Efficacy and tolerability of an individualized dosing regimen for adult growth hormone replacement therapy in comparison with fixed body weight-based dosing

Individual sensitivity to growth hormone replacement in adults

The metabolic actions of growth hormone (GH) last a lifetime and involve several physiological functions associated with the control of body composition, energy metabolism, water regulation, immune response, cardiovascular performance, physical and mental work. Adult patients with GH deficiency (GHD) present a constellation of clinical findings, which include increased total and visceral body fat, low bone and muscle mass, reduced muscle strength, impaired anaerobic physical capacity, unfavorable cardiovascular profile, and poor quality of life. Recombinant human GH (rhGH) therapy has been proved to reverse or improve many abnormalities associated with GHD in adult life, but the therapeutic response is highly variable among patients and influenced by multiple factors, which are the main focus of this narrative review. Given the individual sensitivity of adult GHD patients to rhGH replacement, dose regimens evolved from weight-based to individualized dose-titration strategies, which improved efficacy and reduced the frequency of adverse events. Individual tailoring and maintenance doses of rhGH are mainly influenced by age, age at GHD onset, sex, body mass index, baseline GH status, quality of life and other pituitary hormone replacements. In addition, genetic background and poor adherence due to patient or product-related factors might play a role in the responsiveness to rhGH therapy. There have been attempts to develop predictive mathematical models to distinguish good and poor responders to rhGH therapy, but thus far none of them have been prospectively tested and validated in a large cohort of adult GHD individuals.

Optimal Monitoring of Weekly IGF-I Levels During Growth Hormone Therapy With Once-Weekly Somapacitan

CONTEXT

Somapacitan is a long-acting growth hormone (GH) in development for once-weekly treatment of GH deficiency (GHD). Optimal monitoring of insulin-like growth factor-I (IGF-I) levels must account for weekly IGF-I fluctuations following somapacitan administration.

OBJECTIVE

To develop and assess the reliability of linear models for predicting mean and peak IGF-I levels from samples taken on different days after dosing.

DESIGN

A pharmacokinetic/pharmacodynamic model was used to simulate IGF-I data in adults and children following weekly somapacitan treatment of GHD.

SETTING AND PATIENTS

39 200 IGF-I profiles were simulated with reference to data from 26 adults and 23 children with GHD.

INTERVENTION(S)

The simulated dose range was 0.02 to 0.12 mg/kg for adults and 0.02 to 0.16 mg/kg for children. Simulated data with >4 average standard deviation score were excluded.

MAIN OUTCOME MEASURE(S)

Linear models for predicting mean and peak IGF-I levels based on IGF-I samples from different days after somapacitan dose.

RESULTS

Robust linear relationships were found between IGF-I sampled on any day after somapacitan dose and the weekly mean (R2 > 0.94) and peak (R2 > 0.84). Prediction uncertainties were generally low when predicting mean from samples taken on any day (residual standard deviation [RSD] ≤ 0.36) and peak from samples taken on day 1 to 4 (RSD ≤ 0.34). IGF-I monitoring on day 4 and day 2 after dose provided the most accurate estimate of IGF-I mean (RSD < 0.2) and peak (RSD < 0.1), respectively.

CONCLUSIONS

Linear models provided a simple and reliable tool to aid optimal monitoring of IGF-I by predicting mean and peak IGF-I levels based on an IGF-I sample following dosing of somapacitan. A short visual summary of our work is available (1).

Diagnosis and Treatment of Growth Hormone Deficiency: A Position Statement from Korean Endocrine Society and Korean Society of Pediatric Endocrinology

Growth hormone (GH) deficiency is caused by congenital or acquired causes and occurs in childhood or adulthood. GH replacement therapy brings benefits to body composition, exercise capacity, skeletal health, cardiovascular outcomes, and quality of life. Before initiating GH replacement, GH deficiency should be confirmed through proper stimulation tests, and in cases with proven genetic causes or structural lesions, repeated GH stimulation testing is not necessary. The dosing regimen of GH replacement therapy should be individualized, with the goal of minimizing side effects and maximizing clinical improvements. The Korean Endocrine Society and the Korean Society of Pediatric Endocrinology have developed a position statement on the diagnosis and treatment of GH deficiency. This position statement is based on a systematic review of evidence and expert opinions.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY GUIDELINES FOR MANAGEMENT OF GROWTH HORMONE DEFICIENCY IN ADULTS AND PATIENTS TRANSITIONING FROM PEDIATRIC TO ADULT CARE

