Status of long-acting-growth hormone preparations--2015

Approach to the Patient: Case Studies in Pediatric Growth Hormone Deficiency and Their Management

CONTEXT

Pathologies attributed to perturbations of the GH/IGF-I axis are among the most common referrals received by pediatric endocrinologists.

AIM

In this article, distinctive cased-based presentations are used to provide a practical and pragmatic approach to the management of pediatric growth hormone deficiency (GHD).

CASES

We present 4 case vignettes based on actual patients that illustrate (1) congenital GHD, (2) childhood GHD presenting as failure to thrive, (3) childhood GHD presenting in adolescence as growth deceleration, and (4) childhood-onset GHD manifesting as metabolic complications in adolescence. We review patient presentation and a management approach that aims to highlight diagnostic considerations for treatment based on current clinical guidelines, with mention of new therapeutic and diagnostic modalities being used in the field.

CONCLUSION

Pediatric GHD is diverse in etiology and clinical presentation. Timely management has the potential not only to improve growth but can also ameliorate or even mitigate adverse metabolic outcomes, which can be directly attributed to a GH deficient state.

Growth hormone receptor agonists and antagonists: From protein expression and purification to long-acting formulations

Recombinant human growth hormone (rhGH) and GH receptor antagonists (GHAs) are used clinically to treat a range of disorders associated with GH deficiency or hypersecretion, respectively. However, these biotherapeutics can be difficult and expensive to manufacture with multiple challenges from recombinant protein generation through to the development of long-acting formulations required to improve the circulating half-life of the drug. In this review, we summarize methodologies and approaches used for making and purifying recombinant GH and GHA proteins, and strategies to improve pharmacokinetic and pharmacodynamic properties, including PEGylation and fusion proteins. Therapeutics that are in clinical use or are currently under development are also discussed.

Evaluation of efficacy and safety of long-acting PEGylated recombinant human growth hormone (Jintrolong) for patients with growth hormone deficiency

OBJECTIVES

This study aimed to compare the efficacy, safety and metabolic effects of once-weekly pegylated human growth hormone (PEG-rhGH) with daily rhGH in patients with growth hormone deficiency (GHD).

DESIGN

48 patients enrolled in this 12-month single-center, open-label, prospective, randomized controlled trial is allocated to PEG-rhGH 0.12 mg/kg/w and 0.20 mg/kg/w treatment. Besides, the control group allocated 23 patients treated with daily rhGH 0.28 mg/kg/w matched with sex, age, and baseline IGF-1 levels. The primary endpoint included height velocity (HV) and IGF-1 increase at the end of treatment. Other parameters associated with growth, metabolism and safety were also monitored.

RESULTS

In terms of HV increase, the efficacy of PEG-rhGH dosed at 0.12 mg/kg/w and 0.20 mg/kg/w was comparable to that of daily rhGH dosed at 0.28 mg/kg/w after 3, 6 and 12 treatment (p>0.05). IGF-1 concentration and IGF-1 SDS were both elevated significantly at 3, 6 and 12 months (p=0.000) into normal range following PEG-rhGH treatment. BMI SDS elevated after PEG-rhGH treatment for 3, 6 and 12 months (p=0.000). HbA1c elevated after 3 and 12 months (p=0.009) and METS-IR elevated after 6 months (p=0.019) compared with baseline. The differences of other metabolic indexes (such as blood glucose, blood lipid, etc.) have no statistical significance (p>0.05). No severe adverse event was observed among the three groups.

CONCLUSIONS

The efficacy and safety were promising and comparable between once-weekly PEG-rhGH and daily rhGH injection within 12 months. The negative influence on glucose homeostasis needed attention and monitoring.

Effective GH Replacement With Once-weekly Somapacitan vs Daily GH in Children with GHD: 3-year Results From REAL 3

CONTEXT

Current GH therapy requires daily injections, which can be burdensome. Somapacitan is a long-acting GH derivative in development for treatment of GH deficiency (GHD).

OBJECTIVE

Evaluate the efficacy, safety, and tolerability of once-weekly somapacitan after 3 years of treatment.

DESIGN

A multicenter, randomized, controlled, phase 2 study comparing somapacitan and once-daily GH for 156 weeks (NCT02616562).

SETTING

Twenty-nine sites in 11 countries.

PATIENTS

Fifty-nine children with GHD randomized (1:1:1:1) and exposed to treatment. Fifty-three children completed the 3-year period.

INTERVENTIONS

Patients received somapacitan (0.04 [n = 14], 0.08 [n = 15], or 0.16 [n = 14] mg/kg/wk) or daily GH (n = 14) (0.034 mg/kg/d, equivalent to 0.238 mg/kg/wk) subcutaneously during the first year, after which all patients on somapacitan received 0.16 mg/kg/wk.

MAIN OUTCOME MEASURES

Height velocity (HV) at year 3; changes from baseline in height SD score (HSDS), HVSDS, and IGF-I SDS.

RESULTS

The estimated treatment difference (95% CI) in HV for somapacitan 0.16/0.16 mg/kg/wk vs daily GH at year 3 was 0.8 cm/y (-0.4 to 2.1). Change in HVSDS from baseline to year 3 was comparable between somapacitan 0.16/0.16 mg/kg/wk, the pooled somapacitan groups, and daily GH. A gradual increase in HSDS from baseline was observed for all groups. At year 3, mean HSDS was similar for the pooled somapacitan groups and daily GH. Change from baseline to year 3 in mean IGF-I SDS was similar across treatments.

CONCLUSIONS

Once-weekly somapacitan in children with GHD showed sustained efficacy over 3 years in all assessed height-based outcomes with similar safety and tolerability to daily GH. A plain language summary (1) is available for this study.

CLINICAL TRIAL INFORMATION

This study has been registered at ClinicalTrials.gov, number NCT02616562 (REAL 3).

Rahman N, Wong TW, Chee CF. Challenges and Complications of Poly(lactic-co-glycolic acid)-Based Long-Acting Drug Product Development

Poly(lactic-co-glycolic acid) (PLGA) is one of the preferred polymeric inactive ingredients for long-acting parenteral drug products that are constituted of complex formulations. Despite over 30 years of use, there are still many challenges faced by researchers in formulation-related aspects pertaining to drug loading and release. Until now, PLGA-based complex generic drug products have not been successfully developed. The complexity in developing these generic drug products is not just due to their complex formulation, but also to the manufacturing process of the listed reference drugs that involve PLGA. The composition and product attributes of commercial PLGA formulations vary with the drugs and their intended applications. The lack of standard compendial methods for in vitro release studies hinders generic pharmaceutical companies in their efforts to develop PLGA-based complex generic drug products. In this review, we discuss the challenges faced in developing PLGA-based long-acting injectable/implantable (LAI) drug products; hurdles that are associated with drug loading and release that are dictated by the physicochemical properties of PLGA and product manufacturing processes. Approaches to overcome these challenges and hurdles are highlighted specifically with respect to drug encapsulation and release.

