Personalized approach to growth hormone treatment: clinical use of growth prediction models

Gene Expression Signatures Predict First-Year Response to Somapacitan Treatment in Children With Growth Hormone Deficiency

CONTEXT

The pretreatment blood transcriptome predicts growth response to daily growth hormone (GH) therapy with high accuracy.

OBJECTIVE

Investigate response prediction using pretreatment transcriptome in children with GH deficiency (GHD) treated with once-weekly somapacitan, a novel long-acting GH.

METHODS

REAL4 is a randomized, multinational, open-label, active-controlled parallel group phase 3 trial, comprising a 52-week main phase and an ongoing 3-year safety extension (NCT03811535). A total of 128/200 treatment-naïve prepubertal children with GHD consented to baseline blood transcriptome profiling. They were randomized 2:1 to subcutaneous somapacitan (0.16 mg/kg/week) or daily GH (0.034 mg/kg/day). Differential RNA-seq analysis and machine learning were used to predict therapy response.

RESULTS

121/128 samples passed quality control. Children treated with somapacitan (n = 76) or daily GH (n = 45) were categorized based on fastest and slowest growing quartiles at week 52. Prediction of height velocity (HV; cm/year) was excellent for both treatments (out of bag [OOB] area under curve [AUC]: 0.98-0.99; validation AUC: 0.83-0.84), as was prediction of secondary markers of growth response: HV standard deviation score (SDS) (0.99-1.0; 0.75-0.78), change from baseline height SDS (ΔHSDS) (0.98-1.0; 0.61-0.75), and change from baseline insulin-like growth factor-I SDS (ΔIGF-I SDS) (0.96-1.0; 0.85-0.88). Genes previously identified as predictive of GH therapy response were consistently better at predicting the fastest growers in both treatments in this study (OOB AUC: 0.93-0.97) than the slowest (0.67-0.85).

CONCLUSION

Pretreatment transcriptome predicts first-year growth response in somapacitan-treated children with GHD. A common set of genes can predict the treatment response to both once-weekly somapacitan and conventional daily GH. This approach could potentially be developed into a clinically applicable pretreatment test to improve clinical management.

Importance of Growth Factors and Bone Maturation Ratio in the Response to Growth Hormone Therapy

OBJECTIVE

The aim was to identify the influence of insulin-like growth factor I (IGF-1), IGF-binding protein-3 (IGFBP-3), and bone age (BA)/chronological age (CA) ratio on the response to GH therapy after 1 and 2 years of treatment and upon reaching final height.

METHODS

Longitudinal, retrospective, observational study of 139 patients treated for idiopathic growth hormone deficiency. Variables examined during follow-up: (1) genetic background; (2) perinatal history; (3) anthropometry; (4) height velocity, BA, BA/CA and height prognosis; (5) analytical results (IGF-1, IGFBP-3). Final response variables: adult height (AH), AH with respect to target height, AH with respect to initial height prognosis, AH with respect to height at the start of treatment, and AH with respect to height at onset of puberty.

RESULTS

Lower pretreatment IGF-1 levels and a greater increase in IGF-1 at the end of treatment imply a better response (r = -0.405, P = .007 and r = 0.274, P = .014, respectively), as does a greater increase in IGFBP-3 after 2 years of treatment and at the end of treatment (r = 0.207, P = .035 and r = 0.259, P = .020, respectively). A lower BA/CA ratio pretreatment and at the onset of puberty results in a better response (r = -0.502, P = .000 and r = -0.548, P = .000, respectively), as does a lower increase in BA and BA/CA ratio after the 1 and 2 years of treatment (r = -0.337, P = .000 and r = -0.332, P = .000, respectively).

CONCLUSION

Low pretreatment IGF-1, a greater BA delay with respect to CA pretreatment and at the onset of puberty, a greater increase in IGFBP-3 after 2 years of treatment, and a lower increase in BA and BA/CA ratio after 1 and 2 years of treatment imply a better long-term response.

Comparison of two prediction models in a clinical setting to predict growth in prepubertal children on recombinant growth hormone

OBJECTIVE

Prediction models that calculate the growth response in children on recombinant growth hormone (GH) have shown to be helpful tools in deciding who should start treatment, as identifying GH deficiency can be a challenge. The aim of the study is to compare two prediction models; the KIGS (Pfizer International Growth Study) prediction models which are more accessible and the Gothenburg model which has previously been clinically validated.