Objective: The development of these guidelines is sponsored by the American Association of Clinical Endocrinologists (AACE) Board of Directors and American College of Endocrinology (ACE) Board of Trustees and adheres with published AACE protocols for the standardized production of clinical practice guidelines (CPG). Methods: Recommendations are based on diligent reviews of clinical evidence with transparent incorporation of subjective factors, according to established AACE/ACE guidelines for guidelines protocols. Results: The Executive Summary of this 2019 updated guideline contains 58 numbered recommendations: 12 are Grade A (21%), 19 are Grade B (33%), 21 are Grade C (36%), and 6 are Grade D (10%). These detailed, evidence-based recommendations allow for nuance-based clinical decision-making that addresses multiple aspects of real-world care of patients. The evidence base presented in the subsequent Appendix provides relevant supporting information for the Executive Summary recommendations. This update contains 357 citations of which 51 (14%) are evidence level (EL) 1 (strong), 168 (47%) are EL 2 (intermediate), 61 (17%) are EL 3 (weak), and 77 (22%) are EL 4 (no clinical evidence). Conclusion: This CPG is a practical tool that practicing endocrinologists and regulatory bodies can refer to regarding the identification, diagnosis, and treatment of adults and patients transitioning from pediatric to adult-care services with growth hormone deficiency (GHD). It provides guidelines on assessment, screening, diagnostic testing, and treatment recommendations for a range of individuals with various causes of adult GHD. The recommendations emphasize the importance of considering testing patients with a reasonable level of clinical suspicion of GHD using appropriate growth hormone (GH) cut-points for various GH-stimulation tests to accurately diagnose adult GHD, and to exercise caution interpreting serum GH and insulin-like growth factor-1 (IGF-1) levels, as various GH and IGF-1 assays are used to support treatment decisions. The intention to treat often requires sound clinical judgment and careful assessment of the benefits and risks specific to each individual patient. Unapproved uses of GH, long-term safety, and the current status of long-acting GH preparations are also discussed in this document. LAY ABSTRACT This updated guideline provides evidence-based recommendations regarding the identification, screening, assessment, diagnosis, and treatment for a range of individuals with various causes of adult growth-hormone deficiency (GHD) and patients with childhood-onset GHD transitioning to adult care. The update summarizes the most current knowledge about the accuracy of available GH-stimulation tests, safety of recombinant human GH (rhGH) replacement, unapproved uses of rhGH related to sports and aging, and new developments such as long-acting GH preparations that use a variety of technologies to prolong GH action. Recommendations offer a framework for physicians to manage patients with GHD effectively during transition to adult care and adulthood. Establishing a correct diagnosis is essential before consideration of replacement therapy with rhGH. Since the diagnosis of GHD in adults can be challenging, GH-stimulation tests are recommended based on individual patient circumstances and use of appropriate GH cut-points. Available GH-stimulation tests are discussed regarding variability, accuracy, reproducibility, safety, and contraindications, among other factors. The regimen for starting and maintaining rhGH treatment now uses individualized dose adjustments, which has improved effectiveness and reduced reported side effects, dependent on age, gender, body mass index, and various other individual characteristics. With careful dosing of rhGH replacement, many features of adult GHD are reversible and side effects of therapy can be minimized. Scientific studies have consistently shown rhGH therapy to be beneficial for adults with GHD, including improvements in body composition and quality of life, and have demonstrated the safety of short- and long-term rhGH replacement. Abbreviations: AACE = American Association of Clinical Endocrinologists; ACE = American College of Endocrinology; AHSG = alpha-2-HS-glycoprotein; AO-GHD = adult-onset growth hormone deficiency; ARG = arginine; BEL = best evidence level; BMD = bone mineral density; BMI = body mass index; CI = confidence interval; CO-GHD = childhood-onset growth hormone deficiency; CPG = clinical practice guideline; CRP = C-reactive protein; DM = diabetes mellitus; DXA = dual-energy X-ray absorptiometry; EL = evidence level; FDA = Food and Drug Administration; FD-GST = fixed-dose glucagon stimulation test; GeNeSIS = Genetics and Neuroendocrinology of Short Stature International Study; GH = growth hormone; GHD = growth hormone deficiency; GHRH = growth hormone-releasing hormone; GST = glucagon stimulation test; HDL = high-density lipoprotein; HypoCCS = Hypopituitary Control and Complications Study; IGF-1 = insulin-like growth factor-1; IGFBP = insulin-like growth factor-binding protein; IGHD = isolated growth hormone deficiency; ITT = insulin tolerance test; KIMS = Kabi International Metabolic Surveillance; LAGH = long-acting growth hormone; LDL = low-density lipoprotein; LIF = leukemia inhibitory factor; MPHD = multiple pituitary hormone deficiencies; MRI = magnetic resonance imaging; P-III-NP = procollagen type-III amino-terminal pro-peptide; PHD = pituitary hormone deficiencies; QoL = quality of life; rhGH = recombinant human growth hormone; ROC = receiver operating characteristic; RR = relative risk; SAH = subarachnoid hemorrhage; SDS = standard deviation score; SIR = standardized incidence ratio; SN = secondary neoplasms; T3 = triiodothyronine; TBI = traumatic brain injury; VDBP = vitamin D-binding protein; WADA = World Anti-Doping Agency; WB-GST = weight-based glucagon stimulation test.

Biomarkers of GH action in children and adults

Growth hormone (GH) and IGF-I levels in serum are used as biomarkers in the diagnosis and management of GH-related disorders but have not been subject to structured validation. Auxological parameters in children and changes in body composition in adults, as well as metabolic parameters and patient related outcomes are used as clinical and surrogate endpoints. New treatment options, such as long acting GH and GH antagonists, require reevaluation of the currently used biochemical biomarkers. This article will review biomarkers, surrogate endpoints and clinical endpoints related to GH treatment in children and adults as well as in acromegaly.

Oral glucose-stimulated growth hormone (GH) test in adult GH deficiency patients and controls: Potential utility of a novel test

CONTEXT

The diagnosis of adult GH deficiency requires confirmation with a GH stimulation test. Oral glucose (OG) administration affects GH secretion, initially decreasing and subsequently stimulating GH secretion.

OBJECTIVE

The aim of this study was to investigate the diagnostic efficacy and safety of a long OG test (LOGT) as a stimulus of GH secretion for the diagnosis of adult GH deficiency (AGHD).

DESIGN

Prospective experimental cross-sectional study.

SETTINGS

The study was conducted at the Endocrinology department of the University Hospital of a Coruña, Spain.

PARTICIPANTS AND METHODS

We included 60 (40 women) AGHD patients (15) and controls (45) paired 1:3, of similar age, sex and BMI. The area under the curve (AUC) and peak were calculated for GH. The Mann-Whitney test was used to compare the different groups. ROC curve analyses were used. p-Values<0.05 were considered as statistically significant.

INTERVENTIONS

The intervention consisted of orally administering 75g oral glucose administration; GH was obtained every 30min for a total of 300min.

MAIN OUTCOME MEASUREMENT

Peak GH area under receiver operating characteristic curve (ROC-AUC) following LOGT.

RESULTS

Peak GH (μg/L) levels were lower in the AGHD patients (0.26±0.09) than in the controls (4.00±0.45), p<0.001. After LOGT, with the ROC plot analysis the best peak GH cut-point was 1.0μg/L, with 100% sensitivity, 78% specificity, ROC-AUC of 0.9089 and 81.82% accuracy. There were no relevant adverse events during any of the LOGT.

CONCLUSIONS

The LOGT could be a cheap, safe, convenient and effective test for the diagnosis of AGHD.

A phase 2 trial of long-acting TransCon growth hormone in adult GH deficiency

TransCon growth hormone is a sustained-release human growth hormone prodrug under development in which unmodified growth hormone is transiently linked to a carrier molecule. It is intended as an alternative to daily growth hormone in the treatment of growth hormone deficiency. This was a multi-center, randomized, open-label, active-controlled trial designed to compare the safety (including tolerability and immunogenicity), pharmacokinetics and pharmacodynamics of three doses of weekly TransCon GH to daily growth hormone (Omnitrope). Thirty-seven adult males and females diagnosed with adult growth hormone deficiency and stable on growth hormone replacement therapy for at least 3 months were, following a wash-out period, randomized (regardless of their pre-study dose) to one of three TransCon GH doses (0.02, 0.04 and 0.08 mg GH/kg/week) or Omnitrope 0.04 mg GH/kg/week (divided into 7 equal daily doses) for 4 weeks. Main outcomes evaluated were adverse events, immunogenicity and growth hormone and insulin-like growth factor 1 levels. TransCon GH was well tolerated; fatigue and headache were the most frequent drug-related adverse events and reported in all groups. No lipoatrophy or nodule formation was reported. No anti-growth hormone-binding antibodies were detected. TransCon GH demonstrated a linear, dose-dependent increase in growth hormone exposure without accumulation. Growth hormone maximum serum concentration and insulin-like growth factor 1 exposure were similar after TransCon GH or Omnitrope administered at comparable doses. The results suggest that long-acting TransCon GH has a profile similar to daily growth hormone but with a more convenient dosing regimen. These findings support further TransCon GH development.

