IGF-1 and growth response to adult height in a randomized GH treatment trial in short non-GH-deficient children

Efficacy, safety, and patient satisfaction of norditropin and sogroya in patients with growth hormone deficiency: a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Growth hormone deficiency occurs when the pituitary gland does not produce enough growth hormone. Norditropin®, a recombinant human growth hormone, and Sogroya®, an albumin-binding growth hormone derivative, are prescribed for patients with growth hormone deficiency. This systematic review assesses the efficacy, safety, and patient satisfaction associated with Norditropin and Sogroya.

METHODS

We systematically searched PubMed, Web of Science, and Scopus databases to identify eligible comparative studies. All studies published until June 2023 were included in our analysis. Our outcomes for children included height velocity and height velocity standard deviation score. In contrast, adult outcomes included adverse events, insulin-like growth factor 1-standard deviation score (IGF-1 SDS), and the Treatment Satisfaction Questionnaire for Medication-9 (TSQM-9). Results are reported as odds ratio (OR) and mean difference (MD) with a 95% confidence interval (95% CI).

RESULTS

Ten studies involving 1058 participants (665 children and 393 adults) were included in the meta-analysis. In children, Norditropin at doses of 0.034 and 0.067 mg/kg/day was compared to Sogroya at doses of 0.04, 0.08, 0.16, and 0.24 mg/kg/week. The results showed that 0.034 mg/kg/day Norditropin had a favorable impact on height velocity (MD -2.01, 95% CI -3.7 to -2.12, p < 0.00001) and height velocity standard deviation score (Mean Difference -3.61, 95% CI -5.06 to -2.16, p < 0.00001) when compared to Sogroya 0.04 mg/kg/day. Other doses showed comparable results. In adults, the only significant side effect noted was rash, which favored Sogroya (OR 0.1, 95% CI 0.04-0.27, p < 0.00001). Additionally, IGF-1 SDS was significantly higher in the Sogroya group than in the Norditropin group (MD 0.25, 95% CI 0.02-0.48, p = 0.03). Furthermore, the overall score of the TSQM-9 questionnaire, which includes three domains: convenience, effectiveness, and satisfaction, was significantly higher in the Sogroya group compared to the Norditropin group (OR 6.36, 95% CI 3.92-8.8, p < 0.00001).

CONCLUSION

Norditropin and Sogroya showed comparable efficacy and safety profiles, except for the prevalence of rash in the Norditropin group, and Sogroya has higher satisfaction among adults. More high-quality studies with more patients are required to confirm these results.

Children With Idiopathic Short Stature: An Expanding Role for Genetic Investigation in Their Medical Evaluation

Short stature in children is a common reason for referral to a pediatric endocrinologist. Many genetic, nutritional, psychological, illness-related, and hormonal causes must be excluded before labeling as idiopathic. Idiopathic short stature is not a diagnosis, but rather describes a large, heterogeneous group of children, who are short and often slowly growing. As new testing paradigms become available, the pool of patients labeled as idiopathic will shrink, although most will have a polygenic cause. Given that many of the new diagnoses are involved in growth plate biology, physical examination should assess for subtle dysmorphology or disproportion of the skeleton that may indicate a heterozygous mutation that in its homozygous state would be apparent. When laboratory evaluations are negative, one may consider genetic testing, such as targeted gene or gene panel, comparative genomic hybridization, or whole exome or whole genome sequencing (respectively). With a known genetic diagnosis, targeted therapy may be possible rather than recombinant human growth hormone, where response is generally poorer than that for children with growth hormone deficiency, because the variety of diagnoses may have varying growth hormone sensitivity. A firm diagnosis has heuristic value: to truncate further diagnostic evaluation, alert the clinician to other possible comorbidities, inform the family for genetic counseling, and direct appropriate targeted therapy, if available.