DESIGN

All prepubertal patients who commenced GH treatment at Queen Silvia Children's Hospital in Gothenburg during a 13-year-period were candidates for the study. Children were excluded if suspected syndrome, malignant disease, chronic disease, or poor adherence to treatment were found. The KIGS model and the Gothenburg model were used to make predictions. Data was obtained from medical charts for the period from birth to the end of the first year of treatment. The predicted height outcome was compared against observed.

RESULTS

The study included 123 prepubertal children (76 males). The average age at treatment start and standard deviation (SD) was 5.7 (1.8) years. Correlation analyses were performed between predicted growth by both the Gothenburg and KIGS models versus the first year observed growth response showing strong correlations of r = 0.990 and r = 0.991 respectively with studentized residuals of 0.10 (0.81) for the Gothenburg model and 0.03 (0.96) for the KIGS model.

CONCLUSION

We found that both the Gothenburg model and the KIGS model are equivalent when applying to our clinical cohort. Both models are very precise, hence it is encouraged to use either based on accessibility for the clinic.

Development and validation of a nomogram to predict poor short-term response to recombinant human growth hormone treatment in children with growth disorders

PURPOSE

The purpose of this study was to develop and validate a clinical predictive model for predicting the likelihood of a poor therapeutic response during the first year of recombinant human growth hormone (rhGH) treatment in children with growth disorders.

METHODS

A total of 627 pediatric patients with growth disorders (GHD, ISS, TS, SGA) from The LG Growth Study cohort were evaluated. Restricted cubic splines (RCS) were utilized to investigate the association between predictors and the risk of poor rhGH response. Variables were selected using LASSO regression, and multivariate logistics regression models were established. Receiver operating characteristic (ROC) curves, calibration curves, decision curve analysis (DCA), and clinical impact curves (CIC) were used to assess the predictive model's accuracy and clinical value. The predictive accuracy of the model was validated on the testing set.

RESULTS

Two predictive models containing 8 baseline predictors (diagnosis, age, height SDS, bone age minus chronological age, rhGH dosage, distance from mid-parental height in SDS, weight SDS, IGF-1 SDS) and 1 post-treatment predictor (height SDS gain at 6 months) were constructed by multivariate logistic regression analyses. The nomogram was built based on the multivariate predictive model and showed good discrimination and model fit effects in both the training set and the testing set. DCA and CIC analyses presented good clinical usability.

CONCLUSION

The clinical predictive model for predicting the probability of poor short-term response of rhGH treatment in pediatric patients with growth disorders is useful and can assist physicians in making clinical decisions.

The Changing Face of Paediatric Human Growth Hormone Therapy

Human growth hormone (hGH) has been used therapeutically to promote growth in children for over 60 years. Pituitary-extracted hGH has demonstrated positive growth promotion since the early 1960s. In 1985, prion-induced contamination of hGH triggered a global epidemic of Creutzfeldt–Jakob disease that was responsible for its discontinuation. Recombinant hGH immediately replaced pituitary hGH and, being available in large amounts, was used and licenced for therapy in GH-deficient children, followed by approval for non-GH deficient disorders such as Turner syndrome, short stature related to birth size small for gestational age, idiopathic short stature, SHOX deficiency, Prader–Willi syndrome and Noonan syndrome. RhGH therapy was refined by the use of growth prediction models; however, unmet needs, such as the variability in response and non-adherence resulted in the development of long-acting rhGH (LArhGH) molecules, which are currently in clinical trials and have shown non-inferiority in comparison with daily rhGH. It is likely that LArhGH will enter clinical practice in 2022 and 2023 and will need to demonstrate safety in terms of immunogenicity, IGF-1 generation, metabolic status and tolerability of potential injection pain and local reactions.