MOD-4023, a long-acting carboxy-terminal peptide-modified human growth hormone: results of a Phase 2 study in growth hormone-deficient adults

OBJECTIVE

Growth hormone (GH) replacement therapy currently requires daily injections, which may cause distress and low compliance. C-terminal peptide (CTP)-modified growth hormone (MOD-4023) is being developed as a once-weekly dosing regimen in patients with GH deficiency (GHD). This study's objective is to evaluate the safety, pharmacokinetics (PK), pharmacodynamics (PD) and efficacy of MOD-4023 administered once-weekly in GHD adults.

DESIGN

54 adults with GHD currently treated with daily GH were normalized and randomized into 4 weekly dosing cohorts of MOD-4023 at 18.5%, 37%, 55.5% or 123.4% of individual cumulative weekly molar hGH dose. The study included 2 stages: Stage A assessed the effectiveness and PK/PD profiles of the 4 dosing regimens of MOD-4023. Stage B was an extension period of once-weekly MOD-4023 administration (61.7% molar hGH content) to collect further safety data and confirm the results from Stage A.

RESULTS

Dose-dependent response was observed for both PK and PD data of weekly MOD-4023 treatment. Insulin-like growth factor I (IGF-I) SDS levels were maintained within normal range. The 18.5% cohort was discontinued due to low efficacy. MOD-4023 was well tolerated and exhibited favorable safety profile in all dose cohorts. The reported adverse events were consistent with known GH-related side effects.

CONCLUSIONS

Once-weekly MOD-4023 administration in GHD adults was found to be clinically effective while maintaining a favorable safety profile and may obviate the need for daily injections. Weekly GH injections may improve compliance and overall outcome. The promising results achieved in this Phase 2 study led to a pivotal Phase 3 trial, which is currently ongoing.

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.

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.

Computerized advice on drug dosage to improve prescribing practice

BACKGROUND

Maintaining therapeutic concentrations of drugs with a narrow therapeutic window is a complex task. Several computer systems have been designed to help doctors determine optimum drug dosage. Significant improvements in health care could be achieved if computer advice improved health outcomes and could be implemented in routine practice in a cost-effective fashion. This is an updated version of an earlier Cochrane systematic review, first published in 2001 and updated in 2008.

OBJECTIVES

To assess whether computerized advice on drug dosage has beneficial effects on patient outcomes compared with routine care (empiric dosing without computer assistance).

SEARCH METHODS

The following databases were searched from 1996 to January 2012: EPOC Group Specialized Register, Reference Manager; Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Ovid; EMBASE, Ovid; and CINAHL, EbscoHost. A "top up" search was conducted for the period January 2012 to January 2013; these results were screened by the authors and potentially relevant studies are listed in Studies Awaiting Classification. The review authors also searched reference lists of relevant studies and related reviews.

SELECTION CRITERIA

We included randomized controlled trials, non-randomized controlled trials, controlled before-and-after studies and interrupted time series analyses of computerized advice on drug dosage. The participants were healthcare professionals responsible for patient care. The outcomes were any objectively measured change in the health of patients resulting from computerized advice (such as therapeutic drug control, clinical improvement, adverse reactions).

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed study quality. We grouped the results from the included studies by drug used and the effect aimed at for aminoglycoside antibiotics, amitriptyline, anaesthetics, insulin, anticoagulants, ovarian stimulation, anti-rejection drugs and theophylline. We combined the effect sizes to give an overall effect for each subgroup of studies, using a random-effects model. We further grouped studies by type of outcome when appropriate (i.e. no evidence of heterogeneity).

MAIN RESULTS

Forty-six comparisons (from 42 trials) were included (as compared with 26 comparisons in the last update) including a wide range of drugs in inpatient and outpatient settings. All were randomized controlled trials except two studies. Interventions usually targeted doctors, although some studies attempted to influence prescriptions by pharmacists and nurses. Drugs evaluated were anticoagulants, insulin, aminoglycoside antibiotics, theophylline, anti-rejection drugs, anaesthetic agents, antidepressants and gonadotropins. Although all studies used reliable outcome measures, their quality was generally low.This update found similar results to the previous update and managed to identify specific therapeutic areas where the computerized advice on drug dosage was beneficial compared with routine care:1. it increased target peak serum concentrations (standardized mean difference (SMD) 0.79, 95% CI 0.46 to 1.13) and the proportion of people with plasma drug concentrations within the therapeutic range after two days (pooled risk ratio (RR) 4.44, 95% CI 1.94 to 10.13) for aminoglycoside antibiotics;2. it led to a physiological parameter more often within the desired range for oral anticoagulants (SMD for percentage of time spent in target international normalized ratio +0.19, 95% CI 0.06 to 0.33) and insulin (SMD for percentage of time in target glucose range: +1.27, 95% CI 0.56 to 1.98);3. it decreased the time to achieve stabilization for oral anticoagulants (SMD -0.56, 95% CI -1.07 to -0.04);4. it decreased the thromboembolism events (rate ratio 0.68, 95% CI 0.49 to 0.94) and tended to decrease bleeding events for anticoagulants although the difference was not significant (rate ratio 0.81, 95% CI 0.60 to 1.08). It tended to decrease unwanted effects for aminoglycoside antibiotics (nephrotoxicity: RR 0.67, 95% CI 0.42 to 1.06) and anti-rejection drugs (cytomegalovirus infections: RR 0.90, 95% CI 0.58 to 1.40);5. it tended to reduce the length of time spent in the hospital although the difference was not significant (SMD -0.15, 95% CI -0.33 to 0.02) and to achieve comparable or better cost-effectiveness ratios than usual care;6. there was no evidence of differences in mortality or other clinical adverse events for insulin (hypoglycaemia), anaesthetic agents, anti-rejection drugs and antidepressants.For all outcomes, statistical heterogeneity quantified by I(2) statistics was moderate to high.

AUTHORS' CONCLUSIONS

This review update suggests that computerized advice for drug dosage has some benefits: it increases the serum concentrations for aminoglycoside antibiotics and improves the proportion of people for which the plasma drug is within the therapeutic range for aminoglycoside antibiotics.It leads to a physiological parameter more often within the desired range for oral anticoagulants and insulin. It decreases the time to achieve stabilization for oral anticoagulants. It tends to decrease unwanted effects for aminoglycoside antibiotics and anti-rejection drugs, and it significantly decreases thromboembolism events for anticoagulants. It tends to reduce the length of hospital stay compared with routine care while comparable or better cost-effectiveness ratios were achieved.However, there was no evidence that decision support had an effect on mortality or other clinical adverse events for insulin (hypoglycaemia), anaesthetic agents, anti-rejection drugs and antidepressants. In addition, there was no evidence to suggest that some decision support technical features (such as its integration into a computer physician order entry system) or aspects of organization of care (such as the setting) could optimize the effect of computerized advice.Taking into account the high risk of bias of, and high heterogeneity between, studies, these results must be interpreted with caution.