Evaluation of Adult Height in Patients with Non-Permanent Idiopathic GH Deficiency

Background: Several studies have evaluated the role of IGF-1 in the diagnosis of growth hormone deficiency (GHD). According to a recent study, an IGF-1 concentration of a −1.5 standard deviation score (SDS) appeared to be the best cut-off for distinguishing between children with GHD and normal children. This value should always be interpreted in conjunction with other clinical and biochemical parameters for the diagnosis of GHD, since both stimulation tests and IGF-1 assays have poor diagnostic accuracy by themselves. Our study was designed to evaluate the adult height (AH) in children with short stature and baseline IGF-1 concentration ≤ −1.5 SDS. Design: This retrospective analysis included 52 children and adolescents evaluated over the last 30 years for short stature and/or deceleration of the growth rate who underwent diagnostic procedures to evaluate a possible GHD. Only the patients who had baseline IGF-1 values ≤−1.5 SDS at the time of the first test were included in the study. Patients with genetic/organic GHD or underlying diseases were not included. Method: The case group consisted of 24 patients (13 boys and 11 girls) with non-permanent, idiopathic, and isolated GHD (peak GH < 10 μg/L after two provocative tests with arginine (Arg), insulin tolerance test (ITT), and clonidine (Clo), or <20 μg/L after GHRH + Arginine (GHRH+Arg); normal MRI; normal GH; and/or normal IGF-1 concentrations at near-AH). These patients were treated with GH (25–35 μg/kg/die) until near-AH. The control group consisted of 28 patients (23 boys and 5 girls) with idiopathic short stature (ISS, normal peak GH after provocative testing, no evidence of other causes for their shortness). Both groups had basal IGF-1 ≤−1.5 SDS. Results: AH and height gain in both groups were comparable. In the group of cases, mean IGF-1 SDS at the time of diagnosis was significantly lower than the levels found at the time of retesting. Conclusions: In this study, both treated patients with idiopathic GHD and untreated patients with ISS reached similar near-AHs (within target height) and showed similar increases in SDS for their height. Thus, the efficacy of treatment with rhGH in these patients may be questionable. This could be due to the fact that children with ISS are frequently misdiagnosed with GHD.

Effects of Taekwondo Training on Growth Factors in Normal Korean Children and Adolescents: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The growth of children and adolescents is both an important health indicator and a major public health issue. Many recent studies have investigated the effects of taekwondo on growth factors, but no consensus has yet been reached. This meta-analysis aimed to determine the effects of taekwondo on the growth factors in children and adolescents (aged 8 to 16 years). Randomized controlled trials from PubMed, Web of Science, Cochrane Library, the Research Information Sharing Service, the Korea Citation Index, and the Korean-studies Information Service System were analyzed. The effect sizes (standardized mean differences, SMD) were calculated, the risk of bias and publication bias were assessed, and the effect size and subgroup analyses were pooled. We found that the taekwondo group had significantly higher levels of growth hormones (SMD 1.78, 95% confidence interval [CI] 0.98-2.58, and p < 0.001) and insulin-like growth factors (SMD 1.76, 95% CI 0.60-2.92, and p < 0.001) than the control group. For height, a medium effect size was observed (SMD 0.62, 95% CI -0.56-1.80, and p = 0.300), but the between-group difference was not significant. Thus, taekwondo had significant positive effects on the secretion of growth hormones and insulin-like growth factors in Korean children and adolescents. A longitudinal follow-up is necessary to determine the effect on height. This suggests that taekwondo can be recommended as an appropriate physical exercise for maintaining normal growth in children and adolescents.

Growth Responses During 3 Years of Growth Hormone Treatment in Children and Adolescents With Growth Hormone Deficiency: Comparison Between Idiopathic, Organic and Isolated Growth Hormone Deficiency, and Multiple Pituitary Hormone Deficiency

BACKGROUND

The study aimed to compare the growth responses to 3 years of growth hormone (GH) treatment in children and adolescents with GH deficiency (GHD) according to idiopathic, organic, isolated (IGHD), and multiple pituitary hormone deficiency (MPHD).

METHODS

Total 163 patients aged 2-18 years (100 males and 63 females; 131 idiopathic and 32 organic GHD; 129 IGHD and 34 MPHD) were included from data obtained from the LG Growth Study. Parameters of growth responses and biochemical results were compared during the 3-year GH treatment.