Metabolomic Differential Compounds Reflecting the Clinical Efficacy of Polyethylene Glycol Recombinant Human Growth Hormone in the Treatment of Childhood Growth Hormone Deficiency

Understanding metabolite profiles may aid in providing a reference for individualized treatment using PEG-rhGH. Therefore, this study aimed to evaluate the clinical efficacy of PEG-rhGH in treating GHD patients by using a metabolomic approach. Fifty-seven pediatric participants treated with PEG-rhGH were enrolled (28 GHD patients with high clinical efficacy and 29 GHD patients with lower clinical efficacy). Serum samples from all patients were first collected at baseline for biochemical detection; then metabolite levels were measured using gas chromatography time-of-flight mass spectrometry. The candidates included heptadecanoic acid, stearic acid, 2-hydroxybutyric acid, myristic acid, palmitoleic acid, D-galactose, dodecanoic acid, and oleic acid. The related metabolic pathways involved fatty acid metabolism and energy metabolism. This study suggested that growth gains of PEG-rhGH treatment might be differentiated by altered serum levels of fatty acid. Collectively, the metabolomic study provides unique insights into the use of PEG-rhGH as a therapeutic strategy for individualized treatment.

Approach to the Patient: Safety of Growth Hormone Replacement in Children and Adolescents

The use of recombinant human growth hormone (rhGH) in children and adolescents has expanded since its initial approval to treat patients with severe GH deficiency (GHD) in 1985. rhGH is now approved to treat several conditions associated with poor growth and short stature. Recent studies have raised concerns that treatment during childhood may affect morbidity and mortality in adulthood, with specific controversies over cancer risk and cerebrovascular events. We will review 3 common referrals to a pediatric endocrinology clinic, followed by a summary of short- and long-term effects of rhGH beyond height outcomes. Methods to mitigate risk will be reviewed. Finally, this information will be applied to each clinical case, highlighting differences in counseling and clinical outcomes. rhGH therapy has been used for more than 3 decades. Data are largely reassuring, yet we still have much to learn about pharmaceutical approaches to growth in children and the lifelong effect of treatment.

A prediction model could foresee adequate height response in children eligible for growth hormone treatment

AIM

Prediction models may be useful in accurately identifying children who will benefit from growth hormone (GH) treatment. We aimed to validate the Gothenburg prediction model for this purpose.

METHODS

The study included prepubertal children with GH deficiency who started treatment with GH during 2004-2016 at Queen Silvia Children's Hospital, Gothenburg, based on a first-year growth prediction of ≥0.7 SDS in height according to the Gothenburg prediction model on a GH dose of 33 μg/kg/day. Observed heights retrieved from medical charts were compared with predicted heights.

RESULTS

The study included 121 patients (64% boys) with at least one year of data after the start of GH treatment. The median (range) GH dose was 30 (10-43) µg/kg/day for the first year and age at start of treatment was 5.32 (3-11.8) years. The model correctly excluded poor responders resulting in 119/121 (98%) patients having a height gain of at least ≥0.5 SDS in a year. However, the model underestimated relatively low predictions and overestimated relatively high predictions, with a residual standard deviation of 0.31 SDS.

CONCLUSION

By using a validated prediction model for GH in a clinical context, unnecessarily treating short children with an expected poor height outcome can be avoided.

The history, physiology and treatment safety of growth hormone

Growth hormone treatment was introduced in the 1950s to address growth disturbances and metabolic abnormalities. Hundreds of thousands of children have been treated, with gradual expansion of treatment indications. From initially being offered only to patients with severe growth hormone deficiency, today many children are treated for conditions in which the associated short stature is not primarily thought to be due to deficient endogenous growth hormone secretion. This review discusses the history, physiology and safety of growth hormone treatment, with focus on the long-term risks of mortality, cardiovascular morbidity and cancer. Conclusion: Continuous follow-up is needed to increase our knowledge of the long-term treatment safety.

Inclusion and Withdrawal Criteria for Growth Hormone (GH) Therapy in Children with Idiopathic GH Deficiency—Towards Following the Evidence but Still with Unresolved Problems

According to current guidelines, growth hormone (GH) therapy is strongly recommended in children and adolescents with GH deficiency (GHD) in order to accelerate growth rate and attain normal adult height. The diagnosis of GHD requires demonstration of decreased GH secretion in stimulation tests, below the established threshold value. Currently, GHD in children is classified as secondary insulin-like growth factor-1 (IGF-1) deficiency. Most children diagnosed with isolated GHD present with normal GH secretion at the attainment of near-final height or even in mid-puberty. The most important clinical problems, related to the diagnosis of isolated GHD in children and to optimal duration of rhGH therapy include: arbitrary definition of subnormal GH peak in stimulation tests, disregarding factors influencing GH secretion, insufficient diagnostic accuracy and poor reproducibility of GH stimulation tests, discrepancies between spontaneous and stimulated GH secretion, clinical entity of neurosecretory dysfunction, discrepancies between IGF-1 concentrations and results of GH stimulation tests, significance of IGF-1 deficiency for the diagnosis of GHD, and a need for validation IGF-1 reference ranges. Many of these issues have remained unresolved for 25 years or even longer. It seems that finding solutions to them should optimize diagnostics and therapy of children with short stature.

