The effects of growth hormone replacement therapy on bone metabolism in adult-onset growth hormone deficiency: a 2-year open randomized controlled multicenter trial

Hypopituitarism and bone disease: pathophysiology, diagnosis and treatment outcomes

Hypopituitarism is a rare but significant endocrine disorder characterized by the inadequate secretion of one or more pituitary hormones. The intricate relationship between hypopituitarism and bone health is a topic of growing interest in the medical community. In this review the authors explore associations between hypopituitarism and bone health, with specific examination of the impact of growth hormone deficiency, central hypogonadism, central hypocortisolism, and central hypothyroidism. Pathogenesis, diagnosis, and treatment options as well as challenges posed by osteopenia, osteoporosis, and fractures in hypopituitarism are discussed.

Differences between bone health parameters in adults with acromegaly and growth hormone deficiency: A systematic review

Preserving bone health is an important goal of care of patients with acromegaly and growth hormone deficiency (GHD). Both disorders are associated with compromised bone health and an increased risk of fracture. However, parameters of bone health that are routinely used to predict fractures in other populations, such as aBMD measured by DXA, are unreliable for this in acromegaly and GHD. Additional methodologies need to be employed to assess bone health in these patients. This review summarizes available data on the effects of acromegaly and GHD on parameters of bone health such as aBMD, volumetric bone mineral density (vBMD) and microarchitecture assessed by HRpQCT and other techniques, trabecular bone score (TBS) and fracture assessment. More research is needed to identify reliable predictors of fracture risk and to determine how best to screen for and treat those patients at risk so that bone health is optimized in these patients.

Skeletal disorders associated with the growth hormone-insulin-like growth factor 1 axis

Growth hormone (GH) and insulin-like growth factor 1 (IGF1) are important regulators of bone remodelling and metabolism and have an essential role in the achievement and maintenance of bone mass throughout life. Evidence from animal models and human diseases shows that both GH deficiency (GHD) and excess are associated with changes in bone remodelling and cause profound alterations in bone microstructure. The consequence is an increased risk of fractures in individuals with GHD or acromegaly, a condition of GH excess. In addition, functional perturbations of the GH-IGF1 axis, encountered in individuals with anorexia nervosa and during ageing, result in skeletal fragility and osteoporosis. The effect of interventions used to treat GHD and acromegaly on the skeleton is variable and dependent on the duration of the disease, the pre-existing skeletal state, coexistent hormone alterations (such as those occurring in hypogonadism) and length of therapy. This variability could also reflect the irreversibility of the skeletal structural defect occurring during alterations of the GH-IGF1 axis. Moreover, the effects of the treatment of GHD and acromegaly on locally produced IGF1 and IGF binding proteins are uncertain and in need of further study. This Review highlights the pathophysiological, clinical and therapeutic aspects of skeletal fragility associated with perturbations in the GH-IGF1 axis.

Update on vertebral fractures in pituitary diseases: from research to clinical practice

Derangement of pituitary hormone axes can induce changes in bone remodeling and metabolism with possible alterations in bone microarchitectural structure and increased susceptibility to fractures. Vertebral fractures (VFs), which are a hallmark of skeletal fragility, have been described in a very large number of patients with pituitary diseases. These fractures are clinically relevant, since they predispose to further fractures and may negatively impact on patients' quality of life. However, the management of skeletal fragility and VFs in the specific setting of pituitary diseases is a challenge, since the awareness for this disease is still low, prediction of VFs is uncertain, the diagnosis of VFs cannot be solely based on a clinical approach and also needs a radiological and morphometric approach, the risk of fractures may not be decreased via treatment of pituitary hormone disorders, and the effectiveness of bone-active drugs in this setting is not always evidence-based. This review is an update on skeletal fragility in patients with pituitary diseases, with a focus on clinical and therapeutic aspects concerning the management of VFs.

Safety and effectiveness of replacement with biosimilar growth hormone in adults with growth hormone deficiency: results from an international, post-marketing surveillance study (PATRO Adults)

PURPOSE

To evaluate safety and effectiveness of biosimilar recombinant human growth hormone (rhGH; Omnitrope®) in adults with growth hormone deficiency (GHD), using data from the PATRO Adults study.

METHODS

PATRO Adults was a post-marketing surveillance study conducted in hospitals and specialized endocrinology units across Europe. The primary objective was to assess the safety of rhGH in adults treated in routine clinical practice. All adverse events (AEs) were monitored and recorded for the complete duration of Omnitrope® treatment. Effectiveness was evaluated as a secondary objective.

RESULTS

As of January 2020, 1447 patients (50.9% male) had been enrolled from 82 centers in 9 European countries. Most patients had adult-onset GHD (n = 1179; 81.5%); 721 (49.8%) were rhGH-naïve at study entry. Overall, 1056 patients (73.0%) reported adverse events (AEs; n = 5397 events); the majority were mild-to-moderate in intensity. Treatment-related AEs were reported in 117 patients (8.1%; n = 189 events); the most commonly reported (MedDRA preferred terms) were arthralgia (n = 19), myalgia (n = 16), headache (n = 14), and edema peripheral (n = 10). In total, 495 patients (34.2%) had serious AEs (SAEs; n = 1131 events); these were considered treatment-related in 28 patients (1.9%; n = 35 events). Mean (standard deviation) IGF-I SDS increased from - 2.34 (1.47) at baseline to - 0.23 (1.65) at 12 months, and remained relatively stable thereafter (up to 3 years). Body mass index remained stable between baseline and 3 years.

CONCLUSION

Data from PATRO Adults indicate biosimilar rhGH (Omnitrope^®) is not associated with any unexpected safety signals, and is effective in adults with GHD treated in real-world clinical practice.

3D DXA Hip Differences in Patients with Acromegaly or Adult Growth Hormone Deficiency

The skeleton is regulated by and responds to pituitary hormones, especially when the circulating levels are perturbed in disease. This study aims to analyse the between-group differences in 3D dual-energy X-ray absorptiometry (DXA) parameters at the hip site among patients with acromegaly or adult growth hormone deficiency (AGHD) and a healthy control group. The current cross-sectional study includes data for 67 adults, 20 with acromegaly, 14 with AGHD and 33 healthy controls. We obtained the areal bone mineral density (aBMD) outcomes using DXA and cortical and trabecular parameters using 3D-DXA software (3D-SHAPER). The mean-adjusted 3D-DXA parameters did not differ between acromegaly patients and the controls (p > 0.05); however, we found cortical bone impairment (−7.3% to −8.4%; effect size (ES) = 0.78) in AGHD patients (p < 0.05). Differences in the cortical bone parameters were more evident when comparing AGHD patients (−8.5% to −16.2%; ES = 1.22 to 1.24) with acromegaly patients (p < 0.05). In brief, the 3D mapping highlighted the trochanter as the site with greater cortical bone differences between acromegaly patients and the controls. Overall, AGHD patients displayed lower cortical parameters at the trochanter, femoral neck and intertrochanter compared to the controls and acromegaly patients. To sum up, 3D-DXA provided useful information about the characteristics of bone involvement in growth hormone (GH)-related disorders. Patients with AGHD showed distinct involvement of the cortical structure.

Biochemical bone turnover markers in hormonal disorders in adults: a narrative review

BACKGROUND

Hormonal disorders are often associated with abnormal levels of bone turnover markers (BTMs). N-terminal propeptide of type I procollagen (PINP) and serum C-terminal cross-linking telopeptide of type I collagen (CTX-I) are the reference markers of bone formation and bone resorption, respectively.

METHODS

A comprehensive literature search within the MEDLINE and Web of Science databases was performed.