RESULTS

The baseline age, bone age (BA), height (Ht) standard deviation score (SDS), weight SDS, mid-parental Ht SDS, predicted adult Ht (PAH) SDS, and insulin like growth factor-1 (IGF-1) SDS were significantly higher in the organic GHD patients than in the idiopathic GHD patients, but peak GH on the GH-stimulation test, baseline GH dose, and mean 3-year-GH dosage were higher in the idiopathic GHD patients than in the organic GHD patients. The prevalence of MPHD was higher in the organic GHD patients than in the idiopathic GHD patients. Idiopathic MPHD subgroup showed the largest increase for the ΔHt SDS and ΔPAH SDS during GH treatment, and organic MPHD subgroup had the smallest mean increase after GH treatment, depending on ΔIGF-1 SDS and ΔIGF binding protein-3 (IGFBP-3) SDS. The growth velocity and the parental-adjusted Ht gain were greater in the idiopathic GHD patients than the organic GHD patients during the 3-year GH treatment, which may have been related to the different GH dose, ΔIGF-1 SDS, and ΔIGFBP-3 SDS between two groups. Multiple linear regression analysis revealed that baseline IGF-1 SDS, BA, and MPH SDS in idiopathic group and baseline HT SDS in organic group are the most predictable parameters for favorable 3-year-GH treatment.

CONCLUSION

The 3-year-GH treatment was effective in both idiopathic and organic GHD patients regardless of the presence of MPHD or underlying causes, but their growth outcomes were not constant with each other. Close monitoring along with appropriate dosage of GH and annual growth responses, not specific at baseline, are more important in children and adolescents with GHD for long-term treatment.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01604395.

Differential Diagnosis of the Short IGF-I-Deficient Child with Apparently Normal Growth Hormone Secretion

The current differential diagnosis for a short child with low insulin-like growth factor I (IGF-I) and a normal growth hormone (GH) peak in a GH stimulation test (GHST), after exclusion of acquired causes, includes the following disorders: (1) a decreased spontaneous GH secretion in contrast to a normal stimulated GH peak ("GH neurosecretory dysfunction," GHND) and (2) genetic conditions with a normal GH sensitivity (e.g., pathogenic variants of GH1 or GHSR) and (3) GH insensitivity (GHI). We present a critical appraisal of the concept of GHND and the role of 12- or 24-h GH profiles in the selection of children for GH treatment. The mean 24-h GH concentration in healthy children overlaps with that in those with GH deficiency, indicating that the previously proposed cutoff limit (3.0-3.2 μg/L) is too high. The main advantage of performing a GH profile is that it prevents about 20% of false-positive test results of the GHST, while it also detects a low spontaneous GH secretion in children who would be considered GH sufficient based on a stimulation test. However, due to a considerable burden for patients and the health budget, GH profiles are only used in few centres. Regarding genetic causes, there is good evidence of the existence of Kowarski syndrome (due to GH1 variants) but less on the role of GHSR variants. Several genetic causes of (partial) GHI are known (GHR, STAT5B, STAT3, IGF1, IGFALS defects, and Noonan and 3M syndromes), some responding positively to GH therapy. In the final section, we speculate on hypothetical causes.

GH Responsiveness in Children With Noonan Syndrome Compared to Turner Syndrome

BACKGROUND

Despite different genetic background, Noonan syndrome (NS) shares similar phenotype features to Turner syndrome (TS) such as short stature, webbed neck and congenital heart defects. TS is an entity with decreased growth hormone (GH) responsiveness. Whether this is found in NS is debated.

METHODS

Data were retrieved from combined intervention studies including 25 children diagnosed with NS, 40 diagnosed with TS, and 45 control children (all prepubertal). NS-children and TS-girls were rhGH treated after investigation of the GH/IGFI-axis. GH was measured with poly- and monoclonal antibodies; 24hGH-profile pattern analysed by PULSAR. The NS-children were randomly assigned to Norditropin^® 33 or 66 μg/kg/day, and TS-girls were consecutively treated with Genotropin^® 33 or 66 μg/kg/day.

RESULTS

Higher PULSAR-estimates of 24h-profiles were found in both NS-children and TS-girls compared to controls: Polyclonal GH_max24h-profile (Mean ± SD) was higher in both groups (44 ± 23mU/L, p<0.01 in NS; 51 ± 47, p<0.001 in TS; compared to 30 ± 23 mU/L in controls) as was GH-baseline (1.4 ± 0.6 mU/L in NS; 2.4 ± 2.4 mU/L in TS, p<0.01 for both, compared to 1.1 ± 1.2 mU/L in controls). Pre-treatment IGFI_SDS was 2.2 lower in NS-children (-1.7 ± 1.3) compared to TS-girls (0.6 ± 1.8, p<0.0001). GH_max, IGFI/IGFBP3-ratio_SDS, and chronological age at start of GH accounted for 59% of the variance in first-year growth response in NS.