Clinical characteristics and effects of GH replacement therapy in adults with childhood-onset craniopharyngioma compared with those in adults with other causes of childhood-onset hypothalamic-pituitary dysfunction

OBJECTIVE

Adults with childhood-onset (CO) craniopharyngioma (COCP) have poor quality of life (QoL) and clinical outcomes, but few studies have compared these patients with adults with other causes of CO hypothalamic-pituitary dysfunction. In this study, we compared baseline clinical characteristics and patient-reported outcomes before starting GH replacement therapy in adults with GH deficiency (GHD) due to COCP with those of adults either with CO idiopathic/congenital hypopituitarism (COH) or with CO extrasellar (COE) tumours, and evaluated the 1- and 5-year effects of GH replacement therapy.

SUBJECTS AND METHODS

Retrospective analysis of the data recorded in KIMS (Pfizer International Metabolic Database) was carried out. Patients with COCP, COH and COE tumours were evaluated at baseline, and after 1 and 5 years of therapy.

RESULTS

Compared with COH and COE patients, more COCP patients underwent surgery, had greater abnormalities of body composition and higher prevalence of pituitary hormone deficits (all P<0.001), but comparable fasting glucose, HbA1c, total cholesterol and LDL-cholesterol levels, marital status, parenthood, living arrangements, education, employment and annual sick-leave days. After 1 and 5 years of GH replacement therapy, similar changes were evident with regard to body composition, fasting glucose and HbA1c levels, QoL, and the level of and satisfaction with physical activity across the three groups.

CONCLUSIONS

Adults with untreated COCP with GHD at baseline demonstrated more co-morbidities including greater abnormalities of body composition, pituitary hormone deficits and visual field defects. Overall, adults with COCP, COH and COE tumours responded comparably to short- and long-term GH replacement therapy, suggesting that patients with GHD due to COCP benefited from GH replacement therapy to a similar degree as those with other causes of CO hypothalamic-pituitary dysfunction did.

12-month effects of once-weekly sustained-release growth hormone treatment in adults with GH deficiency

The weekly sustained-release recombinant human GH formulation LB03002, showed beneficial effects in GH-deficient (GHD) adults in a previous 26-week double-blind study. Prior studies of long-acting GH preparations in adults have only been conducted for 6 or 8 months, so the effects of longer-term use are unknown; this is important to address, as replacement is given for many years in GHD adults. This open-label, 26-week study extension evaluated longer-term safety and efficacy of LB03002 over 52 weeks in adults with GHD who had previously been randomized to GH, and provides additional safety and efficacy data over 26 weeks in the cohort who had previously been randomized to placebo. Of 147 adults with GHD who completed a preceding study, 136 patients continued in this open-label study to receive LB03002 over an additional 26 weeks. This represented a continuation of long-acting GH for 26 weeks in the cohort who took this medication in the prior study (LB03002 Throughout group), and describes the first use of long-acting GH in the cohort that was randomized to placebo in the prior study (Switched to LB03002 group). The LB03002 dose was adjusted according to serum insulin-like growth factor-I (IGF-I) levels. LB03002 treatment demonstrated mean significant decreases from baseline in fat mass (FM) for both 26 (Switched group, P = 0.001) and 52 weeks (Throughout group, P = 0.002) of 1.11 (1.95) kg and 1.06 (3.16) kg, respectively. Prolonged GH treatment was effective in sustaining the increase in lean body mass (LBM), serum IGF-I and IGFBP-3 levels achieved during the first 26 weeks. Long-term treatment with the sustained-release weekly GH preparation over both 26 and 52 weeks in adults with GHD demonstrated a sustained reduction of FM with a favorable safety profile. This study extends prior knowledge about long-acting GH because it reports the most prolonged treatment of adults with any long-acting GH preparation, thereby confirming the value and safety of such agents for long-term GH replacement.

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.

A long-acting human growth hormone with delayed clearance (VRS-317): results of a double-blind, placebo-controlled, single ascending dose study in growth hormone-deficient adults

BACKGROUND

Administration of daily recombinant human GH (rhGH) poses a considerable challenge to patient compliance. Reduced dosing frequency may improve treatment adherence and potentially overall treatment outcomes.

OBJECTIVES

This study assessed the safety and tolerability and the potential for achieving IGF-I levels within the target range in adults with GH deficiency after a single dose of the long-acting rhGH analog, VRS-317.

DESIGN

This was a randomized, double-blind, placebo-controlled, single ascending dose study.

PATIENTS

Fifty adults with growth hormone deficiency (mean age, 45 years) were studied in 5 treatment groups of 10 subjects each (8 active drug and 2 placebo).

SETTING

The study was conducted in 17 adult endocrinology centers in North America and Europe.

MAIN OUTCOME MEASURES

Adverse events, laboratory safety assessments, and VRS-317 pharmacokinetics and pharmacodynamics (IGF-I and IGF binding protein-3) were analyzed.

RESULTS

At 0.80 mg/kg, VRS-317 had a mean terminal elimination half-life of 131 hours. Single VRS-317 doses of 0.05, 0.10, 0.20, 0.40, and 0.80 mg/kg (approximately equivalent to daily rhGH doses of 0.3-5.0 μg/kg over 30 d) safely increased the amplitude and duration of IGF-I responses in a dose-dependent manner. After a single 0.80 mg/kg dose, serum IGF-I was maintained in the normal range between -1.5 and 1.5 SD values for a mean of 3 weeks. No unexpected or serious adverse events were observed.

CONCLUSIONS

The elimination half-life for VRS-317 is 30- to 60-fold longer and stimulates more durable IGF-I responses than previously studied rhGH products. Prolonged IGF-I responses do not come at the expense of overexposure to high IGF-I levels. The pharmacokinetics and pharmacodynamics combined with the observed safety profile indicate the potential for safe and effective monthly dosing.