RESULTS

Acromegaly is associated with higher BTM levels, which decrease during the remission after treatment. Adult-onset growth hormone deficiency is often associated with decreased BTM levels. Growth hormone replacement therapy stimulates bone turnover and increases BTM levels. Hypothyroidism is characterized by general slowing of bone metabolism which is reflected by lower BTM levels. The replacement thyroid hormone therapy increases the bone turnover rate and BTM levels increase. Patients with thyroid cancer receive a suppressive dose of thyroid hormones and may have slightly elevated BTM levels. Patients with overt hyperthyroidism had higher BTM levels and anti-thyroid therapy induces a rapid decrease in the BTM levels. Patients with overt primary hyperparathyroidism have higher BTM levels, whereas those with asymptomatic and normocalcemic hyperparathyroidism usually have normal BTM levels. Hypoparathyroidism is characterized by slightly decreased BTM levels. Cushing's syndrome is characterized consistently by markedly decreased osteocalcin concentration, whereas data on other BTMs are discordant.

CONCLUSIONS

BTMs help us to better understand mechanisms of the impact of hormonal disorders and their treatment on bone metabolism. However, it is unknown whether BTMs may be used to monitor the effect of their treatments on bone in the clinical practice.

Effects of 24 Weeks of Growth Hormone Treatment on Bone Microstructure and Volumetric Bone Density in Patients with Childhood-Onset Adult GH Deficiency

OBJECTIVE

Adults with childhood-onset growth hormone deficiency (CO AGHD) have prominently impaired volumetric bone density (vBMD) and bone microarchitecture. Effects of recombinant human growth hormone (rhGH) on bone microarchitecture in CO AGHD were insufficiently evaluated. The objective of this study is to assess the effects of rhGH on bone microarchitecture and vBMD in CO AGHD patients.

DESIGN

In this single-center prospective study, nine CO AGHD patients received rhGH treatment for 24 weeks. High-resolution peripheral quantitative computerized tomography (HR-pQCT) of distal tibia and radius was performed at baseline and at the end of treatment. Main outcomes were vBMD and morphometric parameters from HR-pQCT.

RESULTS

After 24-week treatment, IGF-1 SDS gradually increased from -3.31 ± 1.56 to -1.92 ± 1.65 (p=0.113). Serum phosphate (1.17 ± 0.17 vs. 1.35 ± 0.18 mmol/L, p=0.030), alkaline phosphatase (83.6 ± 38.6 vs. 120.5 ± 63.7, p=0.045), and β-CTX (0.67 ± 0.32 vs. 1.09 ± 0.58, p=0.022) were significantly elevated. In distal tibia, total vBMD (200.2 ± 41.7 vs 210.3 ± 40.9 mg HA/cm³, p=0.017), cortical area (89.9 ± 17.7 vs 95.5 ± 19.9 mm², p=0.032), and cortical thickness (0.891 ± 0.197 vs 0.944 ± 0.239 mm, p=0.028) were significantly improved. Trabecular area decreased from 795.3 ± 280.9 to 789.6 ± 211.4 mm² (p=0.029). Trabecular bone volume fraction increased from 0.193 ± 0.038 to 0.198 ± 0.036 (p=0.027). In radius, cortical perimeter (74.1 ± 10.0 vs 75.0 ± 10.9 mm, p=0.034), trabecular thickness (0.208 ± 0.013 vs 0.212 ± 0.013 mm, p=0.008), trabecular separation (0.743 ± 0.175 vs 0.796 ± 0.199 mm, p=0.019), and inhomogeneity of network (Tb.1/N.SD) (0.292 ± 0.087 vs 0.317 ± 0.096 mm, p=0.026) were significantly improved, while trabecular number (1.363 ± 0.294 vs 1.291 ± 0.325 1/mm, p=0.025) decreased significantly.

CONCLUSIONS

Our results provide evidence for improvement of vBMD and bone microarchitecture in AGHD patients at a relatively early stage of rhGH treatment.

[Current aspects of diagnosis and treatment of adult GH-deficiency]

Adult growth hormone (GH) deficiency (AGHD) is a condition characterized by alterations in body composition, lipid and carbohydrate metabolism, bone mineral density and poor quality of life; however, clinical presentations of AGHD are mostly non-specific. Untreated AGHD is associated with increased cardiovascular morbidity and mortality. Stimulation tests are used for the diagnosis: insulin tolerance test, glucagon stimulation test, growth-hormone releasing hormone and arginine stimulation test. Moreover, in 2017 FDA approved the use of macimorelin (oral GH secretagogue) for the diagnosis of AGHD. In childhood GH-deficiency, apolipoprotein A-IV, CFHR4 (complement factor H-related protein 4) and PBP (platelet basic protein) were identified as potential biomarkers of the disease, however, this was not investigated in AGHD. GH treatment starts from the minimal dose, which allows minimizing the adverse effects. According to published meta-analyses, AGHD treatment generally does not lead to increased risk of malignancy and recurrence of sellar neoplasms in adult patients. Published data on GH receptor polymorphism associations with treatment efficacy remains controversial. Development of long-acting GH formulations is a currect perspective for the increase of treatment compliance.

Pituitary Diseases and Bone

Neuroendocrinology of bone is a new area of research based on the evidence that pituitary hormones may directly modulate bone remodeling and metabolism. Skeletal fragility associated with high risk of fractures is a common complication of several pituitary diseases such as hypopituitarism, Cushing disease, acromegaly, and hyperprolactinemia. As in other forms of secondary osteoporosis, pituitary diseases generally affect bone quality more than bone quantity, and fractures may occur even in the presence of normal or low-normal bone mineral density as measured by dual-energy X-ray absorptiometry, making difficult the prediction of fractures in these clinical settings. Treatment of pituitary hormone excess and deficiency generally improves skeletal health, although some patients remain at high risk of fractures, and treatment with bone-active drugs may become mandatory. The aim of this review is to discuss the physiological, pathophysiological, and clinical insights of bone involvement in pituitary diseases.

The effect of growth hormone replacement in patients with hypopituitarism on pituitary tumor recurrence, secondary cancer, and stroke

Growth hormone replacement therapy has benefits for patients with hypopituitarism. The safety profile in regard to tumor recurrence or progression, development of secondary malignancies, or cerebrovascular stroke is still an area of debate. A comprehensive search of multiple databases-MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus was conducted through August 2015. Eligible studies that evaluated long-term adverse events in adult patients with hypopituitarism treated with growth hormone replacement therapy and reported development of pituitary tumor recurrence or progression, secondary malignancies, or cerebrovascular stroke were selected following a predefined protocol. Reviewers, independently and in duplicate, extracted data and assessed the risk of bias. Random-effects meta-analysis was used to pool relative risks and 95 % confidence intervals. We included 15 studies (published 1995-2015) that reported on 46,148 patients. Compared to non-replacement, growth hormone replacement therapy in adults with hypopituitarism was not associated with statistically significant change in pituitary tumor progression or recurrence (relative risk, 0.77; 95 % confidence interval, 0.53-1.13) or development of secondary malignancy (relative risk, 0.99; 95 % confidence interval, 0.70-1.39). In two retrospective studies, there was higher risk of stroke in patients who did not receive replacement (relative risk, 2.07; 95 % confidence interval, 1.51-2.83). The quality of evidence is low due to study limitations and imprecision. This systematic review and meta-analysis supports the overall safety of growth hormone therapeutic use in adults with hypopituitarism with no clear evidence of increased risk of pituitary tumor recurrence, malignancy, or stroke.

Management of GH treatment in adult GH deficiency

Growth hormone (GH) replacement therapy in adults with GH deficiency is still a challenge for the clinical endocrinologist and its implementation has still numerous difficulties and uncertainties. The decision to treat GH deficient adults requires a thoughtful and individualized evaluation of risks and benefits. Benefits have been found in body composition, bone health, cardiovascular risk factors, and quality of life. However, evidences for a reduction in cardiovascular events and mortality are still lacking, and treatment costs remain high. It is advisable to start treatment with low doses of GH, the goals being an appropriate clinical response, an avoidance of side effects, and IGF-I levels in the age-adjusted reference range. Although treatment appears to be overall safe, certain areas continue to require long-term surveillance, such as risks of glucose intolerance, pituitary/hypothalamic tumor recurrence, and cancer.