PEGylated Recombinant Human Growth Hormone Jintrolong® Exhibits Good Long-Term Safety in Cynomolgus Monkeys and Human Pediatric Growth Hormone Deficiency Patients

Jintrolong^® is a long-acting PEGylated recombinant human growth hormone (PEG-rhGH) developed for weekly injection in patients with pediatric growth hormone deficiency (PGHD). Although PEG modification of therapeutic proteins is generally considered safe, concerns persist about the potential for adverse vacuolation in tissues with long-term exposure to PEG-included therapies, particularly in children. We assessed the safety of Jintrolong^® in cynomolgus monkeys with an examination of vacuolation in the brain choroid plexus (CP) and reported long-term clinical safety data obtained from children with PGHD. The toxicity of Jintrolong^® was assessed following the 52-week administration with doses at 0.3, 1, or 3 mg/kg/week. The levels of vacuolation of CP in animals were dose-dependent and at least partially reversible after a 104- or 157-week recovery period. Vacuolation in the CP epithelium did not lead to obvious subcellular structural or cell functional abnormalities. Compared with the clinical dose of 0.2 mg/kg/week Jintrolong^® in PGHD patients, exposure in monkeys under NOAEL 3 mg/kg/week exhibited safety margins greater than 120.5, the predicted minimum dose to induce vacuolation in monkeys is equivalent to 1.29 mg/kg/week in humans, which is 6.45-fold higher than the clinical dose. The safety data acquired in clinical trials for Jintrolong^® were also analyzed, which included phase III (360 patients), phase IV (3,000 patients) of 26-week treatment, and a follow-up study with treatment lasting for 3 years. There was no statistically significant difference in the incidence of adverse reactions between the Jintrolong^® group and the daily rhGH control group (no PEG), and no new adverse effects (AE) were observed in the Jintrolong^® group at the clinical therapeutic dose of 0.2 mg/kg/week.

Effect of Weekly Long-Acting Growth Hormone Replacement Therapy Compared to Daily Growth Hormone on Children With Short Stature: A Meta-Analysis

Background

We performed a meta-analysis to evaluate the efficacy and safety of weekly long-acting growth hormone replacement therapy compared to daily growth hormone in children with short stature.

Methods

A systematic literature search up to April 2021 was performed and 11 studies included 1,232 children with short stature treated with growth hormone replacement therapy at the start of the study; 737 of them were using weekly long-acting growth hormone replacement therapy and 495 were using daily growth hormone. They were reporting relationships between the efficacy and safety of long-acting growth hormone replacement therapy and daily growth hormone in children with short stature. We calculated the odds ratio (OR), and mean difference (MD) with 95% confidence intervals (CIs) to assess the efficacy and safety of weekly long-acting growth hormone replacement therapy compared to daily growth hormone in children with short stature using the dichotomous or continuous method with a random or fixed-effect model.

Results

Long-acting growth hormone replacement therapy had significantly lower height standard deviation scores chronological age (MD, -0.10; 95% CI, -0.13 to -0.08, p <0.001), and insulin-like growth factor binding protein-3 (MD, -0.69; 95% CI, -1.09 to -0.30, p <0.001) compared to daily growth hormone in children with short stature.However, growth hormone replacement therapy had no significantly difference in height velocity (MD, -0.09; 95% CI, -0.69-0.5, p = 0.76), height standard deviation scores bone age (MD, -0.04; 95% CI, -0.10-0.02, p = 0.16), insulin-like growth factor 1 standard deviation scores (MD, 0.26; 95% CI, -0.26-0.79, p = 0.33), and incidence of adverse events (OR, 1.16; 95% CI, 0.90-1.50, p = 0.25) compared to daily growth hormone in children with short stature.

Conclusions

Long-acting growth hormone replacement therapy had significantly lower height standard deviation scores chronological age, and insulin-like growth factor binding protein-3 compared to daily growth hormone in children with short stature. However, growth hormone replacement therapy had no significant difference in height velocity, height standard deviation scores bone age, insulin-like growth factor 1 standard deviation scores, and incidence of adverse events compared to daily growth hormone in children with short stature. Further studies are required to validate these findings.

Patient preferences for growth hormone treatment in Japanese children

BACKGROUND

There are not clear evidence to date evaluating patients' and caregivers' preferences for the recombinant-human growth hormone (r-hGH) injection in children in Japan. This study aimed to quantitatively evaluated the factors driving preferences for daily r-hGH injections among Japanese children with growth hormone deficiency (GHD) or their caregivers and to determine the relative importance of treatment delivery factors.

METHODS

This study was performed among Japanese children with GHD or their caregivers who visited a specialized clinic in Japan as part of their routine care. The participants were asked to complete a web-based discrete choice experiment (DCE) questionnaire.

RESULTS

Choice-based conjoint analysis was used to evaluate the relative importance of the attributes of the choice predictors and determine utility scores for each attribute. Of the 47 respondents who participated in this study, 41 were caregivers who responded on behalf of the patients, the remaining six were patients who completed the DCE themselves. The injection schedule was found to be the most important factor for both patients and caregivers; a once-weekly injection schedule was preferred over a daily injection schedule. Storage and preparation was deemed more important to patients than it was to caregivers, with patients preferring storage at room temperature even if it required additional mixing (reconstitution). Both patients and caregivers showed a clear preference for devices that offered a dose-setting memory.

CONCLUSIONS

A less frequent injection schedule may enhance adherence to r-hGH treatment and expected improve quality of life for GHD patients over the long term.

Twenty Years of GH Treatment in Adults with Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is a rare neurodevelopmental genetic disorder. In adults, the syndrome is characterised by muscular hypotonia, a different body composition with more body fat than muscle mass, hyperphagia, behavioural problems, and cognitive dysfunction. Endocrine deficiencies are common, including growth hormone (GH) deficiency. Here, we present data from a cross-sectional study in adults with PWS with a focus on the long-term safety of GH treatment. A total of 22 patients (14 men) were treated with GH for a median of 20 years. Data on body composition, hormones, and metabolic parameters were retrieved from the patients’ medical records. The median age was 27 years. The median GH dose was 0.5 mg/day. Insulin-like growth factor 1 (IGF-I) and blood lipids were normal, while fasting glucose and HbA1c were slightly elevated in three men with diabetes. Fat mass was less than fat free mass in all, though this was less pronounced in women. GH treatment did not negatively affect the metabolic profile, and none developed cardiovascular diseases or cancer. All adults on long-term GH treatment had a normal body composition and our results indicate that treatment was safe. However, PWS is a complex, multisystemic disease and continuous, individual considerations are required during GH treatment, especially in patients with risk factors for adverse effects.

Usefulness and Potential Pitfalls of Long-Acting Growth Hormone Analogs

Daily recombinant human GH (rhGH) is currently approved for use in children and adults with GH deficiency (GHD) in many countries with relatively few side-effects. Nevertheless, daily injections can be painful and distressing for some patients, often resulting in non-adherence and reduction of treatment outcomes. This has prompted the development of numerous long-acting GH (LAGH) analogs that allow for decreased injection frequency, ranging from weekly, bi-weekly to monthly. These LAGH analogs are attractive as they may theoretically offer increased patient acceptance, tolerability, and therapeutic flexibility. Conversely, there may also be pitfalls to these LAGH analogs, including an unphysiological GH profile and differing molecular structures that pose potential clinical issues in terms of dose initiation, therapeutic monitoring, incidence and duration of side-effects, and long-term safety. Furthermore, fluctuations of peak and trough serum GH and IGF-I levels and variations in therapeutic efficacy may depend on the technology used to prolong GH action. Previous studies of some LAGH analogs have demonstrated non-inferiority compared to daily rhGH in terms of increased growth velocity and improved body composition in children and adults with GHD, respectively, with no significant unanticipated adverse events. Currently, two LAGH analogs are marketed in Asia, one recently approved in the United States, another previously approved but not marketed in Europe, and several others proceeding through various stages of clinical development. Nevertheless, several practical questions still remain, including possible differences in dose initiation between naïve and switch-over patients, methodology of dose adjustment/s, timing of measuring serum IGF-I levels, safety, durability of efficacy and cost-effectiveness. Long-term surveillance of safety and efficacy of LAGH analogs are needed to answer these important questions.