Changes in pituitary function with ageing and implications for patient care

The pituitary gland has a role in puberty, reproduction, stress-adaptive responses, sodium and water balance, uterine contractions, lactation, thyroid function, growth, body composition and skin pigmentation. Ageing is marked by initially subtle erosion of physiological signalling mechanisms, resulting in lower incremental secretory-burst amplitude, more disorderly patterns of pituitary hormone release and blunted 24 h rhythmic secretion. Almost all pituitary hormones are altered by ageing in humans, often in a manner dependent on sex, body composition, stress, comorbidity, intercurrent illness, medication use, physical frailty, caloric intake, immune status, level of exercise, and neurocognitive decline. The aim of this article is to critically discuss the mechanisms mediating clinical facets of changes in the hypothalamic-pituitary axis during ageing, and the extent to which confounding factors operate to obscure ageing-related effects.

GH therapy in adult GH deficiency: a review of treatment schedules and the evidence for low starting doses

Recombinant human GH has been licensed for use in adult patients with GH deficiency (GHD) for over 15 years. Early weight- and surface area-based dosing regimens were effective but resulted in supraphysiological levels of IGF1 and increased incidence of side effects. Current practice has moved towards individualised regimens, starting with low GH doses and gradually titrating the dose according to the level of serum IGF1 to achieve an optimal dose. Here we present the evidence supporting the dosing recommendations of current guidelines and consider factors affecting dose responsiveness and parameters of treatment response. The published data discussed here lend support for the use of low GH dosing regimens in adult GHD. The range of doses defined as 'low dose' in the studies discussed here (∼1-4  mg/week) is in accordance with those recommended in current guidelines and encompasses the dose range recommended by product labels.

How useful are serum IGF-I measurements for managing GH replacement therapy in adults and children?

The optimal dosing of growth hormone (GH) therapy is challenging due to high inter-individual variability in subcutaneous GH absorption and sensitivity to the drug. Optimal dosing would maximize patient gains in height, body composition, and metabolic outcomes while minimizing GH adverse events. The pulsatile secretion of GH, however, does not allow direct assessment of circulating GH levels as a measure of response to GH therapy. Insulin-like growth factor (IGF-I), a key marker of GH activity, has been shown to be useful in monitoring and adjusting GH dose during treatment of GH deficiency (GHD). Traditionally, monitoring IGF-I levels in response to GH therapy has been recommended for assessment of treatment compliance and safety. More recently, GH treatment guidelines have stated that IGF-I levels should also be used to guide GH dosing. This review examines whether individualized GH dosing based on the IGF-I response to GH therapy provides a better method for determining the GH replacement needs of pediatric and adult patients compared with conventional GH dosing, and whether IGF-I-based dosing improves outcomes such as height and body composition, with reduced side effects. Because IGF-I measurement presents its own difficulties, the current state of IGF-I assays is also discussed. The reviewed studies show that the use of GH dose adjustments based on IGF-I responses to GH therapy successfully reduces adverse events in adults with GHD and results in greater positive height attainment in children, without increasing adverse events. Long-term outcome studies are needed, as are internationally accepted guidelines for IGF-I measurement.

Optimized clinical performance of growth hormone with an expanded genetic code

The ribosomal incorporation of nonnative amino acids into polypeptides in living cells provides the opportunity to endow therapeutic proteins with unique pharmacological properties. We report here the first clinical study of a biosynthetic protein produced using an expanded genetic code. Incorporation of p-acetylphenylalanine (pAcF) at distinct locations in human growth hormone (hGH) allowed site-specific conjugation with polyethylene glycol (PEG) to produce homogeneous hGH variants. A mono-PEGylated mutant hGH modified at residue 35 demonstrated favorable pharmacodynamic properties in GH-deficient rats. Clinical studies in GH-deficient adults demonstrated efficacy and safety comparable to native human growth hormone therapy but with increased potency and reduced injection frequency. This example illustrates the utility of nonnative amino acids to optimize protein therapeutics in an analogous fashion to the use of medicinal chemistry to optimize conventional natural products, low molecular weight drugs, and peptides.

The diagnosis and treatment of growth hormone deficiency in adults

PURPOSE OF REVIEW

This review summarizes the recent published information regarding efficacy and complications of growth hormone replacement therapy. Several recent reports have monitored patients for periods of up to 10 years. Additionally, a consensus conference has been held regarding needed improvements in diagnostic testing and the recommendations of consensus panels regarding diagnostic criteria and laboratory test utilization are summarized.

RECENT FINDINGS

Long-term studies show growth hormone can be administered safely and that muscle strength and function as well as lipoprotein abnormalities and low-bone mineral density show sustained improvement over extended periods of time. The complications that occur are generally dose-dependent and once attenuated do not tend to recur. Long-term safety studies regarding improvement in cardiovascular mortality and/or worsening prognosis for patients who develop malignancies are available only in the form of observational studies and randomized controlled long-term trial information is not yet available. The studies reported provide a means for clinicians to ascertain the patients who are likely to derive the greatest benefit from growth hormone when the appropriate diagnostic testing and treatment paradigms are utilized.

SUMMARY

The studies that are summarized provide useful information for assessing the response to treatment, selecting patients who are candidates for long-term replacement therapy and for selecting those in whom the need for therapy may need to be reassessed.

The value of IGF1 estimation in adults with GH deficiency

The GH/IGF1 system, like other endocrine systems, is dynamic and its activity changes with age and sexual maturation, and is influenced by body composition and other factors. A normal level of IGF1 does not exclude a diagnosis of GH deficiency (GHD) in adults, and the usefulness of IGF1 in the diagnosis of adult GHD has historically been confusing and contentious. The regulation of IGF1 secretion in adults is complex, and is not solely dependent on GH status with factors recognized to influence IGF1 status in patients with GHD including age, gender, exogenous estrogen therapy, prolactin status, and severity of GHD. The usefulness of IGF1 for monitoring treatment of GH disorders in adulthood is now widely accepted, especially as GH-dosing regimens for GHD have evolved from weight-based dosing (associated with overtreatment and side effects) to individualized dose-titration strategies, which maintain IGF1 within target limits. Sub-optimal replacement therapy may be associated with morbidity and mortality risk from a continuing state of functional GHD. Conversely, avoiding iatrogenic biochemical acromegaly is clearly important and other potential safety issues may be associated with a persistently high IGF1. Analysis and interpretation of IGF1 status therefore represent a useful diagnostic tool especially in the younger adult patients with severe GHD and an essential measurement for monitoring GH replacement in all adults with GHD. High-quality, method-specific reference ranges for IGF1 and a high degree of methodological consistency in the assay are essential for reliable comparison of results.

Efficacy and safety of individualized growth hormone treatment in adult Japanese patients with growth hormone deficiency

OBJECTIVE

The aim of the study was to evaluate the efficacy and safety of growth hormone (GH) treatment in Japanese adult patients with GH-deficiency. In the extension of the efficacy study, the effect of individualized-dosing (ID), based on insulin-like growth factor-I (IGF-I) levels, and fixed-dose (FD) GH regimens on body composition, were compared in Japanese GH-deficient adults.