Combined Effects of Androgen and Growth Hormone on Osteoblast Marker Expression in Mouse C2C12 and MC3T3-E1 Cells Induced by Bone Morphogenetic Protein

Osteoblasts undergo differentiation in response to various factors, including growth factors and steroids. Bone mass is diminished in androgen- and/or growth hormone (GH)-deficient patients. However the functional relationship between androgen and GH, and their combined effects on bone metabolism, remains unclear. Here we investigated the mutual effects of androgen and GH on osteoblastic marker expression using mouse myoblastic C2C12 and osteoblast-like MC3T3-E1 cells. Combined treatment with dihydrotestosterone (DHT) and GH enhanced BMP-2-induced expression of Runx2, ALP, and osteocalcin mRNA, compared with the individual treatments in C2C12 cells. Co-treatment with DHT and GH activated Smad1/5/8 phosphorylation, Id-1 transcription, and ALP activity induced by BMP-2 in C2C12 cells but not in MC3T3-E1 cells. The insulin-like growth factor (IGF-I) mRNA level was amplified by GH and BMP-2 treatment and was restored by co-treatment with DHT in C2C12 cells. The mRNA level of the IGF-I receptor was not significantly altered by GH or DHT, while it was increased by IGF-I. In addition, IGF-I treatment increased collagen-1 mRNA expression, whereas blockage of endogenous IGF-I activity using an anti-IGF-I antibody failed to suppress the effect of GH and DHT on BMP-2-induced Runx2 expression in C2C12 cells, suggesting that endogenous IGF-I was not substantially involved in the underlying GH actions. On the other hand, androgen receptor and GH receptor mRNA expression was suppressed by BMP-2 in both cell lines, implying the existence of a feedback action. Collectively the results showed that the combined effects of androgen and GH facilitated BMP-2-induced osteoblast differentiation at an early stage by upregulating BMP receptor signaling.

Seven years of follow up of trabecular bone score, bone mineral density, body composition and quality of life in adults with growth hormone deficiency treated with rhGH replacement in a single center

BACKGROUND

Adult growth hormone deficiency (AGHD) is characterized by impaired physical activity, diminished quality of life (QoL), weight and fat mass gain, decreased muscle mass and decreased bone mineral density (BMD). The aim of this study was to evaluate the effects of long-term treatment (7 years) with recombinant human growth hormone (rhGH) on metabolic parameters, body composition (BC), BMD, bone microarchitecture and QoL.

PATIENTS AND METHODS

In this prospective study, BMD and BC were assessed by dual-energy X-ray absorptiometry (DXA). Bone microarchitecture was assessed with the trabecular bone score (TBS). The QoL-AGHDA test was used to assess QoL.

RESULTS

A total of 18 AGHD patients (mean age, 37.39 ± 12.42) were included. Body weight and body mass index (BMI) showed a significant increase after 7 years (p = 0.03 and p = 0.001, respectively). There was a significant tendency of body fat mass (BFM) (p = 0.028) and lean body mass (LBM) (p = 0.005) to increase during the 7 years of rhGH treatment. There was a significant increase in lumbar spine (LS) BMD (p = 0.01). TBS showed a nonsignificant decrease after 7 years of treatment, with a change of -0.86% ± 1.95. QoL showed a large and significant improvement (p = 0.02).

CONCLUSION

Long-term rhGH treatment in AGHD patients induces a large and sustained improvement in QoL. Metabolic effects are variable with an increase in LBM as well as in BMI and BFM. There is a positive effect on BMD based on the increase in LS BMD, which stabilizes during long-term therapy and is not associated with a similar increase in bone microarchitecture.

Does the GH/IGF-1 axis contribute to skeletal sexual dimorphism? Evidence from mouse studies

The contribution of the gonadotropic axis to skeletal sexual dimorphism (SSD) was clarified in recent years. Studies with animal models of estrogen receptor (ER) or androgen receptor (AR) null mice, as well as mice with bone cell-specific ablation of ER or AR, revealed that both hormones play major roles in skeletal acquisition, and that estrogen regulates skeletal accrual in both sexes. The growth hormone (GH) and its downstream effector, the insulin-like growth factor-1 (IGF-1) are also major determinants of peak bone mass during puberty and young adulthood, and play important roles in maintaining bone integrity during aging. A few studies in both humans and animal models suggest that in addition to the differences in sex steroid actions on bone, sex-specific effects of GH and IGF-1 play essential roles in SSD. However, the contributions of the somatotropic (GH/IGF-1) axis to SSD are controversial and data is difficult to interpret. GH/IGF-1 are pleotropic hormones that act in an endocrine and autocrine/paracrine fashion on multiple tissues, affecting body composition as well as metabolism. Thus, understanding the contribution of the somatotropic axis to SSD requires the use of mouse models that will differentiate between these two modes of action. Elucidation of the relative contribution of GH/IGF-1 axis to SSD is significant because GH is approved for the treatment of normal children with short stature and children with congenital growth disorders. Thus, if the GH/IGF-1 axis determines SSD, treatment with GH may be tailored according to sex. In the following review, we give an overview of the roles of sex steroids in determining SSD and how they may interact with the GH/IGF-1 axis in bone. We summarize several mouse models with impaired somatotropic axis and speculate on the possible contribution of that axis to SSD.

Reviewing the safety of GH replacement therapy in adults

CONTEXT

Systematic data on safety of growth hormone (GH) replacement therapy in adult GH deficiency is lacking.

OBJECTIVE

To systematically describe safety of adult GH replacement therapy on glucose metabolism and long term safety.

DESIGN

A systematic web-based search of PubMed was performed guided by the Standard Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

OUTCOME

Randomised controlled trials of ≥3 months and open trials for ≥12 months with more than 50 adult patients (50 patient years, prospective and retrospective) including adverse event reporting as well as articles on mortality primarily on adult onset patients, reporting mortality ratios on GH treated patients, were included for the review.

RESULTS

Based on the defined selection criteria 94 studies were included. The short-term early placebo controlled trials did not demonstrate an increased frequency of diabetes mellitus (DM) and the long-term open studies did not consistently show an increased incidence of DM during GH replacement. The concern that long-term GH replacement might increase the risk of primary cancer, secondary neoplasia after tumour treatment and recurrence of previous tumours was not evident in the study data.

CONCLUSION

Based on available data, short- and long-term adult GH replacement in patients with severe GH deficiency and hypopituitarism is safe. However, the small number of subjects, limitation of long-term of GH treatment data and absence of an adequate control population is still a limitation for the interpretation of these data.

Effects of up to 15 years of recombinant human GH (rhGH) replacement on bone metabolism in adults with growth hormone deficiency (GHD): the Leiden Cohort Study

BACKGROUND

Growth hormone deficiency (GHD) in adulthood may be associated with a decreased bone mineral density (BMD), a decreased bone mineral content (BMC) and an increased fracture risk. Recombinant human GH (rhGH) replacement induces a progressive increase in BMD for up to 5-7 years of treatment. Data on longer follow-up are, however, scarce.

METHODS

Two hundred and thirty-adult GHD patients (mean age 47·1 years, 52·6% female), of whom 88% patients had adult-onset (AO) GHD, receiving rhGH replacement for ≥5 years were included in the study. Most patients had multiple pituitary hormone deficiencies. Bone turnover markers, BMC and BMD and T-scores at the lumbar spine and femoral neck were evaluated at baseline, and after 5, 10 and 15 years of rhGH replacement. In addition, clinical fracture incidence was assessed.