Curve matching to predict growth in patients receiving growth hormone therapy: An interpretable & explainable method

Curve matching may be used to predict growth outcomes using data of patients whose growth curves resemble those of a new patient with growth hormone deficiency (GHD) and those born small for gestational age (SGA). We aimed to investigate the validity of curve matching to predict growth in patients with GHD and those born SGA receiving recombinant human growth hormone (r-hGH). Height data collected between 0-48 months of treatment were extracted from the easypod™ connect ecosystem and the easypod™ connect observational study. Selected patients with height standard deviation scores (HSDS) [-4, <-1] and age [3, <16y] at start were included. The 'Matching Database' consisted of patients' monthly HSDS obtained by the broken stick method and imputation. Standard deviation (SD) was obtained from the observed minus the predicted HSDS (error) based on matched patients within the 'Matching Database'. Data were available for 3,213 patients in the 'Matching Database', and 2,472 patients with 16,624 HSDS measurements in the observed database. When ≥2 HSDS measurements were available, the error SD for a one-year prediction was approximately 0.2, which corresponds to 1.1 cm, 1.3 cm, and 1.5 cm at 7, 11, and 15 years of age, respectively. Indication and age at treatment start (<11 vs ≥11 years) had a small impact on the error SD, with patients born SGA and patients aged <11 years at treatment start generally having slightly lower values. We conclude that curve matching is a simple and valid technique for predicting growth in patients with GHD and those born SGA.

Integrated Digital Health Solutions in the Management of Growth Disorders in Pediatric Patients Receiving Growth Hormone Therapy: A Retrospective Analysis

Digital health has seen rapid advancements over the last few years in helping patients and their healthcare professionals better manage treatment for a variety of illnesses, including growth hormone (GH) therapy for growth disorders in children and adolescents. For children and adolescents requiring such therapy, as well as for their parents, the treatment is longitudinal and often involves daily injections plus close progress monitoring; a sometimes daunting task when young children are involved. Here, we describe our experience in offering devices and digital health tools to support GH therapy across some 40 countries. We also discuss how this ecosystem of care has evolved over the years based on learnings and advances in technology. Finally, we offer a glimpse of future planned enhancements and directions for digital health to play a bigger role in better managing conditions treated with GH therapy, as well as model development for adherence prediction. The continued aim of these technologies is to improve clinical decision making and support for GH-treated patients, leading to better outcomes.

Weekly Lonapegsomatropin in Treatment-Naïve Children With Growth Hormone Deficiency: The Phase 3 heiGHt Trial

CONTEXT

For children with growth hormone deficiency (GHD), treatment burden with daily somatropin injections [human growth hormone (hGH)] is high, which may lead to poor adherence and suboptimal overall treatment outcomes. Lonapegsomatropin (TransCon hGH) is an investigational long-acting, once-weekly prodrug for the treatment of GHD.

OBJECTIVE

The objective of this study was to evaluate the efficacy and safety of once-weekly lonapegsomatropin vs daily somatropin.

DESIGN

The heiGHt trial was a randomized, open-label, active-controlled, 52-week Phase 3 trial (NCT02781727).

SETTING

This trial took place at 73 sites across 15 countries.

PATIENTS

This trial enrolled and dosed 161 treatment-naïve, prepubertal patients with GHD.

INTERVENTIONS

Patients were randomized 2:1 to receive lonapegsomatropin 0.24 mg hGH/kg/week or an equivalent weekly dose of somatropin delivered daily.

MAIN OUTCOME MEASURE

The primary end point was annualized height velocity (AHV) at week 52. Secondary efficacy end points included change from baseline in height SD scores (SDS).