CONCLUSION

Both prepubertal NS-children and TS-girls had a high GH secretion, but low IGFI/IGFBP3 levels only in NS-children. Both groups presented a broad individual response. NS-children showed higher response in IGFI and growth, pointing to higher responsiveness to GH treatment than TS-girls.

Efficacy and safety of fermented oyster extract for height of children with short stature: a randomized placebo-controlled trial

Background

Some experimental studies have established the effect of oysters on the promotion of body growth. Yet, there is a lack of human clinical studies. The objective of this study was to evaluate the effect of a fermented oyster (FO) extract on the increase in the height of children with stature in the 25th percentile by age.

Methods

In total, 100 children (6–11 years old) were randomly divided into two (FO or control) groups. For 24 weeks, the subjects in the FO group took the FO extract once daily before sleeping, whereas the control group took placebo extracts, simultaneously. We evaluated the height gain, height velocity (HV), height standard deviation score (SDS), urine deoxypyridinoline (DPD), growth hormone (GH), insulin-like growth factor (IGF-1), and IGF binding protein 3 (IGFBP-3).

Results

The height gain and height SDS were significantly higher in the FO group than in the placebo group after 24 weeks (height gain: p < 0.001, height SDS: p < 0.005). The HV was also significantly higher in the FO group than in the placebo group after the 6th and 24th week (p = 0.001, p = 0.004). After 24 weeks, we observed a decrease in GH, IGF, and IGFBP-3 in both groups. However, serum IGFBP-3 level in the FO group reduced less than placebo group.

Conclusion

FO supplementation may help to increase the height of children, and the effect might be mediated via effects on the IGFBP-3 levels.

Factors affecting bone age maturation during 3 years of growth hormone treatment in patients with idiopathic growth hormone deficiency and idiopathic short stature: Analysis of data from the LG growth study

To investigate the progression rate of bone age (BA) and associated factors during the first 3 years of growth hormone (GH) treatment in children with idiopathic GH deficiency (iGHD) and idiopathic short stature (ISS).Data for prepubertal children with iGHD and ISS who were treated with recombinant human GH were obtained from the LG Growth Study Database and analyzed. Height, weight, BA, insulin-like growth factor-1 (IGF-1) level, and GH dose were recorded every 6 months. Differences between BA and chronological age (CA), BA-CA, were calculated at each measurement. This study included 92 (78 iGHD and 14 ISS) subjects.After 3 years of GH treatment, the height z-score was -1.09 ± 0.71 (P < .001 compared to baseline), BA-CA was -1.21 ± 1.18 years (P < .001), and IGF-1 standard deviation score (SDS) was 0.43 ± 1.21 (P < .001) in the iGHD subjects; the change in BA over the 3 years was 3.68 ± 1.27 years. In the ISS subjects, the height z-score was -1.06 ± 0.59 (P < .001), BA-CA was -0.98 ± 1.23 years (P = .009), and IGF-1 SDS was 0.16 ± 0.76 (P = .648); the change in BA over the 3 years was 3.88 ± 1.36 years. The only significant factor associated with the BA progression was the BA-CA at 1 year of GH treatment (OR = 2.732, P = .001). The baseline BA-CA, IGF-1 SDS, and GH dose did not influence BA progression.Prepubertal subjects with iGHD and ISS showed height improvement and mild BA acceleration over the first 3 years of GH treatment. However, because the BA progression rate was considered to be clinically acceptable, GH treatment may increase the predicted adult height during this period.

GH Dose Reduction Maintains Normal Prepubertal Height Velocity After Initial Catch-Up Growth in Short Children

CONTEXT

GH responsiveness guides GH dosing during the catch-up growth (CUG) period; however, little is known regarding GH dosing during the prepubertal maintenance treatment period.

OBJECTIVE

To evaluate whether SD score (SDS) channel parallel growth with normal height velocity can be maintained after CUG by reducing the GH dose by 50% in children receiving doses individualized according to estimated GH responsiveness during the catch-up period.