RESULTS

Mean lumbar spine BMD, lumbar spine BMC and T-scores gradually increased during the first 10 years of rhGH replacement and remained stable thereafter. Largest effects of rhGH supplementation were found in men. In the small subset of patients using bisphosphonates, use of bisphosphonates did not impact additional beneficial effects in the long term. Low baseline BMD positively affected the change in BMD and BMC over time, but there was a negative effect of high GH dose at 1 year on the change in BMD and BMC over time. Clinical fracture incidence during long-term rhGH replacement was 20.1/1000 py.

CONCLUSIONS

Fifteen years of rhGH replacement in GHD adults resulted in a sustained increase in BMD values at the lumbar spine, particularly in men, and stabilization of BMD values at the femoral neck. Clinical fracture incidence was suggested not to be increased during long-term rhGH replacement.

A reversible albumin-binding growth hormone derivative is well tolerated and possesses a potential once-weekly treatment profile

CONTEXT

Human growth hormone (hGH) replacement therapy currently requires daily sc injections for years/lifetime, which may be both inconvenient and distressing for patients. NNC0195-0092 is a novel hGH derivative intended for once-weekly treatment of GH deficiency. A noncovalent albumin binding moiety is attached to the hGH backbone. Clearance is reduced as a consequence of a reversible binding to circulating serum albumin, which prolongs the pharmacodynamic (PD) effect.

OBJECTIVE

To evaluate safety, local tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of a single dose (SD) and multiple doses (MD) of NNC0195-0092.

SETTING AND DESIGN

Randomized, single-center, placebo-controlled, double-blind, SD/MD, dose-escalation trial of 105 healthy male subjects. NNC0195-0092 sc administration: Five cohorts of eight subjects received one dose of NNC0195-0092 (0.01-0.32 mg/kg) (n = 6) or placebo (n = 2). Sixteen subjects (equal numbers of Japanese and non-Asian) received once-weekly doses of NNC0195-0092 (0.02-0.24 mg/kg; n=12) or placebo (n=4) for 4 weeks. Blood samples were drawn for assessment of safety, PK, IGF-1, and IGF binding protein 3 profiles and anti-drug antibodies.

RESULTS

SD and MD of NNC0195-0092 were well tolerated at all dose levels. No safety concerns or local tolerability issues were identified. A dose-dependent IGF-1 response was observed. IGF-1 profiles suggest that NNC0195-0092 may be suitable for once-weekly dosing, with a clinically relevant dose ≤0.08 mg/kg/week. No differences in PK and PD were observed between Japanese and non-Asian subjects.

CONCLUSIONS

SD and MD of NNC0195-0092 administered to healthy Japanese and non-Asian male subjects were well tolerated at all doses. The present trial suggests that NNC0195-0092 has the potential for an efficacious, well-tolerated, once-weekly GH treatment.

Effects of testosterone and growth hormone on the structural and mechanical properties of bone by micro-MRI in the distal tibia of men with hypopituitarism

CONTEXT

Severe deficiencies of testosterone (T) and GH are associated with low bone mineral density (BMD) and increased fracture risk. Replacement of T in hypogonadal men improves several bone parameters. Replacement of GH in GH-deficient men improves BMD.

OBJECTIVE

Our objective was to determine whether T and GH treatment together improves the structural and mechanical parameters of bone more than T alone in men with hypopituitarism.

DESIGN AND SUBJECTS

This randomized, prospective, 2-year study included 32 men with severe deficiencies of T and GH due to panhypopituitarism.

INTERVENTION

Subjects were randomized to receive T alone (n = 15) or T and GH (n = 17) for 2 years.

MAIN OUTCOME MEASURES

We evaluated magnetic resonance microimaging-derived structural (bone volume fraction [BVF] and trabecular thickness) and mechanical (axial stiffness [AS], a measure of bone strength) properties of the distal tibia at baseline and after 1 and 2 years of treatment.

RESULTS

Treatment with T and GH did not affect BVF, thickness, or AS differently from T alone. T treatment in all subjects for 2 years increased trabecular BVF by 9.6% (P < .0001), trabecular thickness by 2.6% (P < .001), and trabecular AS by 9.8% (P < .001). In contrast, testosterone treatment in all subjects significantly increased cortical thickness by 2.4% (P < .01) but decreased cortical BVF by -4.7% (P < .01) and cortical AS by -6.9% (P < .01).

CONCLUSION

Combined T and GH treatment of men with hypopituitarism for 2 years did not improve the measured structural or mechanical parameters of the distal tibia more than T alone. However, testosterone significantly increased the structural and mechanical properties of trabecular bone but decreased most of these properties of cortical bone, illustrating the potential importance of assessing trabecular and cortical bone separately in future studies of the effect of testosterone on bone.

Effects of recombinant human growth hormone therapy on bone mineral density in adults with growth hormone deficiency: a meta-analysis

OBJECTIVE

GH deficiency is associated with decreased bone mineral density (BMD) and increased fracture risk. Because the effects of recombinant human GH (rhGH) therapy on BMD and bone mineral content have not been systematically investigated, we conducted a meta-analysis of pertinent studies.

DESIGN

A thorough search of the literature (MEDLINE, EMBASE, and the Cochrane Register) was performed. Relevant studies were divided and analyzed according to their design (randomized/controlled or prospective/retrospective) and duration of rhGH therapy (≤12 months and > 12 months).

RESULTS

Administration of rhGH led to a significant increase in lumbar spine (LS) and femoral neck (FN) BMD in randomized/controlled studies of more than 1 year [weighted mean difference (95% confidence interval)] of 0.038 g/cm(2) (0.011-0.065) and 0.021 g/cm(2) (0.006-0.037) at the LS and FN, respectively, and a nonsignificant drop at the same sites in studies of shorter duration. In prospective studies, a significant increase in the LS and FN BMD was obtained. On meta-regression, a negative association was observed between the change in LS and FN BMD and subjects' age and a positive association between the BMD change and treatment duration. In a subgroup analysis, the increase in LS and FN BMD was significant in men [0.048 g/cm(2) (0.033-0.064) and 0.051 g/cm(2) (0.003-0.098), respectively] but not in women.

CONCLUSION

This meta-analysis suggests a beneficial effect of rhGH replacement on BMD in adults with GH deficiency. This effect is affected by gender, age, and treatment duration. Larger studies are needed to evaluate the effect of rhGH on fracture risk.

Predictors of the effects of 4 years of growth hormone replacement on bone mineral density in patients with adult-onset growth hormone deficiency - a KIMS database analysis

OBJECTIVE

Growth hormone (GH) replacement may increase bone mineral density (BMD) in GH-deficient (GHD) adults. The goal of this study was to identify predictors of BMD response to GH replacement in GH naïve adults.

DESIGN AND MEASUREMENTS

This was a retrospective analysis of data extracted from KIMS (Pfizer International Metabolic Database), an international pharmacoepidemiological survey of adult GHD patients from 31 countries.

PATIENTS

A total of 231 GH naive adults were identified (115 women and 116 men) who had BMD measured on the same densitometer in the lumbar spine (LS) and/or femoral neck (FN) both at baseline and after 4 years of GH replacement.

RESULTS

After 4 years, there was a median (10th, 90th percentile) 4·6% (-5·2%, 12·2%) increase in LS BMD over baseline (P = 0·0001). There was a positive correlation between per cent change in LS BMD and age at the onset of pituitary disease (r = 0·25, P = 0·001). There was no change in FN BMD over baseline [0·0% (-7·3%, 8·5%)]. On multivariate analysis, older age at the onset of pituitary disease predicted a greater increase in LS BMD on GH replacement (r = 0·55, P < 0·0001).

CONCLUSIONS

In a population of GH naïve adults, GH replacement led to a significant increase in LS BMD over baseline, but no change in FN BMD. The potential for greater BMD improvement on GH replacement therapy in adults with disease of later onset should be considered when making treatment decisions in this patient population.