In-vitro Release Evaluation of Growth Hormone from an Injectable In-Situ Forming Gel Using PCL-PEG-PCL Thermosensitive Triblock

OBJECTIVE

An injectable long acting In-Situ Forming Gel (ISFG) of human Growth Hormone (hGH) was prepared by using triblock PCL-PEG-PCL (Mw 1500-1500-1500). Ring-Opening Polymerization (ROP) of triblock using microwave was applied.

METHODS

The BCA protein assay Kit was used to determine the concentration of hGH in the in-vitro release medium. Finally, Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) tests and Circular Dichroism (CD) spectrum were done to approve the stability of released hGH. The result of ROP demonstrated that the proportion of PCL to PEG accorded with the initial molar ratio of the monomers. The cross-section of the Surface Electron Microscopy (SEM) indicated the porous framework of the hydrogel could load the drug into its tridimensional matrixes structure. There is the low initial burst release of hGH from the supramolecular hydrogel.

RESULTS

The maximum in-vitro release of hGH was 71.2 % ± 1.5 that were due to hGH degrading after this time (21 days). The CD spectrum and SDS-PAGE results confirmed the stability of hGH during invitro release evaluation.

CONCLUSION

The results suggest that the sustained-release formulation using PCL-PEG-PCL can be applied to control the release of hGH.

Safety of current recombinant human growth hormone treatments for adults with growth hormone deficiency and unmet needs

INTRODUCTION

Growth hormone (GH) deficiency (GHD) in adults is characterized by abnormal body composition, unfavorable cardiovascular risk factors, and poor quality of life. The diagnosis is made within appropriate clinical settings and according to established guidelines. Numerous studies have shown that GH treatment improves body composition, cardiovascular risk factors, physical capacity, and quality of life while issues on safety, in particular long-term safety, remain.

AREAS COVERED

Short- and long-term safety of GH replacement in adults with GHD.

EXPERT OPINION

Adults with GHD are an inhomogeneous group of patients and GH replacement requires individual considerations. Most adverse effects are mild and transient and related to fluid retention and GH dose. In patients without comorbidities long-term GH treatment is safe and development of diabetes, cardiovascular disease, or tumors are not increased. Furthermore, mortality is not increased. Patients with risk factors should be identified before GH treatment is initiated and an optimal balance between benefit and risk established. Studies with sufficient duration and power to identify the development of cardiovascular diseases and cancers are still awaited. Effective management of comorbidities can be expected to decrease morbidity and mortality and improve quality of life. Studies with long-acting GH formulations are ongoing and available data indicate similar effects and short-time safety.

Physician' attitudes to growth hormone replacement therapy in adults following pituitary surgery: Results of an online survey

OBJECTIVE

The aim of this study was to evaluate physician attitudes and practices in the management of adult growth hormone deficiency (GHD) following pituitary surgery.

MATERIALS AND METHODS

An online questionnaire survey was sent to a sample group of physicians.

RESULTS

A total of 131 respondents provided usable responses. More than three quarters were senior physicians, with most practicing in tertiary care centers (73%). Four-fifths of the respondents see at least 1 to 5 patients with GHD following pituitary surgery per year. Seventy-four percent acknowledge the benefit in principle of growth hormone replacement therapy (GHRT) for patients with GHD after pituitary surgery. Most respondents (84%) would only consider GHRT for symptomatic patients. However, 16% stated that patients with GHD after pituitary surgery generally suffer from the side effects of GHRT. Forty-four percent said that the serum insulin-like growth factor-1 (IGF-1) level is the best screening test for assessing GHD after pituitary surgery but 57% of the respondents would use IGF-I levels, and 29% the insulin tolerance test (ITT), in patients with a documented deficiency in three pituitary axes. The main barriers to long-term GHRT use were that it requires injections (67%), and is costly with limited supply (61%). Other reasons not to use GHRT include an absence of GHD symptoms and apparent GHT ineffectiveness (44%), physician lack of familiarity with the medication (40%), and lack of adherence to available guidelines (38%).

CONCLUSION

This survey addressed physician attitudes and practices in recognizing and treating GHD in adult's post-pituitary surgery. Regional guidelines must be developed to help address/tackle these issues and assist physicians in understanding and treating this condition.

Pharmacokinetics of Recombinant Human Growth Hormone (rhGH) in Beagles by ELISA

Background::

Somatropin is recombinant human growth (GH) used for the treatment of growth failure in children and GH deficiency in adults. At present, rhGH marketed in China is mostly freeze-dried powder injection. As the lyophilization process is unstable, time-consuming and costly, rhGH has been prepared into an aqueous solution for administering directly.

Introduction::

In this study, the pharmacokinetics of two dosage forms of rhGH in beagle dogs after single subcutaneous administration was determined by enzyme-linked immunosorbent assay (ELISA).

Methods:

Twelve healthy beagles (male, 6:female, 6) were used for the pharmacokinetic study and were equally divided into two groups. Subcutaneous injection of 0.2 IU/kg with rhGH in the two formulations. The blood samples were taken from forearms, 0, 0.033, 0.083, 0.25, 0.5, 1, 2, 3, 4, 7, 10, 24 h and collected the beagle plasma on time. The pharmacokinetic parameters of rhGH after subcutaneous (s.c.) injection were determined experimentally on beagles. Primary PK endpoints were area under the serum concentration-time curve (AUC0-t) and maximum serum concentration (Cmax). Serum rhGH level was determined by enzyme-linked immunosorbent assay.

Results::

The calibration curves obtained were linear over the concentration range of 25 to 1600 ng/ml for recombinant human growth. The results of the intra- and inter-day precision and accuracy studies were well within the acceptable limits. The analysis samples were stable under different storage conditions and temperature.

Conclusions::

The developed ELISA method has been successfully applied to the studies of pharmacokinetic of recombinant human growth hormone in beagles.

Long-Acting Growth Hormone Preparations - Current Status and Future Considerations

CONTEXT

Long-acting GH (LAGH) preparations are currently being developed in an attempt to improve adherence. The profile of GH action following administration of LAGH raises practical questions about clinical monitoring and long-term safety and efficacy of these new therapeutic agents.

METHODS

Recent literature and meeting proceedings regarding LAGH preparations are reviewed.

RESULTS

Multiple LAGH preparations are currently at various stages of development, allowing for decreased GH injection frequency from daily to weekly, biweekly, or monthly. Following administration of LAGH, the serum peak and trough GH and IGF-I levels vary depending upon the mechanism used to prolong GH action. Randomized, controlled clinical trials of some LAGH preparations have reported non-inferiority compared with daily recombinant human GH (rhGH) for improved growth velocity and body composition in children and adults with GH deficiency (GHD), respectively. No significant LAGH-related adverse events have been reported during short-term therapy.

CONCLUSION

Multiple LAGH preparations are proceeding through clinical development with some showing promising evidence of short-term clinical efficacy and safety in children and adults with GHD. The relationship of transient elevations of GH and IGF-I following administration of LAGH to efficacy and safety remain to be elucidated. For LAGH to replace daily rhGH in the treatment of individuals with GHD, a number of practical questions need to be addressed including methods of dose adjustment, timing of monitoring of IGF-I, safety, efficacy, and cost-effectiveness. Long-term surveillance of efficacy and safety of LAGH preparations will be needed to answer these clinically relevant questions.