RESULTS

Least squares (LS) mean (SE) AHV at 52 weeks was 11.2 (0.2) cm/year for lonapegsomatropin vs 10.3 (0.3) cm/year for daily somatropin (P = 0.009), with lonapegsomatropin demonstrating both noninferiority and superiority over daily somatropin. LS mean (SE) height SDS increased from baseline to week 52 by 1.10 (0.04) vs 0.96 (0.05) in the weekly lonapegsomatropin vs daily somatropin groups (P = 0.01). Bone age/chronological age ratio, adverse events, tolerability, and immunogenicity were similar between groups.

CONCLUSIONS

The trial met its primary objective of noninferiority in AHV and further showed superiority of lonapegsomatropin compared to daily somatropin, with similar safety, in treatment-naïve children with GHD.

Growth hormone deficit. Does the first year of treatment influence adult height?

INTRODUCTION

Short stature is the most frequent reason for Pediatric Endocrinology consultations and sometimes requires treatment with growth hormone.

OBJECTIVE

The possible correlation of a good response to any early response factor with a better final response was studied, and also whether there was a difference in response to treatment according to the type of deficit.

PATIENTS AND METHODS

This was a longitudinal, retrospective and observational study of 139 patients treated for idiopathic growth hormone deficiency up to adult height. There were good response criteria in the first year of treatment: a) an increase in growth rate ≥3 cm/year, b) a growth rate ≥1 standard deviation (SD), c) an increase in height ≥0.5 SD, d) an increase in height ≥0.3 SD. Study of the Index of Responsiveness to treatment in the first and second year. Final response variables: adult height with respect to target height, adult height with respect to initial growth prediction and adult height with respect to initial height at the start of treatment. The possible correlation of a good response to any of the early response factors with a better final response to treatment was studied, and also whether there was a difference in the response to treatment according to the type of deficit.

RESULTS

The treatment produced a gain in adult height with respect to genetic height of 0.06 ± 0.7 SD. Patients considered good responders in the first year of treatment presented a better final response (growth rate ≥3 cm: p = 0.000, growth rate ≥1 SD: p = 0.008, height gain ≥0.5 SD: p = 0.007, height gain ≥0.3 SD: p = 0.006), as well as patients with a severe deficit (p = 0.04). The index of responsiveness to treatment during the first year was associated with a better final response (r = 0.249, p = 0.003), with this correlation being maintained in the second year (r = 0.294, p = 0.01).

CONCLUSIONS

Growth hormone treatment increased height in the genetic target. The percentage of good responders varied depending on the criteria used. The response in the first year of treatment and a severe deficit were determining factors for achieving a good long-term response.

Gene expression signatures predict response to therapy with growth hormone

Recombinant human growth hormone (r-hGH) is used as a therapeutic agent for disorders of growth including growth hormone deficiency (GHD) and Turner syndrome (TS). Treatment is costly and current methods to model response are inexact. GHD (n = 71) and TS patients (n = 43) were recruited to study response to r-hGH over 5 years. Analysis was performed using 1219 genetic markers and baseline (pre-treatment) blood transcriptome. Random forest was used to determine predictive value of transcriptomic data associated with growth response. No genetic marker passed the stringency criteria for prediction. However, we identified an identical set of genes in both GHD and TS whose expression could be used to classify therapeutic response to r-hGH with a high accuracy (AUC > 0.9). Combining transcriptomic markers with clinical phenotype was shown to significantly reduce predictive error. This work could be translated into a single genomic test linked to a prediction algorithm to improve clinical management. Trial registration numbers: NCT00256126 and NCT00699855.

Comparison of the Effectiveness of Adult Height Prediction Methods in Children with Growth Hormone Deficiency