Adult growth hormone deficiency - benefits, side effects, and risks of growth hormone replacement

Deficiency of growth hormone (GH) in adults results in a syndrome characterized by decreased muscle mass and exercise capacity, increased visceral fat, impaired quality of life, unfavorable alterations in lipid profile and markers of cardiovascular risk, decrease in bone mass and integrity, and increased mortality. When dosed appropriately, GH replacement therapy (GHRT) is well tolerated, with a low incidence of side effects, and improves most of the alterations observed in GH deficiency (GHD); beneficial effects on mortality, cardiovascular events, and fracture rates, however, remain to be conclusively demonstrated. The potential of GH to act as a mitogen has resulted in concern over the possibility of increased de novo tumors or recurrence of pre-existing malignancies in individuals treated with GH. Though studies of adults who received GHRT in childhood have produced conflicting reports in this regard, long-term surveillance of adult GHRT has not demonstrated increased cancer risk or mortality.

Growth hormone treatment in boys with Duchenne muscular dystrophy and glucocorticoid-induced growth failure

This study evaluated efficacy and safety of growth hormone treatment in Duchenne muscular dystrophy boys with glucocorticoid-induced growth failure. We reviewed 39 consecutive boys (average age 11.5 years; 32 ambulatory) treated with growth hormone for 1 year during a four-year period. Boys were on long-term daily deflazacort or prednisone (mean duration 5 ± 2.2 years; dosing regimen prednisone 0.75 mg/kg/day equivalent). Primary outcomes were growth velocity and height-for-age z-scores (height SD) at 1 year. Height velocity increased from 1.3 ± 0.2 to 5.2 ± 0.4 cm/year on growth hormone (p<0.0001). Pre-growth hormone decline in height SD (-0.5 ± 0.2SD/year) stabilized at height SD -2.9 ± 0.2 on growth hormone (p<0.0001). The rate of weight gain was unchanged, at 2.8 ± 0.6 kg/year pre-growth hormone and 2.6 ± 0.7 kg/year at 1 year. Motor function decline was similar pre-growth hormone and at 1 year. Cardiopulmonary function was unchanged. Three experienced side effects. In this first comprehensive report of growth hormone in Duchenne muscular dystrophy, growth hormone improved growth at 1 year, without detrimental effects observed on neuromuscular and cardiopulmonary function.

A review of guidelines for use of growth hormone in pediatric and transition patients

Growth hormone (GH) is approved by the US Food and Drug Administration (FDA) for use in pediatric patients with disorders of growth failure or short stature and in adults with growth hormone deficiency (GHD) and HIV/AIDS wasting and cachexia. For pediatric patients, guidelines for the use of GH have been developed by several organizations that have identified specific criteria for initiating GH therapy for each FDA-approved indication. Guidelines for adults have also been developed and include recommendations for transition (adolescent) patients with GHD. These patients are often treated with GH as children but may require continued treatment as young adults to attain full skeletal mineralization and improve cardiovascular risk factors. Adult and pediatric guidelines are supported by efficacy and safety studies, which show that, when started at an early age, GH treatment can increase growth velocity and that GH is safe and well-tolerated. We summarize the guidelines that are available for all FDA-approved indications among pediatric and transition patients. Adherence to these guidelines will help to ensure that patients with disorders of growth failure or short stature receive the necessary therapy to increase linear growth and transition smoothly to healthy adulthood.

Peripheral bone mineral density in correlation to disease-related predisposing conditions in patients with multiple endocrine neoplasia type 1

BACKGROUND AND AIM

Patients with multiple endocrine neoplasia type 1 (MEN1) often have low bone mineral density (BMD) attributed to primary hyperparathyroidism (pHPT). However, in MEN1 patients, other endocrine dysfunctions and conditions such as hypercortisolism, hypogonadism, and GH deficiency due to pituitary manifestation, and surgery on the upper gastrointestinal tract may affect BMD.

SUBJECTS AND METHODS

In 23 patients with MEN1 (10 females, 13 males; 46±12 yr), BMD was determined by quantitative computed tomography at the forearm (pqCT), compared to a reference population and related to different conditions suspected to affect bone metabolism in MEN1.

RESULTS

In this cohort, Z-score for trabecular BMD was -0.85±1.18 and for total BMD -1.16±1.04. There was a similar trend towards lower BMD in uncontrolled hyperparathyroidism, hypercortisolism, hypogonadism/GH deficiency and the state after surgery at the upper gastrointestinal tract.

CONCLUSIONS

These data while confirming previous observations on reduced BMD in patients with MEN1, however, challenge its only or even predominant association with pHPT. Other conditions such as hypercortisolism, somatotrophic/ gonadotrophic pituitary insufficiency, and previous upper gastrointestinal surgery seem to be factors contributing to the risk of developing osteoporosis.

Fifteen years of GH replacement increases bone mineral density in hypopituitary patients with adult-onset GH deficiency

OBJECTIVE

Few studies have determined the effects of more than 5-10 years of GH replacement in adults on bone mineral content (BMC) and bone mineral density (BMD).

DESIGN/PATIENTS

In this prospective, single-centre, open-label study, the effects of 15 years of GH replacement on BMC and BMD, measured using dual-energy X-ray absorptiometry, were determined in 126 hypopituitary adults (72 men) with adult-onset GH deficiency (GHD). Mean age was 49.4 (range 22-74) years at the initiation of the study.

RESULTS

The mean initial GH dose of 0.63 (s.e.m. 0.03) mg/day was gradually lowered to 0.41 (0.01) mg/day after 15 years. The mean serum IGF1 SDS increased from -1.69 (0.11) at baseline to 0.63 (0.16) at the study end (P<0.001 vs baseline). The 15 years of GH replacement induced a sustained increase in total body BMC (+5%, P<0.001) and BMD (+2%, P<0.001). Lumbar (L2-L4) spine BMC increased by 9% (P<0.001) and BMD by 5% (P<0.001). In femur neck, a peak increase in BMC and BMD of 7 and 3%, respectively, was observed after 7 years (both P<0.001). After 15 years, femur neck BMC was 5% above the baseline value (P<0.01), whereas femur neck BMD had returned to the baseline level. In most variables, men had a more marked response to GH replacement than women.

CONCLUSIONS

Fifteen-year GH replacement in GHD adults induced a sustained increase in total body and lumbar (L2-L4) spine BMC and BMD. In femur neck, BMC and BMD peaked at 7 years and then decreased towards baseline values.

Long-acting pegylated human GH in children with GH deficiency: a single-dose, dose-escalation trial investigating safety, tolerability, pharmacokinetics and pharmacodynamics

OBJECTIVE

GH replacement therapy currently requires daily injections, which may be inconvenient and distressing for young patients. This study determined the safety, tolerability, pharmacokinetics and pharmacodynamics of escalating single doses of a pegylated GH (NNC126-0083) developed for once-weekly administration, in children with GH deficiency (GHD).

DESIGN AND METHODS

Thirty children (age ≥6 and ≤12 years, weight ≥16 kg) were randomised to NNC126-0083 or daily GH treatment. The subjects discontinued their daily GH treatment 7-9 days before receiving NNC126-0083 at 0.01, 0.02, 0.04 or 0.06 mg protein/kg (n=22) or seven once-daily doses of GH at 0.035 mg protein/kg (n=8).

RESULTS

NNC126-0083 was well tolerated, and no short-term safety or local tolerability issues were identified. After NNC126-0083 treatment, dose-dependent IGF1 increases were evident for maximum concentration (C(max)), but not area under the curve (AUC(0)(-)(168 h)). Mean values for IGF1 AUC(0)(-)(168 h)/168 h and C(max) were higher for GH than for NNC126-0083, although the difference was not statistically significant for cohort's 0.06 mg protein/kg. At 0.06 mg protein/kg, the resulting IGF1 response began subsiding at ∼3 days post-dose.

CONCLUSION

Single doses of long-acting NNC126-0083 were safe and well tolerated in children with GHD. Increased IGF1 levels were observed in all NNC126-0083 dose groups; however, a satisfactory once-weekly IGF1 profile was not reached within the NNC126-0083 dose levels administered.