Engineered small metal-binding protein tag improves the production of recombinant human growth hormone in the periplasm of Escherichia coli

Fusion proteins play an important role in the production of recombinant proteins in Escherichia coli. They are mostly used for cytoplasmic expression since they can be designed to increase the solubility of the target protein, which then can be easily purified via affinity chromatography. In contrast, fusion proteins are not usually included in construct designs for periplasmic production. Instead, a signal sequence is inserted for protein transport into the periplasm and a C-terminal his-tag added for subsequent purification. Our research group has proposed the small metal-binding protein (SmbP) isolated from the periplasm of Nitrosomonas europaea as a new fusion protein to express recombinant proteins in the cytoplasm or periplasm of E. coli. SmbP also allows purification via immobilized metal affinity chromatography using Ni(II) ions. Recently, we have optimized the periplasmic production of proteins tagged with SmbP by exchanging its native signal peptide with one taken from pectate lyase B (PelB), substantially increasing the amount of protein produced. In this work, we have expressed and purified soluble bioactive human growth hormone (hGH) tagged with PelB-SmbP and obtained the highest periplasmic production reported for this protein so far. Its activity, tested on Nb2-11 cells, was equivalent to commercial growth hormone at 50 ng·mL-1 . Therefore, we strongly recommend the use of PelB-SmbP as a protein tag for the expression and purification of hGH or other possible target proteins in the periplasm of E. coli.

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.

[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.

Adult growth hormone deficiency: clinical advances and approaches to improve adherence

Introduction: There have been significant clinical advances in the understanding of the diagnosis and benefits of long-term recombinant human growth hormone (rhGH) replacement in adults with GH deficiency (GHD) since its approval in 1996 by the United States Food and Drug Administration.Areas covered: We searched PubMed, Medline, CINAHL, EMBASE and PsychInfo databases between January 2000 and June 2019 for published studies evaluating adults with GHD. We reviewed the data of the oral macimorelin test compared to the GHRH plus arginine and the insulin tolerance tests that led to its approval by the United States FDA and European Medicines Agency for adult diagnostic testing. We summarize the clinical advances of long-term benefits of rhGH therapy and the potential effects of GH receptor polymorphisms on individual treatment responsiveness. We identify that non-adherence and discontinuation rates are high and recommend strategies to support patients to improve adherence. We also provide an overview of several long-acting GH (LAGH) preparations currently under development and their potential role in improving treatment adherence.Expert opinion: This article summarizes recent clinical advances in rhGH replacement therapy, the biological and molecular aspects that may influence rhGH action, and offers practical strategies to enhance adherence in adults with GHD.

Two years in growth hormone 2017-18

This brief review highlights new studies in three areas of the GH field, namely diagnostics, therapeutics and biomarkers. The diagnosis of GH deficiency has always presented a challenge: there is no "gold standard" test of GH status, and GH levels during stimulation testing are affected by many factors that limit diagnostic accuracy. Two new approaches to diagnosis have been proposed: one involves a classical endocrine test of GH production using a GH secretagogue to test the Ghrelin axis, and shows promise in the diagnosis of adult GH deficiency. The other uses a completely different approach analysing the individual's gene expression profile as a surrogate for GH status with high levels of test accuracy. From the therapeutic aspect, there have been significant efforts to produce a long-acting (LA) GH on the premise that this will improve adherence and patient convenience. Aspects of LA-GH pharmacology are considered, and it will be interesting to see in future years what place LA-GH GH takes in the market. Long term surveillance is a vital part of therapeutics; recent studies across Europe have provided reassurance on the safety of recombinant human GH (r-hGH) for those with uncomplicated growth disorders, but do emphasise the need to continue observation through adulthood. The search for biomarkers that precisely reflect GH action in children and adults is an ongoing task. One of the newer bone markers that shows promise is a fragment of collagen type X which now requires further investigation in humans. In parallel with the diagnostic studies, gene expression profiles at the start of r-hGH treatment have been used to predict GH response in children with GHD and girls with Turner syndrome. These data are promising but need evaluation across a range of growth disorders. R-hGH is an effective, safe therapy used in both children and adults. There is however a need to continue to refine diagnosis, treatment and most importantly long-term pharmacovigilance to ensure that the right patients have the best treatment with robust safety profiles.

Efficacy and safety of long-acting growth hormone in children with short stature: a systematic review and meta-analysis

PURPOSE

Long-acting growth hormone (GH) has been developed to address the noncompliance and decreased efficacy associated with daily GH injections. We aimed to evaluate the efficacy and safety of long-acting GH replacement therapy in children with short stature.

METHODS

Randomized controlled trials (RCTs) that investigated the efficacy and safety of long-acting GH therapy in children with short stature in comparison with daily GH injections were searched in Medline, Embase, and the Cochrane Central Register of Controlled Trials. A random-effect model was used to pool data using mean difference and odds ratios (OR). (PROSPERO registration number: CRD42018111105).

RESULTS

Seven relevant studies were finally included. Meta-analysis found there was no significant difference between high-dose long-acting GH and daily GH in terms of height velocity (HV) (mean difference (MD) = -0.10, 95% CI, -0.79 to 0.60, P = 0.79). Moreover, no significant difference was observed in height standard deviation scores (Ht SDS) between high-dose long-acting GH and daily GH (MD = -0.07, 95% CI, -0.18 to 0.03, P = 0.17). Treatment with high-dose long-acting GH significantly increased IGF-1 SDS when compared with daily GH (MD = 0.31, 95% CI, 0.06-0.56, P = 0.02). In safety assessment, no significant difference was observed in the incidence of adverse events between high-dose long-acting GH and daily GH (OR 1.42, 95% CI, 0.65-3.11, P = 0.38).

CONCLUSIONS

There is no evidence to support differences in the effects of long-acting GH compared with those of daily GH. More RCTs that focus on the safety of high-dose long-acting GH treatment, especially the detection of adverse events caused by elevated levels of serum IGF-1, are needed in the future.

Long-Acting Growth Hormone Preparations in the Treatment of Children

Human growth hormone (hGH), which had been in use since 1958, was supplanted by recombinant human growth hormone (rhGH) in 1985 for those with growth hormone deficiency (GHD). Adherence to daily subcutaneous growth hormone is challenging for patients. Thus, several companies have pursued the creation of long acting rhGH. These agents can be divided broadly into depot formulations, PEGylated formulations, pro-drug formulations, non-covalent albumin binding GH and GH fusion proteins. Nutropin Depot is the only long acting rhGH ever approved by the U.S. Food and Drug Administration, and it was removed from the market in 2004. Of the approximately seventeen candidate drugs, only a handful remain under active clinical investigation or are commercially available.

GH and IGF-1 Replacement in Children

In this chapter, we want to give an overview on what we have learned from more than 30 years ago on the use of recombinant human growth hormone (rhGH) and later recombinant human IGF-1 which was introduced for the treatment of short children and what are the safety issues concerned with this treatment. However, rhGH is used not solely in conditions where short stature is the consequence of GH deficiency but also in various disorders without a proven GH deficiency. In clinical studies, growth responses to various forms of rhGH therapy were analyzed, adding to our concept about the physiology of growth. Most patients under rhGH treatment show a considerable short-term effect; however, the long-term gain of height in a child obtained by a year-long treatment until final height remains controversial in some of the growth disorders that have been treated with rhGH or IGF-1. Today the first studies on the long-term safety of rhGH treatment have been published and raising some questions whether this treatment is similarly safe for all the patient groups treated with rhGH. Although there is a long-standing safety record for these hormone replacement therapies, in the face of the considerable costs involved, the discussion about the risk to benefit ratio is continuing. Newer developments of rhGH treatment include long-term preparations, which have only to be injected once a week. Although some of these drugs already have proven their non-inferiority to conventional rhGH treatment, we have to await further results to see whether they show improvements in treatment adherence of the patients and prove their long-term safety.