DESIGN

Randomized, double-blind (DB), placebo-controlled, 24-week treatment period followed by 48-week, open-label study in 43 endocrinology clinics in Japan. Patients received DB treatment with GH (0.012 mg/kg/day; n=57) or placebo (n=60) followed by open-label GH in an ID (n=75) or FD (0.012 mg/kg/day; n=38) regimen.

SUBJECTS

Adult Japanese GH-deficient patients (peak GH<3 ng/mL).

MEASUREMENTS

Trunk and total body fat (BF), lean body mass (LBM), and adverse events were determined.

RESULTS

Percentage trunk fat was reduced significantly more in GH- than in placebo-treated patients at 24 weeks (-16.2 vs. 1.7%, p<0.0001). Open-label treatment with an ID or FD GH regimen provided similar reductions in percentage trunk fat (-8.12 vs. -9.35%), and total BF (-0.92 vs. -0.70 kg) and a comparable increase in LBM (1.032 vs. 0.97 kg). Mean+/-SD GH doses (mg/kg/day) at 48 weeks were significantly lower with the ID GH regimen (ID, 0.0082+/-0.0050; FD, 0.0095+/-0.0033; p<0.05). The safety profile was comparable between ID and FD groups.

CONCLUSIONS

Treatment with GH was associated with a significant reduction in trunk fat and improvement in serum lipid profile in Japanese adult GH-deficient patients. The improvement in body composition and tolerability were comparable between ID and FD GH regimens despite a significantly lower daily GH dose with the ID regimen.

Guidelines for the treatment of growth hormone excess and growth hormone deficiency in adults

The V Consensus Group Meeting on 'Guidelines for Treatment of GH Excess and GH Deficiency in the Adult' was an international workshop held on February 20-22, 2006 in Santa Monica, California, USA. The principal aim of this meeting was to provide guidelines for the evaluation and treatment of adults with either form of abnormal GH secretion: GH excess or GH deficiency. The workshop included debates as to the choice of primary treatment, discussions of the targets for adequate treatment, and concluded with presentations on open issues germane to adult GH treatment including the role of GH in malignancies, the impact of longterm treatment on bone, and a cost-benefit analysis. The meeting was comprised of 66 delegates representing 13 different countries.

Safety and efficacy of growth hormone (GH) during extended treatment of adult Japanese patients with GH deficiency (GHD)

OBJECTIVES

To assess the effects of a growth hormone (GH) replacement therapy using a GH dose regimen based on serum insulin-like growth factor (IGF-I) concentrations in Japanese adults with GH deficiency (GHD).

DESIGN

In this multicentre, uncontrolled, open-label study, Japanese adults with GHD who had received either GH replacement therapy (GH-GH group, n=35) or placebo (Placebo-GH group, n=36) in a previous randomised, double-blind, placebo-controlled trial were treated with GH replacement therapy for 48 weeks. GH treatment was started at a dose of 0.003 mg/kg/day administered by subcutaneous injection for the first 8 weeks, after which the dose was adjusted to maintain patients' serum IGF-I levels within the reference range adjusted for age and gender. Body composition, serum lipids, serum IGF-I and IGF binding protein-3 (IGFBP-3) levels were measured throughout study. Symptom and quality of life scores were also determined.

RESULTS

Lean body mass (LBM) was increased compared with baseline (the end of the preceding double-blind trial) at 24 and 48 weeks, with a mean (+/-SD) increase of 1.3% (+/-4.2%) at week 48 in the GH-GH group (an increase of 6.6% [+/-6.0%] from the start of the preceding double-blind trial) and a larger increase of 4.7% (+/-5.9%) in the Placebo-GH group. Body fat mass (BFM) increased slightly from baseline in the GH-GH group with a mean increase of 2.9+/-10.6% at week 48 (a decrease from the start of the preceding double-blind trial at 48 weeks of 7.8% [+/-15.0%]) but decreased by 6.5% (+/-11.7%) at week 48 in the Placebo-GH group. Serum lipids were unchanged or slightly increased from baseline in the GH-GH group but patients' lipid profiles improved in the Placebo-GH group. In patients who received placebo during the double-blind study, individualised GH therapy in this open-label study increased mean LBM at 48 weeks by 6.2+/-6.8% in patients with CO GHD and by 3.0+/-4.4% in patients with AO GHD. Changes in mean LBM and mean BFM at week 48 were +4.1+/-4.5% and -2.4+/-10.5%, respectively, in females and +5.0+/-6.7% and -8.9+/-11.8%, respectively, in males. In patients who received GH treatment during the double-blind study, overall changes in LBM, BFM and IGF-I SD score after 24 weeks and 48 weeks were small, with no significant differences between subgroups. While the overall incidence of adverse events was broadly similar in the GH-GH and Placebo-GH groups (97% and 89%, respectively), the incidence of treatment-related events was higher in the GH-GH group (83% vs 42% in the Placebo-GH group). Most adverse events in both treatment groups were of mild or moderate severity and not clinically significant. The incidences of oedema and cases of high IGF-I during the IGF-I level-adjusted treatment regimen were lower than those during the preceding fixed dose titration.

CONCLUSION

Long-term GH replacement therapy was well tolerated in Japanese adults with GHD. GH treatment maintained the improvements in body composition and lipid profiles in the patients previously treated in the double-blind study (GH-GH group) and improved these parameters in previously untreated patients (Placebo-GH group). Individualised GH administration based on IGF-I levels was well-tolerated and effective.

Growth hormone replacement therapy in adults with growth hormone deficiency improves maximal oxygen consumption independently of dosing regimen or physical activity

CONTEXT

Several studies have demonstrated an improvement in aerobic exercise capacity with 6 months of GH replacement in adults with GH deficiency (GHD).

OBJECTIVE

The objective of the study was to determine whether improvements in aerobic exercise capacity with GH treatment in adults with GHD are related to changes in physical activity or affected by the GH dosing regimen.

DESIGN

This was a randomized, two-arm, parallel, open-label study.

SETTING

The study was conducted at five academic medical centers with exercise physiology laboratories.

SUBJECTS

Study subjects were adults (n = 29) with GHD due to hypothalamic-pituitary disease.

INTERVENTIONS

The intervention was GH replacement therapy, administered either as a fixed body weight-based dosing regimen as an individualized dose titration regimen for 32 wk.

MAIN OUTCOME MEASURES

Maximal oxygen consumption (VO2 max) and oxygen consumption (VO2) at the lactate threshold, ventilatory threshold using a cycle ergometry protocol, and weekly energy expenditure (physical activity questionnaire), assessed at baseline and end point, were measured.