Effects of risedronate and low-dose transdermal testosterone on bone mineral density in women with anorexia nervosa: a randomized, placebo-controlled study

CONTEXT

Anorexia nervosa is complicated by severe bone loss and clinical fractures. Mechanisms underlying bone loss in adults with anorexia nervosa include increased bone resorption and decreased formation. Estrogen administration has not been shown to prevent bone loss in this population, and to date, there are no approved, effective therapies for this comorbidity.

OBJECTIVE

To determine whether antiresorptive therapy with a bisphosphonate alone or in combination with low-dose transdermal testosterone replacement would increase bone mineral density (BMD) in women with anorexia nervosa.

DESIGN AND SETTING

We conducted a12-month, randomized, placebo-controlled study at a clinical research center.

STUDY PARTICIPANTS

Participants included 77 ambulatory women with anorexia nervosa.

INTERVENTION

Subjects were randomized to risedronate 35 mg weekly, low-dose transdermal testosterone replacement therapy, combination therapy or double placebo.

MAIN OUTCOME MEASURES

BMD at the spine (primary endpoint), hip, and radius and body composition were measured by dual-energy x-ray absorptiometry.

RESULTS

Risedronate increased posteroanterior spine BMD 3%, lateral spine BMD 4%, and hip BMD 2% in women with anorexia nervosa compared with placebo in a 12-month clinical trial. Testosterone administration did not improve BMD but increased lean body mass. There were few side effects associated with either therapy.

CONCLUSIONS

Risedronate administration for 1 yr increased spinal BMD, the primary site of bone loss in women with anorexia nervosa. Low-dose testosterone did not change BMD but increased lean body mass.

[Growth hormone therapy in adult patients: a review]

Growth hormone deficiency (GHD) can frequently be expected in hypopituitarism of adult patients. If GHD is proven by dynamic testing of the somatotrophic axis, growth hormone substitution is useful for improving quality of life, body composition, bone and lipid metabolism, and myocardial function according to the criteria of evidence-based medicine and is admitted by most national health authorities. There are no other reasonable indications for growth hormone treatment in adulthood.

Predictors of bone responsiveness to growth hormone (GH) replacement in adult GH-deficient patients

Growth hormone (GH) replacement in adulthood results in variable bone responses as a function of the gonadic hormonal milieu. We performed a retrospective analysis of a large cohort of adult males and females with confirmed GH deficiency (GHD) prior to treatment and during 3 years of replacement therapy. Potential confounders and effect modifiers were taken into account. Sixty-four adult patients with GHD (20 females and 44 males; mean age 34 years, range 18-64) were included in the analysis. GH replacement induced a different effect on bone in males compared to females. Bone mineral content increased in males and decreased in females at the lumbar spine, total femur, and femoral neck; bone mineral density showed a similar trend at the lumbar spine and femoral neck. There was no significant gender difference in bone area at any measured bone site. In both sexes we observed a similar trend for serum markers of bone remodeling. Sex predicted bone outcome on multivariate analysis, as did age, onset of GHD (childhood/adulthood), pretreatment bone mass, baseline body mass index (BMI), and BMI change during GH replacement. Serum IGF-I levels during treatment did not show any relationship with bone outcome at any measured site. This study confirms that bone responsiveness to GH replacement in adult GHD varies as a function of sex even after controlling for potential confounders and highlights the importance of other cofactors that may affect the interaction between GH replacement therapy and bone remodeling.

Pegylated long-acting human growth hormone possesses a promising once-weekly treatment profile, and multiple dosing is well tolerated in adult patients with growth hormone deficiency

BACKGROUND

Recombinant human GH (rhGH) replacement therapy in children and adults currently requires daily sc injections for several years or lifelong, which may be both inconvenient and distressing for patients. NNC126-0083 is a pegylated rhGH developed for once-weekly administration.

OBJECTIVES

Our objective was to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of multiple doses of NNC126-0083 in adult patients with GH deficiency (GHD).

SUBJECTS AND METHODS

Thirty-three adult patients with GHD, age 20-65 yr, body mass index 18.5-35.0 kg/m(2), and glycated hemoglobin of 8.0% or below. Fourteen days before randomization, subjects discontinued daily rhGH. NNC126-0083 (0.01, 0.02, 0.04, and 0.08 mg/kg) was given sc once weekly for 3 wk (NNC126-0083 for six subjects and placebo for two subjects). Blood samples were collected up to 168 h after the first and up to 240 h after the third dosing. Physical examination, antibodies, and local tolerability were assessed.

RESULTS

NNC126-0083 was well tolerated with no difference in local tolerability compared with placebo and with no signs of lipoatrophy. A more than dose-proportional exposure was observed at the highest NNC126-0083 dose (0.16 mg protein/kg). Steady-state pharmacokinetics seemed achieved after the second dosing. A clear dose-dependent pharmacodynamic response in circulating IGF-I levels was observed [from a predose mean (SD) IGF-I SD score of -3.2 (1.7) to peak plasma concentration of -0.5 (1.3), 1.6 (1.3), 2.1 (0.5), and 4.4 (0.9) in the four dose groups, respectively].

CONCLUSION

After multiple dosing of NNC126-0083, a sustained pharmacodynamic response was observed. NNC126-0083 has the potential to serve as an efficacious, safe, and well-tolerated once-weekly treatment of adult patients with GHD.

Childhood growth hormone deficiency, bone density, structures and fractures: scrutinizing the evidence

Childhood-onset growth hormone deficiency (GHD) is frequently perceived to cause low bone density, fractures and osteoporosis. This article critically reviews the evidence behind these perceptions. Inherent limitations of current bone imaging techniques have caused many artefacts and misconceptions about bone density and structure. Using appropriate size-corrections, bone density is normal in children and adults with isolated GHD. Cortical density, trabecular density and trabecular volume are normal when measured by peripheral quantitative computerized tomography and histomorphometry. The only verifiable deficit affects cortical thickness (periosteal expansion), both in human and animal studies. However, short limb bones cannot be expected to have an average-sized shaft, as bone elongation and widening could be proportionally impaired in GHD. In addition, GH and IGF-1 have indisputable anabolic actions not only on bone, but also on muscle tissue. In fact, compared with all other bone-related variables, muscle size is the lowest at diagnosis of GHD. During GH therapy, muscle enlargement precedes and exceeds any gain in bone mass. The mechanostat theory suggests that the GHD-induced deficit in muscle force secondarily causes low cortical thickness. There is no evidence that isolated childhood-onset GHD, or severe GH resistance, causes an increased fracture risk in children or adults. Only adults with organic hypopituitarism appear to have a slightly greater risk of fractures. Using current transition guidelines, short children and adults with GHD are at risk of being misdiagnosed with low bone mass and may consequently receive inappropriate treatment. As neither reports of increased fracture risk nor low bone density can stand up against scrutiny, these misconceptions should no longer influence clinical practice. In this respect, GHD should not be listed as a cause of osteoporosis in children and there is a need to review current transition guidelines.

Treatment of adult growth hormone deficiency: who, why and how? A review

Adult growth hormone deficiency (AGHD) is nowadays recognized as a distinct clinical entity and replacement therapy has become a standard practice. Reflecting on the accumulated evidence, questions nevertheless arise. Should all AGHD patients be treated? What dose of GH should be given and for how long? What are the real long-term benefits, in particular regarding life expectancy? if the diagnosis of severe GHD is firmly established and if there is no contra-indication (such as an active cancer or uncontrolled diabetes), it is worthwile initiating GH replacement therapy. Treatment can indeed correct the abnormal body composition, improve various adverse cardiovascular parameters and risk factors, increase muscle strength and bone mineral density and, although to a variable degree, improve the patient's quality of life and psychological well-being. Treatment should be started with very low doses to avoid side-effects related to fluid retention and should then be gradually titrated against IGF-I values, clinical response and individual tolerance.There is unfortunately no confirmed predictive factor for the overall therapeutic response in a given individual. Thus, the decision to whether or not pursue the therapy will depend on the ratio of perceived and expected benefits over cost and risks of treatment, as well as on the persistent motivation of the patient.