New Insights in Growth Hormone Stimulation Tests Protocols

Objective: The objective of this study was to analyze the performance of 2 stimulation tests used in the diagnosis of growth hormone deficiency.

Method: A retrospective study was conducted on a non-random sample of 310 patients, between 2 and 20 years old, who were hospitalized in the Mureș County Hospital’s Endocrinology Department and in the National Institute of Endocrinology C.I. Parhon with short stature between 2009-2015. Inclusion criteria: all subjects who underwent growth hormone stimulation tests in accordance with the national protocol. Microsoft Office Excel was used for data collection and MedCalc v 12.5 was used for statistical analysis.

Results: From the total of 310 patients, 102 were diagnosed in Târgu Mureș and 208 in Bucharest. Sex ratio favored boys (boys:girls 1.64:1). In 173 subjects growth hormone deficiency was confirmed. For both tests the percentage of maximum response was the highest for the 60 minutes blood sample regardless if the test were positive or not. Both tests have 100% sensitivity and negative predictive value, with the highest specificity for the 60 minutes clonidine and 30 minutes insulin. The false positive rate was 60% for the insulin test and 27.2% for clonidine for Târgu Mureș sample and 86.9% for the insulin test and 62.5% for clonidine for Bucharest sample. The concordance of the 2 tests was 49.36%.

Conclusions: Stimulating growth hormone testing has a number of limitations but is still needed in some auxological circumstances. We recommend performing the clonidine test first to exclude idiopathic short stature and then the insulin tolerance test for the diagnosis of growth hormone deficiency.

The current state of long-acting growth hormone preparations for growth hormone therapy

PURPOSE OF REVIEW

To discuss the rationale of developing long-acting growth hormone (LAGH) preparations, to describe the technologies designed to prolong GH action, and to address key issues regarding efficacy, safety, and monitoring while on treatment.

REVIEW FINDINGS

Recombinant human GH is currently approved for daily use and has been shown to restore longitudinal growth, and improve body composition with relatively few side-effects in children and adults with GH deficiency, respectively. However, daily injections can be inconvenient, painful and distressing for some patients, resulting in decreased adherence and efficacy. Over a dozen pharmaceutical companies have designed LAGH preparations that are at various stages of development using a number of different methods to prolong GH action.

SUMMARY

LAGH will represent an advancement over daily recombinant human GH injections because of fewer injections that may offer increased acceptance, tolerability, and therapeutic flexibility to patients that potentially can improve treatment outcomes. However, given the unphysiological profile of LAGH preparations, long-term surveillance of efficacy and safety are needed. This review summarizes recent developments of LAGH preparations, and highlights the importance of long-term surveillance registries to assess for efficacy and safety that will be essential for understanding the impact of prolonged exposure to these compounds.

Broad variability in pharmacokinetics of GH following rhGH injections in children

OBJECTIVE

Daily subcutaneous self-injection of GH is used worldwide to treat short stature in childhood; longitudinal data on the impact of this regimen on GH-uptake are lacking.

DESIGN

Children with/without GH-deficiency participating in clinical trials were followed prospectively (≤8 times). Blood was sampled pre-GH-injection (dose GH³³/GH⁶⁷ μg/kg) and either every 30 min thereafter for 24 h (Experimental-setting; 59 GH-curves/15 children); or every 2 h thereafter for 16 h (Clinical-setting; 429 GH-curves/117 children). Pharmacokinetics were estimated by time T_max (h) of maximal GH-concentration (C_max, mU/L) and area under the curve for 16 h (AUC, mU/L ∗ h).

RESULTS

In the Clinical-setting, median C_max was 71 mU/L and AUC was 534 mU/L ∗ h, with coefficients of variation for intra-individual variation of 39% and 36%, respectively, and inter-individual variation of 44% and 42%, respectively. 43% of C_max and AUC variability was explained by GH-dose and proxies for injection depth (baseline GH-level, GH_peakwidth, BMI_SDS). In the Experimental- versus Clinical-setting, 85% and 40% of GH-curves, respectively, reached zero-levels within 24 h. A longer duration was found following a more superficial GH-injection. Spontaneous GH-peaks were identified already 6 h after the GH-injection in about half of the curves of both GHD and non-GHD patients.

CONCLUSION

Very broad intra-individual and inter-individual variability was found. A high GH-peak will optimize growth effects; the highest C_max was found after a deep injection of GH at the higher dose and concentration. In as many as 60% of the children, GH remained detectable in serum after 24 h; a constant GH-level will promote IGF-I and metabolic effects.

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.

The growth hormone-insulin-like growth factor-I axis in the diagnosis and treatment of growth disorders

The growth hormone (GH)-insulin-like growth factor (IGF)-I axis is a key endocrine mechanism regulating linear growth in children. While paediatricians have a good knowledge of GH secretion and assessment, understanding and use of measurements of the components of the IGF system are less current in clinical practice. The physiological function of this axis is to increase the anabolic cellular processes of protein synthesis and mitosis, and reduction of apoptosis, with each being regulated in the appropriate target tissue. Measurement of serum IGF-I and IGF-binding protein (IGFBP)-3 concentrations can complement assessment of GH status in the investigation of short stature and contribute to prediction of growth response during GH therapy. IGF-I monitoring during GH therapy also informs the clinician about adherence and provides a safety reference to avoid over-dosing during long-term management.

Treatment with Growth Hormone for Adults with Growth Hormone Deficiency Syndrome: Benefits and Risks

Pharmacological treatment of growth hormone deficiency (GHD) in adults began in clinical practice more than 20 years ago. Since then, a great volume of experience has been accumulated on its effects on the symptoms and biochemical alterations that characterize this hormonal deficiency. The effects on body composition, muscle mass and strength, exercise capacity, glucose and lipid profile, bone metabolism, and quality of life have been fully demonstrated. The advance of knowledge has also taken place in the biological and molecular aspects of the action of this hormone in patients who have completed longitudinal growth. In recent years, several epidemiological studies have reported interesting information about the long-term effects of GH replacement therapy in regard to the possible induction of neoplasms and the potential development of diabetes. In addition, GH hormone receptor polymorphism could potentially influence GH therapy. Long-acting GH are under development to create a more convenient GH dosing profile, while retaining the excellent safety, efficacy, and tolerability of daily GH. In this article we compile the most recent data of GH replacement therapy in adults, as well as the molecular aspects that may condition a different sensitivity to this treatment.

Challenges and future for the delivery of growth hormone therapy

Growth hormone (GH) has multiple roles in sustaining human development and homeostasis. Its pulsatile secretion stimulates growth and contributes to an equilibrium in a process tightly regulated and coordinated by many organs. GH deficiency is a medical condition affecting all ages, with not only significant consequences in the health of the patient but also impact on the quality of life. This review gathers the different strategies used today with a glance at future technologies to treat GH deficiency. We present key aspects for consideration when developing new methods to deliver GH, mimicking or replacing its pulsatile activity. Today and in the future, the fusion of biochemistry, biology and nanotechnology will provide hybrid devices using microfluidic systems. But, until new technologies for GH delivery will become available, current methods must be reinforced in conjunction with the development of better communication strategies between the health system and patients. Treating GH deficiency represents a multidisciplinary effort for which this review provides a glance at potential future directions for this therapy.