DESIGN AND SETTINGS

Prepubertal children (n = 98; 72 boys) receiving GH during CUG (GH deficient, n = 33; non-GH deficient, n = 65), were randomized after 2 to 3 years to either a 50% reduced individualized dose (GHRID; n = 27; 20 boys) or unchanged individualized dose (GHUID; n = 38; 27 boys). Another 33 children (25 boys) continued a standard weight-based dose [43 µg/kg/d (GHFIX)].

MAIN OUTCOME MEASURES

The primary endpoint was the proportion of children with ΔheightSDS within ±0.3 at 1 year after GH dose reduction compared with two control groups: GHUID and GHFIX. The hypothesis was that heightSDS could be maintained within ±0.3 with a reduced individualized GH dose.

RESULTS

For the intention-to-treat population at 1 year, 85% of the GHRIDgroup maintained ΔheightSDS within ±0.3 vs 41% in the GHUIDgroup (P = 0.0055) and 48% in the GHFIXgroup (P = 0.0047). The ΔIGF-ISDS in the GHRID group was -0.75 ± 1.0 at 3 months (P = 0.003) and -0.72 ± 1.2 at 1 year compared with the GHUID group (0.15 ± 1.2; P = 0.005) and GHFIX group (0.05 ± 1.0; P = 0.02).

CONCLUSIONS

Channel parallel growth (i.e., normal height velocity) and IGF-ISDS levels within ±2 were maintained after completed CUG using a 50% lower individualized dose than that used during the CUG period.

Cost-Conscious Growth-Promoting Treatment: When Discretion Is the Better Part of Value

Assessing cost-effectiveness of human growth hormone (hGH) treatment to augment height is complicated by uncertainty about how best to measure its therapeutic effect. Cost-conscious growth promotion practice, however, is possible and likely an emerging practical requisite as health care payers increasingly deny the medical necessity of and restrict support for short stature treatment. The increase in denials is not surprising given the expansion and continued high cost of hGH treatment, debate about the value of such treatment, and universal need to restrain burgeoning health care costs. Renunciation of sweeping payer rejection of hGH-for-height treatment is strengthened by cost-conscious practices that (1) recommend no treatment for most short children and restrict treatment to severe, likely disabling short stature; (2) initiate hGH treatment only after evidence-based informed assent; (3) utilize alternative less costly and less invasive options when possible; (4) minimize hGH treatment duration and dosage; and (5) resist enhancement of normal adult stature. A new era of cost-conscious hGH prescribing that prompts thoughtful restraint in hGH use could help preserve hGH approval for children most in need of treatment.

Variation of bone acquisition during growth hormone treatment in children can be explained by proteomic biomarkers, bone formation markers, body composition and nutritional factors

OBJECTIVE

Growth hormone (GH) regulates both longitudinal growth and bone acquisition in children, and has profound metabolic effects. The aim was to investigate the association between proteomic biomarkers, body fat, nutrition and bone formation markers, and longitudinal growth in response to GH during the first year of treatment. The degree to which changes in these factors could explain variations in GH-dependent longitudinal growth and bone mineralization was also assessed.

METHODS

The individualized GH dose trial included 128 short prepubertal children with either normal (non-GH-deficient) or reduced levels of GH secretion (GH-deficient) (mean age ± SD, 8.6 ± 2.6 years; 90 boys), i.e., with a broad range of GH-secretion and GH-responsiveness, receiving GH treatment (mean 43 μg/kg/day). Blood samples were taken and dual-energy X-ray absorptiometry (DXA) measured at baseline and 1 year of treatment. Step-wise multiple regression models were constructed including three steps with different independent variables added at each step to explain the variance in outcome variables (height_SDS, bone mineral content (BMC) and bone mineral density (BMD). Independent variables included in Step I were previously identified proteomic markers related to GH treatment response, bone formation markers (intact PINP, bone-specific alkaline phosphatase and osteocalcin), variables at treatment start (GH dose mU/kg/day, GH maximum secretion, and difference between child's current and mid-parental height_SDS). Step II explored the added influence of body composition data (body mass index or DXA). Step III explored the added influence of serum nutritional markers and hormones.