Growth hormone and bone

PURPOSE OF REVIEW

Description of recent progress in our understanding of growth hormone (GH) effects on bone.

RECENT FINDINGS

Growth hormone deficiency is associated with low bone mass in children and adults, in addition to its well established impact on growth. Although GH and insulin-like growth factor I have direct skeletal actions, it is also possible that disordered parathyroid hormone secretion or effect may mediate some of the deleterious consequences of GH deficiency on bone. The benefits of GH replacement on bone mineral density have been demonstrated in many studies, but it remains unclear whether these are consistent across patient subgroups. The impact of GH replacement on fracture risk has not been definitively established. The positive effects of GH administration on growth are well established in childhood-onset growth hormone deficiency, as well as in several other pediatric conditions. Data on investigational uses of GH are also presented.

SUMMARY

GH may have a relevant role in bone physiology and several disease states in addition to growth hormone deficiency. Although the salutary effects of GH replacement on bone growth and bone density are well characterized, additional studies are required to examine the impact of GH replacement on fracture risk as well as potential benefits in osteoporosis.

Growth hormone, insulin-like growth factors, and the skeleton

GH and IGF-I are important regulators of bone homeostasis and are central to the achievement of normal longitudinal bone growth and bone mass. Although GH may act directly on skeletal cells, most of its effects are mediated by IGF-I, which is present in the systemic circulation and is synthesized by peripheral tissues. The availability of IGF-I is regulated by IGF binding proteins. IGF-I enhances the differentiated function of the osteoblast and bone formation. Adult GH deficiency causes low bone turnover osteoporosis with high risk of vertebral and nonvertebral fractures, and the low bone mass can be partially reversed by GH replacement. Acromegaly is characterized by high bone turnover, which can lead to bone loss and vertebral fractures, particularly in patients with coexistent hypogonadism. GH and IGF-I secretion are decreased in aging individuals, and abnormalities in the GH/IGF-I axis play a role in the pathogenesis of the osteoporosis of anorexia nervosa and after glucocorticoid exposure.

Effect of growth hormone replacement on BMD in adult-onset growth hormone deficiency

To determine if replacement of GH improves BMD in adult-onset GHD, we administered GH in physiologic amounts to men and women with GHD. GH replacement significantly increased spine BMD in the men by 3.8%.

INTRODUCTION

Growth hormone (GH) deficiency (GHD) acquired in adulthood results in diminished BMD; the evidence that replacement of GH improves BMD is not conclusive. We therefore performed a randomized, placebo-controlled trial to determine whether GH replacement would increase lumbar spine BMD in a combined group of men and women with adult-onset GHD.

MATERIALS AND METHODS

We randomized 67 men and women to receive GH (n=33) or placebo (n=34) for 2 yr. The GH dose was initially 2 microg/kg body weight/d, increased gradually to a maximum of 12 microg/kg/d and adjusted to maintain a normal IGF-I concentration for age and sex. BMD was assessed before treatment and at 6, 12, 18, and 24 mo of treatment. Fifty-four subjects completed the protocol.

RESULTS

BMD of the lumbar spine in the entire group increased by 2.9 +/- 3.9% above baseline in the GH-treated subjects, which was significantly (p=0.037) greater than the 1.4 +/- 4.5% increase in the placebo-treated subjects. In a secondary analysis, spine BMD in GH-treated men increased 3.8 +/- 4.3% above baseline, which was significantly (p=0.001) greater than that in placebo-treated men (0.4 +/- 4.7%), but the change in GH-treated women was not significantly different from that in placebo-treated women. Treatment with GH did not increase total hip BMD more than placebo treatment after 2 yr.

CONCLUSIONS

We conclude that GH replacement in men who have adult-onset GHD improves their spine BMD, but we cannot draw any conclusions about the effect of GH replacement on spine BMD in women with adult-onset GHD.

Management of adult growth hormone deficiency

The management of adults who have severe growth hormone deficiency (GHD) includes its recognition in susceptible patients, including all subjects who have any form of hypothalamic pituitary disorder. This article also focuses on the overall management of adults who have hypopituitarism and severe GHD. This includes aspects of diagnosis and management of growth hormone replacement therapy and the current status of its long-term safety. Some special circumstances, including the pregnant woman who has hypopituitarism, are discussed.

Growth hormone supplementation in the elderly

The imminent rapid increase in numbers of aging adults will significantly impact society and the health system in the coming years. The imperative is to allow older adults to maintain their independence and health for as long as possible and to prevent the ravages of chronic diseases and disabilities or the development of frailty. Significant hormonal changes are observed with aging (eg, decline in growth hormone [GH]), and strikingly similar changes in body composition are seen in GH-deficient adults and during aging. This article reviews some of the studies describing the effects of GH and GH secretagogues on body composition and functionality in the elderly. In addition, safety concerns and the need for further controlled studies of these therapies in the elderly are discussed.

Ten-year GH replacement increases bone mineral density in hypopituitary patients with adult onset GH deficiency

There are few studies that have determined the effects of long-term GH replacement on bone mineral density (BMD) in GH-deficient (GHD) adults. In this study, the effects of 10 years of GH replacement on BMD were assessed in 87 GHD adults using dual energy X-ray absorptiometry (DEXA). The results show that GH replacement induced a sustained increase in BMD at all the skeletal sites measured.

INTRODUCTION

Little is known of the effect of more than 5 years of GH replacement therapy on bone metabolism in GHD adults.

PATIENTS AND METHODS

In this prospective, open-label, single-center study, which included 87 consecutive adults (52 men and 35 women; mean age of 44.1 (range 22-74) years) with adulthood onset GHD, the effect of 10 years of GH replacement on BMD was determined.

RESULTS

The mean initial dose of GH was 0.98 mg/day. The dose was gradually lowered and after 10 years the mean dose was 0.47 mg/day. The mean insulin-like growth factor-I (IGF-I) SDS increased from 1.81 at baseline to 1.29 at study end. The GH replacement induced a sustained increase in total, lumbar (L2-L4) and femur neck BMD, and bone mineral content (BMC) as measured by DEXA. The treatment response in IGF-I SDS was more marked in men, whereas women had a more marked increase in the total body BMC and the total body z-score. There was a tendency for women on estrogen treatment to have a larger increase in bone mass and density compared with women without estrogen replacement.

CONCLUSIONS

Ten years of GH replacement in hypopituitary adults induced a sustained, and in some variables even a progressive, increase in bone mass and bone density. The study results also suggest that adequate estrogen replacement is needed in order to have an optimal response in BMD in GHD women.

Evaluation and treatment of adult growth hormone deficiency: an Endocrine Society Clinical Practice Guideline

OBJECTIVE

The objective is to provide guidelines for the evaluation and treatment of adults with GH deficiency (GHD).

PARTICIPANTS

The chair of the Task Force was selected by the Clinical Guidelines Subcommittee of The Endocrine Society (TES). The chair selected five other endocrinologists and a medical writer, who were approved by the Council. One closed meeting of the group was held. There was no corporate funding, and members of the group received no remuneration.

EVIDENCE

Only fully published, peer-reviewed literature was reviewed. The Grades of Evidence used are outlined in the Appendix.

CONSENSUS PROCESS

Consensus was achieved through one group meeting and e-mailing of drafts that were written by the group with grammatical/style help from the medical writer. Drafts were reviewed successively by the Clinical Guidelines Subcommittee, the Clinical Affairs Committee, and TES Council, and a version was placed on the TES web site for comments. At each level, the writing group incorporated needed changes.