Update on GH therapy in adults

Over the last three decades, short- and long-term observational studies, clinical trials, systematic reviews, and meta-analyses have provided relevant information on the efficacy and safety of growth hormone (GH) replacement therapy in adults with GH deficiency (AGHD). The knowledge acquired during this time has been compiled into different guidelines that offer clinicians an evidence-based, practical approach for the management of AGHD. There are, however, still open questions in some key areas in which recommendations are supported by only moderate or weak evidence. In the last recent years, the development of long-acting GH preparations has created new therapeutic possibilities by decreasing injection frequency, improving adherence and thereby potentially maximizing clinical outcomes. The aims of this review are to advance our understanding on the diagnosis and treatment of AGHD and to present an update and future perspectives on the use of long-acting GH preparations.

Pharmacokinetics, Pharmacodynamics, and Safety of a Long-Acting Human Growth Hormone (MOD-4023) in Healthy Japanese and Caucasian Adults

Daily injections of growth hormone (GH) as replacement therapy in GH-deficient (GHD) patients may cause poor compliance and inconvenience. C-terminal peptide-modified human GH (MOD-4023) has been developed for once-weekly administration in GHD adults and children. In the present study, the pharmacokinetics (PK) and pharmacodynamics (PD) of a single subcutaneous dose of MOD-4023 were evaluated in healthy Caucasian and Japanese adults, using a phase 1 double-blind, vehicle-controlled, randomized study design. The study was conducted in 42 healthy Japanese (n = 21) and Caucasian (n = 21) men receiving either MOD-4023 at a dose of 2.5, 7.5, or 15 mg or vehicle. In the 2.5- and 7.5-mg cohorts, no differences in mean MOD-4023 serum concentration were found between Japanese and Caucasian subjects. A comparison of PK parameters in the 15-mg group suggests a slower absorption rate of MOD-4023 in Japanese subjects. PD analysis showed no apparent differences in IGF-1 and IGFBP-3 plasma concentrations between the Japanese and Caucasian subjects and indicated that a dose of 15 mg achieved the maximal effect in both ethnic groups. MOD-4023 demonstrated a favorable safety profile and local tolerance following single-dose subcutaneous administration. This study provides additional support for the development of MOD-4023 as a long-acting human growth hormone formulation for once-weekly administration.

The rationale and design of TransCon Growth Hormone for the treatment of growth hormone deficiency

The fundamental challenge of developing a long-acting growth hormone (LAGH) is to create a more convenient growth hormone (GH) dosing profile while retaining the excellent safety, efficacy and tolerability of daily GH. With GH receptors on virtually all cells, replacement therapy should achieve the same tissue distribution and effects of daily (and endogenous) GH while maintaining levels of GH and resulting IGF-1 within the physiologic range. To date, only two LAGHs have gained the approval of either the Food and Drug Administration (FDA) or the European Medicines Agency (EMA); both released unmodified GH, thus presumably replicating distribution and pharmacological actions of daily GH. Other technologies have been applied to create LAGHs, including modifying GH (for example, protein enlargement or albumin binding) such that the resulting analogues possess a longer half-life. Based on these approaches, nearly 20 LAGHs have reached various stages of clinical development. Although most have failed, lessons learned have guided the development of a novel LAGH. TransCon GH is a LAGH prodrug in which GH is transiently bound to an inert methoxy polyethylene glycol (mPEG) carrier. It was designed to achieve the same safety, efficacy and tolerability as daily GH but with more convenient weekly dosing. In phase 2 trials of children and adults with growth hormone deficiency (GHD), similar safety, efficacy and tolerability to daily GH was shown as well as GH and IGF-1 levels within the physiologic range. These promising results support further development of TransCon GH.

Nonclinical pharmacokinetic and pharmacodynamic characterisation of somapacitan: A reversible non-covalent albumin-binding growth hormone

OBJECTIVE

Somapacitan is an albumin-binding growth hormone derivative intended for once weekly administration, currently in clinical development for treatment of adult as well as juvenile GH deficiency. Nonclinical in vivo pharmacological characterisation of somapacitan was performed to support the clinical trials. Here we present the pharmacokinetic and pharmacodynamic effects of somapacitan in rats, minipigs, and cynomolgus monkeys.

METHODS

Pharmacokinetic studies investigating exposure, absorption, clearance, and bioavailability after single intravenous (i.v.) and subcutaneous (s.c.) administration were performed in all species. A dose-response study with five dose levels and a multiple dose pharmacodynamic study with four once weekly doses was performed in hypophysectomised rats to evaluate the effect of somapacitan on growth and IGF-I production.

RESULTS

Pharmacokinetic profiles indicated first order absorption from the subcutaneous tissue after s.c. injections for somapacitan in all three species. Apparent terminal half-lives were 5-6h in rats, 10-12h in minipigs, and 17-20h in monkeys. Somapacitan induced a dose-dependent growth in hypophysectomised rats (p<0.001) and an increase in plasma IGF-I levels in rats (p<0.01), minipigs (p<0.01), and cynomolgus monkeys (p<0.05) after single dose administration. Multiple once weekly dosing of somapacitan in hypophysectomised rats induced a step-wise increase in body weight with an initial linear phase the first 3-4days in each dosing interval (p<0.001).

CONCLUSION

The nonclinical pharmacokinetic and pharmacodynamic studies of somapacitan showed similar pharmacokinetic properties, with no absorption-limited elimination, increased clearance and increased and sustained levels of IGF-I in plasma for up to 10days after a single dose administration in all three species. Somapacitan induced a dose-dependent increase in body weight and IGF-I levels in hypophysectomised rats. Multiple dosing of somapacitan in hypophysectomised rats suggested a linear growth for the first 3-4days in each weekly dosing interval, whereas daily hGH dosing showed linear growth for approximately two weeks before reaching a plateau level.

Long-acting PEGylated recombinant human growth hormone (Jintrolong) for children with growth hormone deficiency: phase II and phase III multicenter, randomized studies

OBJECTIVE

We assessed the efficacy and safety of a weekly pegylated human growth hormone (PEG-rhGH) (Jintrolong) vs daily rhGH for children with growth hormone deficiency (GHD).

DESIGN

Phase II and III, multicenter, open-label, randomized controlled trials.

METHODS

108 and 343 children with treatment-naive GHD from 6 hospitals in China were enrolled in the phase II and III studies respectively. Patients in the phase II study were randomized 1:1:1 to weekly Jintrolong (0.1 mg/kg/week PEG-rhGH complex), weekly Jintrolong (0.2 mg/kg/week PEG-rhGH complex) or daily rhGH (0.25 mg/kg/week) for 25 weeks. Patients in the phase III study were randomized in a 2:1 ratio to weekly Jintrolong (0.2 mg/kg/week) or daily rhGH (0.25 mg/kg/week) for 25 weeks. The primary endpoint for both studies was height velocity (HV) increase at the end of treatment. Other growth-related parameters, safety and compliance were also monitored.

RESULTS

The phase II study established the preliminary efficacy, safety and recommended dose of Jintrolong PEG-rhGH. In the phase III study, we demonstrated significantly greater HV increases in patients receiving Jintrolong treatment (from 2.26 ± 0.87 cm/year to 13.41 ± 3.72 cm/year) vs daily rhGH (from 2.25 ± 0.82 cm/year to 12.55 ± 2.99 cm/year) at the end of treatment (P < 0.05). Additionally, significantly greater improvement in the height standard deviation scores was associated with Jintrolong throughout the treatment (P < 0.05). Adverse event rates and treatment compliance were comparable between the two groups.

CONCLUSION

Jintrolong PEG-rhGH at a dose of 0.2 mg/kg/week for 25 weeks is effective and safe for GHD treatment and is non-inferior to daily rhGH.