RESULTS

Step I variables explained 71% of the variation in first year height_SDS gain, median (minimum-maximum) 0.8 (0.24-1.67); and the proportion explained rose to 73% following inclusion of step II variables and 75% following step III. Corresponding values for total body BMC were 58%, 78%, and 80%, respectively. Proportions fell by approximately 20% when BMC was adjusted for height; 33%, 57%, and 57% for steps I, II, and III, respectively. Corresponding values for total body BMD were 29%, 39%, and 45%, respectively.

CONCLUSION

For total BMC, as much as 80% of the variation during the first year of GH treatment could be explained by proteomic biomarkers, body fat, nutrition and bone formation markers, whereas for height-adjusted BMC 57% could be explained. The inclusion of information about either body composition (fat/lean mass) or nutritional markers contributed with approximately 20%. The variation in height_SDS gain could be explained to 75%. Hence, information of fat or nutrition markers was needed for explaining the variation in bone acquisition to the same magnitude as explaining the variation in height response.

Efficacy and safety of recombinant human growth hormone in treating Chinese children with idiopathic short stature

OBJECTIVE

This study aims to investigate the efficacy and safety of recombinant human growth hormone (rhGH) in the treatment of idiopathic short stature (ISS).

METHODS

The data of 200 ISS children, who were treated with rhGH from January 2008 to December 2016, were collected and retrospectively analyzed. The data of height, bone age(BA), chronological age(CA), fasting blood glucose, fasting insulin, thyroid function and IGF-1 were collected, and annual growth velocity (GV), height standard deviation score (HtSDS) and related factors that affect GV were statistically analyzed.

RESULTS

(1) GV and HtSDS changes: As the time of treatment increased, the GV decreased year by year. The GV in the second year was significantly lower than that in the first year (P < .0001), and the GV in the fourth year was significantly lower than that in the third year (P < .05). HtSDS gradually increased from the first year to the third year, and became significantly higher than that in the year before the treatment (P < .01). The difference in the increase in HtSDS between the fourth year and third year was not statistically significant (P > .05). (2) The influence factors of GV included age at initial treatment, IGF-1SDS during treatment and GV in the year before treatment. (3) The most common side effects during treatment included transient hyperglycemia and temporary hyperinsulinemia, and these returned to normal after the treatment was stopped. Some patients presented with accelerated bone age growth after two years of treatment (annual growth of bone age △BA was >2 years), compared with children without accelerated bone age growth, and the difference between BA and CA (BA-CA) was significantly reduced at the beginning of the treatment (P < .01).

CONCLUSION

rhGH has a good growth promoting effect on ISS children. A variety of factors may affect the GV, and related adverse reactions should be monitored during the treatment.

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.

Growth Hormone Research Society perspective on biomarkers of GH action in children and adults

OBJECTIVE

The Growth Hormone Research Society (GRS) convened a Workshop in 2017 to evaluate clinical endpoints, surrogate endpoints and biomarkers during GH treatment of children and adults and in patients with acromegaly.

PARTICIPANTS

GRS invited 34 international experts including clinicians, basic scientists, a regulatory scientist and physicians from the pharmaceutical industry.

EVIDENCE

Current literature was reviewed and expert opinion was utilized to establish the state of the art and identify current gaps and unmet needs.

CONSENSUS PROCESS

Following plenary presentations, breakout groups discussed questions framed by the planning committee. The attendees re-convened after each breakout session to share the group reports. A writing team compiled the breakout session reports into a document that was subsequently discussed and revised by participants. This was edited further and circulated for final review after the meeting. Participants from pharmaceutical companies were not part of the writing process.

CONCLUSIONS

The clinical endpoint in paediatric GH treatment is adult height with height velocity as a surrogate endpoint. Increased life expectancy is the ideal but unfeasible clinical endpoint of GH treatment in adult GH-deficient patients (GHDA) and in patients with acromegaly. The pragmatic clinical endpoints in GHDA include normalization of body composition and quality of life, whereas symptom relief and reversal of comorbidities are used in acromegaly. Serum IGF-I is widely used as a biomarker, even though it correlates weakly with clinical endpoints in GH treatment, whereas in acromegaly, normalization of IGF-I may be related to improvement in mortality. There is an unmet need for novel biomarkers that capture the pleiotropic actions of GH in relation to GH treatment and in patients with acromegaly.