Background: In patients with growth hormone (GH) deficiency, the prediction of adult height before initiation of GH treatment can be helpful to guide clinicians and families. However, data regarding the effectiveness of prediction methods in such patients are limited.Objective: We aimed to investigate the accuracy of the three most used adult height prediction methods [Bayley-Pinneau (BP), Roche-Wainer-Thissen (RWT), and Tanner-Whitehouse 2 (TW2)] by comparing their results with the near-adult height (NAH) data of children treated with GH.Methods: A single-center retrospective study was conducted including patients treated with somatotropin due to GH deficiency. Bone age radiographs were reread by three authors. Adult height predictions were made using BP, RWT, and TW2 methods for each patient.Results: Forty-nine patients with GH deficiency [median age at diagnosis 10.8 (9.2-12.0) years, 63.3% girls, 69.4% prepubertal] were included. Median differences between predicted adult height (PAH) and NAH standard deviation (SD) scores were -0.5, 0.0, and 0.3 for BP, RWT, and TW2 methods, respectively. The rates of PAH within ±1 SD score of NAH were 54.7%, 62.3%, and 77.4% for BP, TW2, and RWT methods, respectively. RWT was the most accurate method in girls, however, it showed a similar efficiency with TW2 in prepubertal patients or those with delayed bone age between 1-2 years, independent of gender.Conclusions: We found that RWT and TW2 methods may be preferable rather than the BP method for predicting adult height in patients with a diagnosis of GH deficiency.

Effects of Recombinant Human Growth Hormone Treatment, Depending on the Therapy Start in Different Nutritional Phases in Paediatric Patients with Prader-Willi Syndrome: A Polish Multicentre Study

Recombinant human growth hormone (rhGH) treatment is an established management in patients with Prader-Willi syndrome (PWS), with growth promotion and improvement in body composition and possibly the metabolic state. We compared anthropometric characteristics, insulin-like growth factor 1 (IGF1) levels, metabolic parameters and the bone age/chronological age index (BA/CA) in 147 children with PWS, divided according to age of rhGH start into four groups, corresponding to nutritional phases in PWS. We analysed four time points: baseline, rhGH1 (1.21 ± 0.81 years), rhGH2 (3.77 ± 2.17 years) and rhGH3 (6.50 ± 2.92 years). There were no major differences regarding height SDS between the groups, with a higher growth velocity (GV) (p = 0.00) and lower body mass index (BMI) SDS (p < 0.05) between the first and older groups during almost the whole follow-up. IGF1 SDS values were lower in group 1 vs. other groups at rhGH1 and vs. groups 2 and 3 at rhGH2 (p < 0.05). Glucose metabolism parameters were favourable in groups 1 and 2, and the lipid profile was comparable in all groups. BA/CA was similar between the older groups. rhGH therapy was most effective in the youngest patients, before the nutritional phase of increased appetite. We did not observe worsening of metabolic parameters or BA/CA advancement in older patients during a comparable time of rhGH therapy.

Development of a Predictive Enrichment Marker for the Oral GH Secretagogue LUM-201 in Pediatric Growth Hormone Deficiency

Context

We hypothesize, based on the degree of residual hypothalamic-pituitary function, that some, but not all, children with growth hormone deficiency (GHD) may have beneficial growth responses to the orally administered growth hormone (GH) secretagogue LUM-201.

Objective

To determine if pretreatment testing can identify predictive enrichment markers (PEM) for subjects with adequate residual function who are responsive to LUM-201.

Methods

We performed an analysis of a completed, randomized, placebo-controlled trial of LUM-201, a GH secretagogue receptor agonist, in which all randomized subjects had pretreatment testing.

This international multicenter study conducted in pediatric endocrinology clinics included 68 naïve-to-treatment, prepubertal children with established diagnoses of GHD. Outcome measures included the sensitivity, specificity, and predictive accuracy of potential markers to predict 6-month growth responses to oral LUM-201 and daily rhGH.

Results

Two PEM were identified for use in defining PEM-positive status: (1) baseline insulin-like growth factor I (IGF-I) concentration >30 ng/mL and (2) peak GH response of ≥5 ng/mL upon administration of single-dose LUM-201. PEM-positive status enriches a population for better growth responses to LUM-201. PEM-negative status enriches a population for better growth responses to rhGH.

Conclusion

Combined, the peak GH response to single-dose LUM-201 and the baseline IGF-I concentration are effective PEMs for 6-month growth responses to LUM-201 and rhGH in prepubertal children with GHD.

Corroboration of Height Velocity Prediction Markers for rhGH With an Oral GH Secretagogue Treatment in Children With GHD

Context

Recombinant human growth hormone (rhGH) is approved for treatment of pediatric growth hormone deficiency (GHD), with greatest growth responses observed in those with severe GHD. Orally administered GH secretagogues (GHS) may be useful treatment in patients with moderate GHD. Distinguishing children with severe vs moderate GHD could identify children who would be better treated with rhGH or GHS.