CONCLUSIONS

GHD can persist from childhood or be newly acquired. Confirmation through stimulation testing is usually required unless there is a proven genetic/structural lesion persistent from childhood. GH therapy offers benefits in body composition, exercise capacity, skeletal integrity, and quality of life measures and is most likely to benefit those patients who have more severe GHD. The risks of GH treatment are low. GH dosing regimens should be individualized. The final decision to treat adults with GHD requires thoughtful clinical judgment with a careful evaluation of the benefits and risks specific to the individual.

Growth hormone replacement is important for the restoration of parathyroid hormone sensitivity and improvement in bone metabolism in older adult growth hormone-deficient patients

Alterations in PTH circadian rhythm and PTH target-organ sensitivity exist in adult GH-deficient (AGHD) patients and may underlie the pathogenesis of AGHD-related osteoporosis. GH replacement (GHR) results in increased bone mineral density, but its benefit in AGHD patients over 60 yr old has been debated. To examine the effect of age on changes in PTH circadian rhythm and target-organ sensitivity after GHR, we recruited 22 AGHD patients (12 were <60 yr of age, and 10 were >60 yr of age). Half-hourly blood samples were collected for PTH, calcium, phosphate, nephrogenous cAMP (marker of renal PTH activity), type-I collagenbeta C-telopeptide (bone resorption marker), and procollagen type-I amino-terminal propeptide (bone formation marker) before and after 1, 3, 6, and 12 months of treatment with GHR. Significant PTH circadian rhythms were present in both age groups throughout the study. After GHR, PTH decreased and nephrogenous cAMP, adjusted calcium, and bone turnover markers increased in both groups, suggesting increased PTH target-organ sensitivity. In younger patients, the changes were significant after 1 month of GHR, but, in older patients, the changes were delayed until 3 months, with maximal changes at 12 months. Older AGHD patients derive benefit from GHR in terms of improvement in PTH sensitivity and bone metabolism. Their response appears delayed and may explain why previous studies have not shown a positive effect of GHR on bone mineral density in older AGHD patients.

A new sustained-release preparation of human growth hormone and its pharmacokinetic, pharmacodynamic and safety profile

OBJECTIVE

Adult GH replacement is currently given by daily subcutaneous (sc) injections. Recently, sustained-release (SR) preparations of GH have been developed, the preparations being characterized by a dominant early release, resulting in supraphysiological early GH peaks, and a rapid decline thereafter. We present data on a new SR GH preparation.

DESIGN

Phase I/II study of hGH-Biosphere(R) (SkyePharma AB, Malmo, Sweden), a new SR preparation of recombinant human GH in amylopectin microspheres coated with polylactide-coglycolide.

PATIENTS

Eight adults with severe, untreated GH deficiency (stimulated GH peaks between < 1 and 1.7 microg/l), aged 36.1 years (range 22-49 years) in good general health.

MEASUREMENTS

Pharmacokinetic (PK), pharmacodynamic (PD) and safety data over a period of 28 days.

RESULTS

The systemic and local tolerability of the drug was satisfactory, and no serious adverse events occurred. PK analysis showed a smaller early serum hGH peak followed by a broad sustained second peak of hGH (C(max) 1.20 microg/l at 7.2 days), and hGH levels were maintained above baseline for at least 14 days. The mean GH level never exceeded 1.1 microg/l, making the GH fluctuations comparable to continuous sc infusion. Resultant IGF-I concentrations were characterized by sustained elevation at a level near C(max) of 103 microg/l (at t(max) of 9.7 days), equal to an SD score of +0.8. IGF-I generation per administered GH was more efficient compared with reports of other SR preparations.

CONCLUSION

hGH-Biosphere(R) is a well-tolerated SR GH preparation with superior efficacy in achieving target IGF-I levels without causing supraphysiological GH concentrations. Our data suggest the suitability of this preparation for longer-term trials in adults with injection frequencies of no more than once every 2-3 weeks.

Growth hormone replacement for adult growth hormone deficiency

Growth hormone deficiency (GHD) in childhood causes growth retardation, short stature and significant impairment of adult height. Growth hormone (GH) has been given successfully to these children for > 40 years but only since the introduction of recombinant DNA technology, has enough GH been available for paediatric needs and also for other indications. Adults with pituitary disease and hypopituitarism commonly develop GHD. Adult GHD is associated with an array of body composition alterations and metabolic abnormalities, as well as impaired physical performance and psychological well-being. None of these abnormalities are pathogenic for GHD but they constitute a characteristic clinical syndrome. GH substitution for adult GHD has been approved since 1996 in the US and most Western countries and since then, the clinical experience with this novel therapeutic modality is exponentially increased. GH replacement in this population has resulted in considerable clinical benefits. This article reviews the therapeutic principles, available GH formulations and current treatment guidelines for adult patients with GHD.

Bone metabolism in relation to alterations in systemic growth hormone

Growth hormone (GH) has a major role in the maintenance of bone mass in adults by regulating bone remodeling through a complex interaction of circulating GH, insulin-like growth factors (IGFs), IGF binding protein (IGFBPs), and locally produced IGFs and IGFBPs, acting in an autocrine and paracrine way. In vitro data has greatly increased our understanding of GH and IGFs effects and regulation in bone cells under controlled conditions, and especially the molecular pathways involved. However, the GH-and type I IGF-receptor are present in many tissues and various systemic factors may potentially regulate local expression of IGFs and IGFBPs in the intact organism. The use of genetically altered mice has changed this and had a major impact on defining the role of IGFs in skeletal homeostasis, and especially the role of systemic IGF-I in the development and maintenance of the adult skeleton. The focus of this review is to describe recent work on the effect of GH/IGF on remodeling in the adult skeleton emphasizing on data obtained in patient populations (i.e. acromegaly, GH deficiency, postmenopausal osteoporosis) and experimental models (i.e. animals with genetically altered expression of different GH and IGF family members) characterized by different systemic levels of these proteins. The role of IGF-I as a coupling agent between resorption and bone formation through effects on osteoprotegerin (OPG) and receptor activator of NFkappaB ligand (RANKL) are also discussed.

Clinical effects of growth hormone on bone: a review

Growth hormone (GH) stimulates bone turnover. Deficiency of GH due to hypopituitarism is related to low bone mineral density and increased fracture risk. GH substitution increases and thus normalizes bone mineral density in these patients, which is one of a number of arguments for GH substitution in hypopituitarism. In contrast, a possible therapeutic use of GH in idiopathic osteoporosis and glucocorticoid-induced osteoporosis is speculative and not established. Reduction of osteoporosis risk is an argument brought up for a use of GH in healthy elderly persons (anti-aging medicine). However, since only very limited data are available yet, this cannot be based on scientific evidence, and there are important concerns about the safety of use of GH in healthy elderly persons.

Estrogen regulation of growth hormone action

GH plays a pivotal role in regulating body growth and development, which is modulated by sex steroids. A close interplay between estrogen and GH leads to attainment of gender-specific body composition during puberty. The physiological basis of the interaction is not well understood. Most previous studies have focused on the effects of estrogen on GH secretion. There is also strong evidence that estrogen modulates GH action independent of secretion. Oral but not transdermal administration of estrogen impairs the metabolic action of GH in the liver, causing a fall in IGF-I production and fat oxidation. This results in a loss of lean tissue and a gain of body fat in postmenopausal women and an impairment of GH effect in hypopituitary women on GH replacement. The negative metabolic sequelae are potentially important because of the widespread use of oral estrogen and estrogen-related compounds. Estrogen affects GH action at the level of receptor expression and signaling. More recently, estrogen has been shown to inhibit Janus kinase/signal transducer and activator of transcription signaling by GH via the induction of suppressor of cytokine signaling-2, a protein inhibitor for cytokine signaling. This represents a novel paradigm of steroid regulation of cytokine receptors and is likely to have significance for a diverse range of cytokine function.