RESULTS

In the group as a whole, VO2 max increased significantly (by 9%) from baseline (19.1+/- 0.89 ml/kg.min) to end point (21.6 +/- 1.23 ml/kg.min, P = 0.010). Compared with baseline, VO2 max also changed significantly within the individualized dose titration regimen group (+2.5 +/- 0.98 ml/kg.min, P =0.034) but not within the fixed body weight-based dosing regimen group (+1.2 +/- 0.78 ml/kg.min, P = 0.15), although these changes from baseline were not significantly different between the two groups. VO2 at lactate threshold, VO2 at ventilatory threshold, and weekly energy expenditure also did not change.

CONCLUSIONS

GH replacement therapy in GH-deficient adults improved VO2 max similarly with both dosing regimens, without any influence of physical activity. There was no effect on submaximal exercise performance.

Abuse of growth hormone among young athletes

The underground abuse of growth hormone (GH) among young athletes presents a challenge to medical professionals. Health care professionals providing knowledgeable guidance regarding healthy ways to improve performance and appearance, as well as accurate information regarding substances' perceived benefits, risks, and unknown qualities, is invaluable to the young athlete. Further research focused on the profile and motivation of young people who use GH is essential to understanding and intervening better with those who use these substances.

Insulin growth factor-based dosing of growth hormone therapy in children: a randomized, controlled study

CONTEXT

Weight-based dosing of GH is the standard of care for short children, although IGF-I is thought to be the main mediator of GH actions on growth.

OBJECTIVE

The objective of the study was to test whether IGF-I levels achieved during GH therapy are determinants of the growth responses to GH treatment.

DESIGN

This was a 2-yr, open-label, randomized, IGF-I concentration-controlled trial. Prepubertal short children [n = 172, mean age 7.53 yr, mean height sd score (HT-SDS) -2.64] with low IGF-I levels (mean IGF-I SDS -3.56) were randomized to receive one of two GH dose-titration arms in which GH dosage was titrated to achieve an IGF-I SDS at the mean [IGF((low)) group, n = 70] or the upper limit of the normal range [+2 SDS, IGF((high)) group, n = 68] or to a comparison group of conventional GH dose of 40 microg/kg/d (n = 34).

SETTING

The study was conducted in a multicenter, outpatient setting.

PRIMARY OUTCOME MEASURE

Change in HT-SDS over 2 yr was measured.

RESULTS

One hundred forty-seven patients completed the trial. Target IGF-I levels were achieved in the dose-titration arms within 6-9 months. The changes in HT-SDS were +1.0, +1.1, and +1.6 for conventional, IGF((low)), and IGF((high)), respectively, with IGF((high)) showing significantly greater linear growth response (P < 0.001, compared with the other two groups). The IGF((high)) arm required higher doses (>2.5 times) than the IGF((low)) arm, and these GH doses were highly variable (20-346 microg/kg/d). Multivariate analyses suggested that the rise in the IGF-I SDS significantly impacted height outcome along with the GH dose and the pretreatment peak-stimulated GH level.

CONCLUSION

IGF-I-based GH dosing is clinically feasible and allows maintaining serum IGF-I concentrations within the desired target range. Titrating the GH dose to achieve higher IGF-I targets results in improved growth responses, although at higher average GH doses.

IGF-I measurements in the monitoring of GH therapy

Growth hormone replacement therapy has been used regularly in adult Growth hormone deficiency since the availability of recombinant GH in the 1980's. GH replacement improves quality of life, bone turnover markers, cardiovascular risk markers and adverse body composition. Originally, GH doses in replacement regimes were determined by weight and surface area and dose increases based on body composition outcomes analogous to pediatric practice. These regimens led to significant side effects related to excess GH, arthralgias, headaches and peripheral edema and IGF-I levels above the upper limit of the reference range. Newer treatment regimes therefore account for known factors affecting serum GH and IGF-I levels, i.e. age, gender, estrogen replacement and pre-treatment IGF-I levels. Monitoring is now via clinical symptomatology combined with serum total IGF-I levels, potentially this avoids excessive GH exposure and allows monitoring of compliance and dose titration. There is a lack of data relating IGF-I to biological endpoints, but analysis suggests that dose titration of IGF-I to the upper half of the age and gender related reference range is acceptable. The use of reliable IGF-I assays and extensive age and gender related reference ranges is necessary and centralized monitoring is preferable. Free IGF-I and bioavailable IGF-I measurements are available but their use in the monitoring of GH replacement remains to be determined.

Anterior pituitary hormone replacement therapy--a clinical review

This clinical review summarizes current approaches to diagnosis and treatment of anterior pituitary hormone deficiency. The diagnostic value of endocrine function tests and replacement strategies for hydrocortisone, thyroxine, sex steroids, and growth hormone replacement are reviewed. Female androgen deficiency syndrome and the current role of DHEA and testosterone replacement in women are also discussed.

Provocative stimulation of growth hormone: a monozygotic twin study discordant for spinal cord injury

BACKGROUND/OBJECTIVE

A blunted growth hormone (GH) response to provocative testing and/or low levels of plasma insulin-like growth factor-I (IGF-I) have been reported in persons with spinal cord injury (SCI). A reduction in activity of the GH-IGF-I axis may have deleterious effects on body composition and function. Provocative testing for GH stimulation was performed to determine the response in monozygotic twins that were discordant for SCI.

METHODS

GH stimulation testing was performed by the administration of intravenous arginine.

RESULTS

Nine SCI twins with paraplegia, a mean age of 39 +/- 9 years, and duration of injury of 14 +/- 9 years were studied. The twins with SCI had a significantly lower body mass index than non-SCI twins (22.5 +/- 4.0 vs 25.1 +/- 4.2 kg/m2; P < 0.05); percent fat mass was greater in the twins with SCI (30 +/- 11% vs 22 +/- 10%; P < 0.05). Baseline serum GH was correlated with percent fat only in the SCI twins. The response to GH provocative stimulation was less in the twins with SCI: peak GH response was 5.8 +/- 6.6 vs 13.0 +/- 7.3 ng/mL (P < 0.05), and sum GH response was 15.7 +/- 15.6 vs 30.2 +/- 17.3 ng/mL (P = 0.06). Although baseline serum GH was correlated with stimulated response in the SCI twins, this relationship was not found in the non-SCI twins. Adiposity was positively related to the provocative serum GH response in twins with SCI rather than negatively related, as noted in the non-SCI twins.

CONCLUSIONS

This study confirms and extends prior work that reported a reduction in stimulated GH release in persons with SCI, which was related to baseline values.

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.

An individualized GH dose regimen for long-term GH treatment in Japanese patients with adult GH deficiency

OBJECTIVES

To investigate the effects of growth hormone (GH) treatment, using a dose-adjustment regimen based on serum insulin-like growth factor (IGF)-I concentrations, in adult Japanese hypopituitary patients with GH deficiency.

