and pitfalls. This review also includes current recommendations for GH therapy to help maximize final height in these children, as well as data demonstrating the efficacy and safety of GH treatment in these populations.