Long-Acting C-Terminal Peptide-Modified hGH (MOD-4023): Results of a Safety and Dose-Finding Study in GHD Children

CONTEXT

Daily injections are required for growth hormone (GH) replacement therapy, which may cause low compliance as a result of inconvenience and distress in patients.

OBJECTIVE

C-terminal peptide-modified human GH (MOD-4023) is developed for once-a-week dosing regimen in GH-deficient (GHD) adults and children. The present trial was a safety and dose-finding study for weekly MOD-4023 in GHD children.

DESIGN

A multicenter, open-label, randomized, controlled phase 2 study in children with GHD, evaluating the safety, tolerability, pharmacokinetics/pharmacodynamics, and efficacy of three different weekly MOD-4023 doses, compared with daily recombinant human GH (r-hGH).

SETTING

The trial was conducted in 14 endocrinology centers in Europe.

PATIENTS

Fifty-three prepubertal children with GHD completed 12 months of treatment with either MOD-4023 (N = 42) or r-hGH (N = 11).

INTERVENTIONS

C-terminal peptide-modified hGH (MOD-4023) was administered weekly at a dose of either 0.25, 0.48, or 0.66 mg/kg/wk and compared with daily hGH at a dose of 0.24 mg/kg/wk.

RESULTS

MOD-4023 showed an estimated half-life approximately fivefold to 10-fold longer when compared with daily r-hGH. Insulin-like growth factor (IGF)-I and IGF-binding peptide 3 showed a dose-dependent increase during MOD-4023 treatment. IGF-I standard deviation score for MOD-4023 did not exceed +2. All MOD-4023 cohorts demonstrated adequate catch-up growth. The 0.66 mg/kg/wk dose demonstrated efficacy closest to daily r-hGH. No serious adverse events were observed during MOD-4023 treatment, and its tolerability was consistent with known properties of r-hGH.

CONCLUSIONS

This study confirms the long-acting properties of MOD-4023 and shows a promising safety and tolerability profile. This provides support for initiation of a phase 3 study in GHD children using a single weekly injection of MOD-4023.

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.

Optimizing Patient Management and Adherence for Children Receiving Growth Hormone

Poor adherence with growth hormone (GH) therapy has been associated with worse clinical outcomes, which in children relates specifically to their linear growth and loss of quality of life. The "360° GH in Europe" meeting, held in Lisbon, Portugal, in June 2016 and funded by Merck KGaA (Germany), examined many aspects of GH diseases. The three sessions, entitled "Short Stature Diagnosis and Referral," "Optimizing Patient Management," and "Managing Transition," each benefited from three guest speaker presentations, followed by an open discussion and are reported as a manuscript, authored by the speakers. Reported here is a summary of the proceedings of the second session, which reviewed the determinants of GH therapy response, factors affecting GH therapy adherence and the development of innovative technologies to improve GH treatment in children. Response to GH therapy varies widely, particularly in regard to the underlying diagnosis, although there is little consensus on the definition of a poor response. If the growth response is seen to be less than expected, the possible reasons should be discussed with patients and their parents, including compliance with the therapy regimen. Understanding and addressing the multiple factors that influence adherence, in order to optimize GH therapy, requires a multi-disciplinary approach. Because therapy continues over many years, various healthcare professionals will be involved at different periods of the patient's journey. The role of the injection device for GH therapy, frequent monitoring of response, and patient support are all important for maintaining adherence. New injection devices are incorporating electronic technologies for automated monitoring and recording of clinically relevant information on injections. Study results are indicating that such devices can at least maintain GH adherence; however, acceptance of novel devices needs to be assessed and there remains an on-going need for innovations.

Injectable formulations of poly(lactic acid) and its copolymers in clinical use

Poly(lactic acid) and its copolymers have revolutionized the field of drug delivery due to their excellent biocompatibility and tunable physico-chemical properties. These copolymers have served the healthcare sector by contributing many products to combat various diseases and for biomedical applications. This article provides a comprehensive overview of clinically used products of poly(lactic acid) and its copolymers. Multi-dimension information covering product approval, formulation aspects and clinical status is described to provide a panoramic overview of each product. Moreover, leading patented technologies and various clinical trials on these products for different applications are included. This review focuses on marketed injectable formulations of PLA and its copolymers.

Availability and quality of illegitimate somatropin products obtained from the Internet

Background Growth hormones are widely available on the Internet for those who want to enhance their physical performance and improve body satisfaction. Illegitimate websites market somatropin injections without medical prescription and encourage misuse. Customers potentially put their health at risk when purchasing parenteral medications online. Objective The objective of our study was to evaluate the online market of no-prescription somatropin products and to analyse and document Internet pharmacy characteristics, distribution and pharmaceutical quality. Setting Websites indexed in Google promoting somatropin for sale direct to patients. Method Websites promoting the sale of growth hormone products were identified and analysed from June to August 2014. Internet vendor sites were evaluated to identify possible patient and medication safety concerns. Website characteristics, delivery time, storage conditions, packaging and attached product information were assessed. Investigation of the somatropin content was achieved using capillary electrophoresis with UV detection and electrospray ionization mass spectrometry. Main outcome measure Accessibility and quality of somatropin injections. Results Seventeen individual Internet vendor websites distributed somatropin products directly to patients, majority (94%) did not require a valid medical prescription before dispensing the products. Majority (70%) of Internet pharmacies displayed no medical information and none (0%) of the vendors displayed any regulatory body logo. All online samples had significantly (p < 0.001) lower somatropin concentration than labelled. Conclusion Our results clearly illustrate that prescription only biologic drugs are widely available online and can be easily accessed by anyone. Unprofessional distribution and handling is likely to cause degradation and possible patient safety concerns.

A long-acting GH receptor antagonist through fusion to GH binding protein

Acromegaly is a human disease of growth hormone (GH) excess with considerable morbidity and increased mortality. Somatostatin analogues are first line medical treatment but the disease remains uncontrolled in up to 40% of patients. GH receptor (GHR) antagonist therapy is more effective but requires frequent high-dose injections. We have developed an alternative technology for generating a long acting potent GHR antagonist through translational fusion of a mutated GH linked to GH binding protein and tested three candidate molecules. All molecules had the amino acid change (G120R), creating a competitive GHR antagonist and we tested the hypothesis that an amino acid change in the GH binding domain (W104A) would increase biological activity. All were antagonists in bioassays. In rats all antagonists had terminal half-lives >20 hours. After subcutaneous administration in rabbits one variant displayed a terminal half-life of 40.5 hours. A single subcutaneous injection of the same variant in rabbits resulted in a 14% fall in IGF-I over 7 days.

IN CONCLUSION

we provide proof of concept that a fusion of GHR antagonist to its binding protein generates a long acting GHR antagonist and we confirmed that introducing the W104A amino acid change in the GH binding domain enhances antagonist activity.

Safety and PK/PD correlation of TV-1106, a recombinant fused human albumin-growth hormone, following repeat dose administration to monkeys

PURPOSE

TV-1106 is a recombinant human albumin genetically fused to growth hormone which is intended to reduce the frequency of injections for GH therapy users. We report the safety, tolerability, pharmacokinetics and pharmacodynamics of repeated subcutaneous injections of TV-1106 in Cynomolgus monkeys.

METHOD

Cynomolgus monkeys received four weekly subcutaneous injections of 0, 5, 10 or 20mg/kg TV-1106 and were monitored for safety signals throughout the study. Serum levels of TV-1106 and insulin-like growth factor 1 (IGF-1) were assayed.