Using a spontaneous profile rather than stimulation test makes the KIGS idiopathic growth hormone deficiency model more accessible for clinicians

AIM

Children treated with a growth hormone (GH) for idiopathic growth hormone deficiency (IGHD) may be monitored with the first-year prediction model from the Pfizer International Growth Database (KIGS) using auxology, age, GH dose and the maximum GH concentration from a stimulation test (GH_max stim). We tested the hypothesis that using a 12-hour spontaneous profile (GH_max 12h) would be as accurate.

METHODS

We studied 98 prepubertal Swedish children (78 boys) aged 2-12 years enrolled in KIGS. The first-year growth was predicted using the GH_max from the GH profile and a stimulation test, and both of these were compared separately with the observed growth response.

RESULTS

The increased height observed in the first year was 0.74 standard deviation scores (SDS), and the studentised residuals for the predicted and observed growth with GH_max stim (-0.16 SDS) and GH_max 12h (-0.22) were similar. Individual predictions calculated with stimulated or spontaneous GH_max showed a significant correlation (r = 0.80).

CONCLUSION

We validated the KIGS IGHD prediction model and found that the stimulated GH_max peak can be reliably replaced by the GH_max 12h with similar accuracy. This makes the model more accessible for clinicians, who can then provide realistic expectations for the growth response during the first year of treatment.

Early cessation and non-response are important and possibly related problems in growth hormone therapy: An OZGROW analysis

OBJECTIVE

To investigate growth hormone (GH) treatment and treatment cessation with respect to efficacy and efficiency. To identify factors that best classify or predict cessation type: completed treatment (CT), early cessation (EC), or non-response (NR).

DESIGN

Observational study (1990-2013) of the Australian GH Program comparing CT, EC, and NR groups with respect to demographic, clinical, and response criteria. All patients treated for GH deficiency (GHD; 909), short stature and slow growth (SSSG; 2144), and Turner Syndrome (TS; 626) were included. Information was retrieved from the OZGROW database.

RESULTS

51.9% of patients were EC, 40.7% CT and 7.4% NR.Median treatment durations for NR patients were often longer than patients who completed treatment. EC and NR groups were both associated with poor growth response with males overrepresented.Socioeconomic status differentiated NR (higher) and EC (lower) groups.

CONCLUSIONS

EC was observed at very high rates and appears, generally, to be a little-recognised but frequent problem in GH therapy.EC and delayed recognition of NR may be interrelated being differentiated by the decision to cease or continue treatment following poor response.Poor treatment compliance is likely a major causal factor in EC.Strategies to address poor response and compliance have been developed, however, given the scale of these problems, it may be that long acting GH formulations or individualized treatment need consideration.

The P2 promoter of the IGF1 gene is a major epigenetic locus for GH responsiveness

Short children using growth hormone (GH) to accelerate their growth respond to this treatment with a variable efficacy. The causes of this individual variability are multifactorial and could involve epigenetics. Quantifying the impact of epigenetic variation on response to treatments is an emerging challenge. Here we show that methylation of a cluster of CGs located within the P2 promoter of the insulin-like growth factor 1 (IGF1) gene, notably CG-137, is inversely closely correlated with the response of growth and circulating IGF1 to GH administration. For example, variability in CG-137 methylation contributes 25% to variance of growth response to GH. Methylation of CGs in the P2 promoter is negatively associated with the increased transcriptional activity of P2 promoter in patients' mononuclear blood cells following GH administration. Our observation indicates that epigenetics is a major determinant of GH signaling (physiology) and of individual responsiveness to GH treatment (pharmacoepigenetics).

Growth hormone (GH) dose-dependent IGF-I response relates to pubertal height gain

BACKGROUND

Responsiveness to GH treatment can be estimated by both growth and ∆IGF-I. The primary aim of the present study was to investigate if mimicking the physiological increase during puberty in GH secretion, by using a higher GH dose could lead to pubertal IGFs in short children with low GH secretion. The secondary aim was to explore the relationship between IGF-I, IGFBP-3 and the IGF-I/IGFBP-3 ratio and gain in height.