STUDY DESIGN

Japanese patients who had initially been administered GH (n = 31) or placebo (n = 28) in a 24-week double-blind study received individualized GH treatment in an open-label study for 48 weeks. Body composition from dual-energy X-ray absorptiometry (DXA) and serum IGF-I, IGF-binding protein 3 (IGFBP-3) and lipid levels were determined centrally.

RESULTS

Significant increases in lean body mass (4.5%) and decreases in fat mass (-10.5%) were observed in the group that received individualized GH doses in the present open-label study following placebo in the double-blind study. This was comparable with the changes observed in these parameters (4.7 and -9.2%, respectively) with fixed-dose GH treatment in the double-blind study; this latter group maintained these improvements throughout the open-label study. Individualized dose adjustment allowed for more moderate dose increases than the fixed-dose titration method. Individualized dosing also resulted in a lower mean dose for adult-onset compared with childhood-onset GH-deficient patients (0.032+/-0.019 versus 0.061+/-0.023 mg/kg per week for patients treated with GH for 48 weeks in the open-label study following placebo in the double-blind study). Dosing patterns in the two groups were paralleled by the changes in IGF-I and IGFBP-3. The incidence of oedema and cases with high IGF-I level were less frequent under the IGF-I controlled regimen compared with those during the fixed-dose titration method.

CONCLUSION

Individualized GH administration based on IGF-I levels was safe and effective. This regimen demonstrated differences in dose requirements between adult- and childhood-onset patients. An individualized dose regimen is recommended in adult Japanese GH-deficient patients.

Treatment of the adult growth hormone deficiency syndrome: directions for future research

The adult growth hormone deficiency syndrome (AGHD) is a well-defined clinical entity characterized by decreased lean body mass and bone mineral density, increased visceral adiposity, abnormal lipid profile, decreased muscle strength and exercise endurance, and diminished quality of life. Recent studies have emphasized the increased morbidity and mortality of hypopituitary patients, and there are now data implicating growth hormone (GH) deficiency as a cause of this increase. GH replacement therapy has been shown to reverse many of these abnormalities and to be well tolerated. Meta-analyses have demonstrated that GH treatment positively affects cardiovascular risk factors, and controlled trials have shown that visceral adiposity decreases in treated patients. Improvements in bone mineral density and decreases in fracture rates have also been reported, and new studies using disease-specific questionnaires provide convincing evidence that GH greatly enhances quality of life. Epidemiologic studies indicate that higher insulin-like growth factor I (IGF-I) levels may predict risk for certain cancers, but other studies suggest that lower IGF-I levels increase risk for ischemic heart disease. However, much of the community of endocrine caregivers remains skeptical of GH treatment and, therefore, a large fraction of patients with AGHD are not treated. The accumulation of long-term treatment data will be required to provide reassurance that GH treatment is a safe and necessary form of hormone replacement therapy for patients with AGHD.

One year of GH replacement therapy with a fixed low-dose regimen improves body composition, bone mineral density and lipid profile of GH-deficient adults

OBJECTIVE

We have studied the effects on body composition and metabolism of a fixed low dose of growth hormone (GH), 0.6 IU (0.2 mg)/day, administered for 12 months to GH-deficient (GHD) adults.

DESIGN AND METHODS

Prospective open-label study, using 18 GHD patients (11 women, 7 men; aged 21-58 years). All investigations were performed at baseline and after 12 months. Body composition was determined by dual energy X-ray absorptiometry.

RESULTS

Total body fat decreased (-1.74+/-2.87%) and lean body mass (LBM) increased (1.27+/-2.08 kg) after therapy (P < 0.05). Changes in truncal fat did not reach statistical significance, but a decrease varying from 0.72 to 2.78kg (1 to 8.7%) was observed in 13 (72%) patients. Bone mineral density (BMD) increased at lumbar spine, total femur and femoral neck (P < 0.05). Levels of total and low-density lipoprotein (LDL)-cholesterol were lower after therapy (P < 0.05), and their changes were directly associated with values at baseline. Insulin levels increased and the insulin resistance index worsened at 12 months (P < 0.05). Median IGF-I s.d. score was -4.30 (range, -11.03 to -0.11) at baseline and -1.73 (range, -9.80 to 2.26) at 12 months. Normal age-adjusted IGF-I levels were obtained with therapy in 5 of 11 patients who had low IGF-I levels at baseline. Changes in IGF-I levels were not correlated with any biological end point, except changes in LBM (r = 0.53, P = 0.02). Side effects were mild and disappeared spontaneously.

CONCLUSIONS

One-year of a fixed low-dose GH regimen in GHD adults resulted in a significant reduction in body fat, total cholesterol and LDL-cholesterol, and a significant increase in LBM and BMD at lumbar spine and femur, regardless of normalization of IGF-I levels. This regimen led to an elevation of insulin levels and a worsening of the insulin resistance index.

Le questionnaire de qualité de vie QLS-H© : validation de la version française chez les patients avec déficit en hormone de croissance et acquisition des valeurs de référence dans la population générale

The QLS-H(c) (Questions on Life Satisfaction- Hypopituitarism) is new a quality of life (QoL) self-administered questionnaire addressing the complaints of adult patients with growth hormone deficiency. The French version of the QLS-H(c) (16 items) has been psychometrically evaluated during a randomized, open label study comparing two strategies of growth hormone (GH) replacement therapy. Seventy-three patients were included and received an 8-month GH replacement therapy. QoL was explored at baseline, 4 and 8 months using the QLS-H(c) questionnaire and the Nottingham Health Profile (NHP) reference scale. Acceptance of the QLS-H(c) was excellent as 92% of the questionnaires were suitable for analysis. All the items demonstrated good selectivity. The homogeneity of the questionnaire was confirmed (Cronbach's alpha, 0.87). The external validity construct was assessed and confirmed using the NHP scores. Sensitivity to change was confirmed. Following an 8-month replacement therapy, the perception of the QoL assessed with the QLS-H(c) questionnaire was significantly improved, irrespective to the treatment strategy. Finally, redundant items of the questionnaire were removed. As a result, the final version of the QLS-H(c) contained 9 items. In a parallel study, reference data of the QLS-H(c) (9 items) were collected from a representative sample of 989 subjects from the French population. With these reference ranges, algorithms to calculate Z scores adjusted for age and gender were developed as a measure for the deviation of patients' scores from those of the general population, and also to evaluate changes along time. In summary, the French version of the quality of life QLS-H(c) questionnaire is a relevant, validated investigational tool for the evaluation and follow-up of an adult patient with growth hormone deficiency.