RESULTS

Treated animals showed no adverse effects or histopathological changes. TV-1106 serum concentrations showed sustained exposure to the drug. Exposure increased in a dose-dependent manner with peak concentrations at approximately 24h post-dosing and elimination half-lives in the range of 12 to 24h. IGF-1 serum concentrations were elevated throughout the entire study duration, indicative of the pharmacological response. There was a clear correlation between change in IGF-1 levels and dose or exposure to TV-1106.

CONCLUSIONS

The safety, pharmacokinetic and pharmacodynamic findings support the further development of TV-1106 as a once-weekly administered treatment for patients with GHD.

Assessment of the Pharmacokinetics, Pharmacodynamics, and Safety of Single Doses of TV-1106, a Long-Acting Growth Hormone, in Healthy Japanese and Caucasian Subjects

TV‐1106 is a human serum albumin genetically fused to recombinant human growth hormone, designed to provide a long‐acting alternative to daily growth hormone (GH) injections in patients with GH deficiency. This study investigated the pharmacokinetics, pharmacodynamics, and safety of single subcutaneous doses of TV‐1106 (7.5, 15, 50, and 100 mg) in Japanese (n = 44) and caucasian (n = 44) healthy subjects. TV‐1106 pharmacokinetics and pharmacodynamics were comparable in Japanese and caucasian populations. TV‐1106 demonstrated relatively slow absorption (median t_max, 10–30 hours) and a mean elimination half‐life of 26–36 hours. Apparent clearance and volume of distribution decreased with increasing TV‐1106 doses in both populations and appeared to increase more than dose proportionality across the tested doses. Insulin‐like growth factor‐1 (IGF‐1) and IGF binding protein‐3 (IGFBP‐3) increased in a dose‐related manner, with maximum responses observed at 33–96 and 42–109 hours, respectively. IGF‐1 and IGFBP‐3 returned to baseline values at 168 hours following 7.5 and 15 mg of TV‐1106, and 336 hours following 50 and 100 mg of TV‐1106. TV‐1106 appeared safe in both populations. There was no evidence of differences in pharmacokinetics, pharmacodynamics, or safety of TV‐1106 between Japanese and caucasian populations. The data also demonstrate long‐acting growth hormone properties of TV‐1106 and support its potential for once‐weekly dosing.

Growth Hormone Research Society perspective on the development of long-acting growth hormone preparations

OBJECTIVE

The Growth Hormone (GH) Research Society (GRS) convened a workshop to address important issues regarding trial design, efficacy, and safety of long-acting growth hormone preparations (LAGH).

PARTICIPANTS

A closed meeting of 55 international scientists with expertise in GH, including pediatric and adult endocrinologists, basic scientists, regulatory scientists, and participants from the pharmaceutical industry.

EVIDENCE

Current literature was reviewed for gaps in knowledge. Expert opinion was used to suggest studies required to address potential safety and efficacy issues.

CONSENSUS PROCESS

Following plenary presentations summarizing the literature, breakout groups discussed questions framed by the planning committee. Attendees reconvened after each breakout session to share group reports. A writing team compiled the breakout session reports into a draft document that was discussed and revised in an open forum on the concluding day. This was edited further and then circulated to attendees from academic institutions for review after the meeting. Participants from pharmaceutical companies did not participate in the planning, writing, or in the discussions and text revision on the final day of the workshop. Scientists from industry and regulatory agencies reviewed the manuscript to identify any factual errors.

CONCLUSIONS

LAGH compounds may represent an advance over daily GH injections because of increased convenience and differing phamacodynamic properties, providing the potential for improved adherence and outcomes. Better methods to assess adherence must be developed and validated. Long-term surveillance registries that include assessment of efficacy, cost-benefit, disease burden, quality of life, and safety are essential for understanding the impact of sustained exposure to LAGH preparations.

Considering GH replacement for GH-deficient adults with a previous history of cancer: a conundrum for the clinician

Previous studies have shown that GH and IGF-I may enhance tumorigenesis, metastasis, and cell proliferation in humans and animals. Evidence supporting this notion is derived from animal model studies, epidemiological studies, experience from patients with acromegaly, molecular therapeutic manipulation of GH and IGF-I actions, and individuals with GH receptor and congenital IGF-I deficiencies. Prior exposure to radiation therapy, aging, family history of cancer, and individual susceptibility may also contribute to increase this risk. Therefore, the use of GH replacement in patients with a history of cancer raises hypothetical safety concerns for patients, caregivers, and providers. Studies of GH therapy in GH-deficient adults with hypopituitarism and childhood cancer survivors have not convincingly demonstrated an increased cancer risk. Conversely, the risk of occurrence of a second neoplasm (SN) in childhood cancer survivors may be increased, with meningiomas being the most common tumor; however, this risk appears to decline over time. In light of these findings, if GH replacement is to be considered in patients with a previous history of cancer, we propose this consideration to be based on each individual circumstance and that such therapy should only be initiated at least 2 years after cancer remission is achieved with the understanding that in some patients (particularly those with childhood cancers), GH may potentially increase the risk of SNs. In addition, close surveillance should be undertaken working closely with the patient's oncologist. More long-term data are thus needed to determine if GH replacement in GH-deficient adults with a history of cancer is associated with the development of de novo tumors and tumor recurrence.

The kidneys play a central role in the clearance of rhGH in rats

The kidneys are thought to play an important role in the clearance of recombinant human growth hormone (rhGH), but the relative importance is not clear. Obtaining knowledge of clearance pathway is an important prerequisite for the development of new long acting growth hormone analogues targeted at treatment of patients with growth hormone disorders. The purpose of this study was to investigate the relative importance of the kidneys in the clearance of rhGH. The study employed a newly validated nephrectomy rat model and a population based pharmacokinetic approach to assess renal clearance of rhGH in non-anesthetized rats, anesthetized rats and in nephrectomized anesthetized rats. Clearance in non-anesthetized rats was 290 ml/h/kg. This was reduced to 185 ml/h/kg by anesthesia and further reduced to 18 ml/h/kg by nephrectomy. As nephrectomy was able to reduce clearance with 90%, we conclude that renal clearance plays a pivotal role in the elimination of rhGH in rats.

In Vitro and in Vivo Characterization of MOD-4023, a Long-Acting Carboxy-Terminal Peptide (CTP)-Modified Human Growth Hormone

MOD-4023 is a novel long-acting version of human growth hormone (hGH), containing the carboxy-terminal peptide (CTP) of human chorionic gonadotropin (hCG). MOD-4023 is being developed as a treatment for adults and children with growth hormone deficiency (GHD), which would require fewer injections than currently available GH formulations and thus reduce patient discomfort and increase compliance. This study characterizes MOD-4023's binding affinities for the growth hormone receptor, as well as the pharmacokinetic and pharmacodynamics, toxicology, and safety profiles of repeated dosing of MOD-4023 in Sprague-Dawley rats and Rhesus monkeys. Although MOD-4023 exhibited reduced in vitro potency and lower affinity to the GH receptor than recombinant hGH (rhGH), administration of MOD-4023 every 5 days in rats and monkeys resulted in exposure comparable to daily rhGH, and the serum half-life of MOD-4023 was significantly longer. Repeated administration of MOD-4023 led to elevated levels of insulin-like growth factor 1 (IGF-1), and twice-weekly injections of MOD-4023 resulted in larger increase in weight gain with fewer injections and a lower accumulative hGH dose. Thus, the increased half-life of MOD-4023 in comparison to hGH may increase the frequency of protein-receptor interactions and compensate for its decreased in vitro potency. MOD-4023 was found to be well-tolerated in rats and monkeys, with minimal adverse events, suggesting an acceptable safety profile. These results provide a basis for the continued clinical development of MOD-4023 as a novel treatment of GHD in children and adults.