METHODS

A multicentre, randomized, clinical trial (TRN88-177) in 104 children (90 boys), who had received GH 33 μg/kg/day during at least 1 prepubertal year. They were followed from GH start to adult height (mean, 7.5 years; range, 4.6-10.7). At onset of puberty, children were randomized into three groups, to receive 67 μg/kg/day (GH(67)) given once (GH(67x1); n = 30) or divided into two daily injection (GH(33x2); n = 36), or to remain on a single 33 μg/kg/day dose (GH(33x1); n = 38). The outcome measures were change and obtained mean on-treatment IGF-I(SDS), IGFBP3(SDS) and IGF-I/IGFBP3 ratio(SDS) during prepuberty and puberty. These variables were assessed in relation to prepubertal, pubertal and total gain in heightSDS.

RESULTS

Mean prepubertal increases 1 year after GH start were: 2.1 IGF-I(SDS), 0.6 IGFBP3(SDS) and 1.5 IGF-I/IGFBP3ratio(SDS). A significant positive correlation was found between prepubertal ∆IGFs and both prepubertal and total gain in height(SDS). During puberty changes in IGFs were GH dose-dependent: mean pubertal level of IGF-I(SDS) was higher in GH(67) vs GH(33) (p = 0.031). First year pubertal ∆IGF-I(SDS) was significantly higher in the GH(67)vs GH(33) group (0.5 vs -0.1, respectively, p = 0.007), as well as ∆IGF-I(SDS) to the pubertal mean level (0.2 vs -0.2, p = 0.028). In multivariate analyses, the prepubertal increase in '∆IGF-I(SDS) from GH start' and the 'GH dose-dependent pubertal ∆IGF-I(SDS)' were the most important variables for explaining variation in prepubertal (21 %), pubertal (26 %) and total (28 %) gain in height(SDS).

TRIAL REGISTRATION

TRN 88-177, not applicable 1988.

CONCLUSION

The dose-dependent change in IGFs was related to a dose-dependent pubertal gain in height(SDS). The attempt to mimic normal physiology by giving a higher GH dose during puberty was associated with both an increase in IGF-I and a dose-dependent gain in height(SDS).

Genetic and Epigenetic Modulation of Growth Hormone Sensitivity Studied With the IGF-1 Generation Test

CONTEXT

Like all hormones, GH has variable physiological effects across people. Many of these effects initiated by the binding of GH to its receptor (GHR) in target tissues are mediated by the expression of the IGF1 gene. Genetic as well as epigenetic variation is known to contribute to the individual diversity of GH-dependent phenotypes through two mechanisms. The first one is the genetic polymorphism of the GHR gene due to the common deletion of exon 3. The second, more recently reported, is the epigenetic variation in the methylation of a cluster of CGs dinucleotides located within the proximal part of the P2 promoter of the IGF-1 (IGF1) gene, notably CG-137.

OBJECTIVE

The current study evaluates the relative contribution of these two factors controlling individual GH sensitivity by measuring the response of serum IGF-1 to a GH injection (IGF-1 generation test) in a sample of 72 children with idiopathic short stature.

RESULTS

Although the d3 polymorphism of the GHR contributed 19% to the variance of the IGF-1 response, CG-137 methylation in the IGF-1 promoter contributed 30%, the combined contribution of the two factors totaling 43%.

CONCLUSION

Our observation indicates that genetic and epigenetic variation at the GHR and IGF-1 loci play a major role as independent modulators of individual GH sensitivity.

Sex, Sport, IGF-1 and the Community Effect in Height Hypothesis

We test the hypothesis that differences in social status between groups of people within a population may induce variation in insulin-like growth factor-1(IGF-1) levels and, by extension, growth in height. This is called the community effect in height hypothesis. The relationship between IGF-1, assessed via finger-prick dried blood spot, and elite level sport competition outcomes were analysed for a sample of 116 undergraduate men and women. There was a statistically significant difference between winners and losers of a competition. Winners, as a group, had higher average pre-game and post-game IGF-1 levels than losers. We proposed this type of difference as a proxy for social dominance. We found no evidence that winners increased in IGF-1 levels over losers or that members of the same team were more similar in IGF-1 levels than they were to players from other teams. These findings provide limited support toward the community effect in height hypothesis. The findings are discussed in relation to the action of the growth hormone/IGF-1 axis as a transducer of multiple bio-social influences into a coherent signal which allows the growing human to adjust and adapt to local ecological conditions.