Objectives

Evaluate baseline insulin-like growth factor-I (IGF-I) and stimulated peak GH response as predictors of 12-month height velocity (HV) in children with GHD.

Design

Data on children with GHD were analyzed in a legacy data base (GeNeSIS data).

Participants

514 naïve to rhGH-treatment, prepubertal children with idiopathic isolated GHD for whom stimulated GH, baseline serum IGF-I, and first-year HV during rhGH treatment data are available.

Outcome Measures

Children with severe or moderate GHD were categorized based on GH and IGF-I data and evaluated based on baseline auxologic and hormone profiles and first-year growth response to rhGH.

Results

Cohorts of severe and moderate GHD were 81/514 (15.8%) and 433/514 (84.2%). Cohorts differed significantly with regard to indicators of GHD [eg, baseline height SD score (SDS), height SDS minus target height SDS, HV, HV SDS, and change in height SDS during rhGH treatment]. Multiple regression analysis showed IGF-I and stimulated GH were significant predictors of HV independent of other known variables. Expected first-year HV in moderate GHD was 8.3 cm/y.

Conclusions

The combination of peak GH to GH stimulation testing and baseline IGF-I concentration are predictive enrichment markers for annualized HV responses to rhGH therapy.

Important Tools for Use by Pediatric Endocrinologists in the Assessment of Short Stature

Assessment and management of children with growth failure has improved greatly over recent years. However, there remains a strong potential for further improvements by using novel digital techniques. A panel of experts discussed developments in digitalization of a number of important tools used by pediatric endocrinologists at the third 360° European Meeting on Growth and Endocrine Disorders, funded by Merck KGaA, Germany, and this review is based on those discussions. It was reported that electronic monitoring and new algorithms have been devised that are providing more sensitive referral for short stature. In addition, computer programs have improved ways in which diagnoses are coded for use by various groups including healthcare providers and government health systems. Innovative cranial imaging techniques have been devised that are considered safer than using gadolinium contrast agents and are also more sensitive and accurate. Deep-learning neural networks are changing the way that bone age and bone health are assessed, which are more objective than standard methodologies. Models for prediction of growth response to growth hormone (GH) treatment are being improved by applying novel artificial intelligence methods that can identify non-linear and linear factors that relate to response, providing more accurate predictions. Determination and interpretation of insulin-like growth factor-1 (IGF-1) levels are becoming more standardized and consistent, for evaluation across different patient groups, and computer-learning models indicate that baseline IGF-1 standard deviation score is among the most important indicators of GH therapy response. While physicians involved in child growth and treatment of disorders resulting in growth failure need to be aware of, and keep abreast of, these latest developments, treatment decisions and management should continue to be based on clinical decisions. New digital technologies and advancements in the field should be aimed at improving clinical decisions, making greater standardization of assessment and facilitating patient-centered approaches.

An eHealth Framework for Managing Pediatric Growth Disorders and Growth Hormone Therapy

Background

The use of technology to support health and health care has grown rapidly in the last decade across all ages and medical specialties. Newly developed eHealth tools are being implemented in long-term management of growth failure in children, a low prevalence pediatric endocrine disorder.

Objective

Our objective was to create a framework that can guide future implementation and research on the use of eHealth tools to support patients with growth disorders who require growth hormone therapy.

Methods

A total of 12 pediatric endocrinologists with experience in eHealth, from a wide geographical distribution, participated in a series of online discussions. We summarized the discussions of 3 workshops, conducted during 2020, on the use of eHealth in the management of growth disorders, which were structured to provide insights on existing challenges, opportunities, and solutions for the implementation of eHealth tools across the patient journey, from referral to the end of pediatric therapy.

Results

A total of 815 responses were collected from 2 questionnaire-based activities covering referral and diagnosis of growth disorders, and subsequent growth hormone therapy stages of the patient pathway, relating to physicians, nurses, and patients, parents, or caregivers. We mapped the feedback from those discussions into a framework that we developed as a guide to integration of eHealth tools across the patient journey. Responses focused on improved clinical management, such as growth monitoring and automation of referral for early detection of growth disorders, which could trigger rapid evaluation and diagnosis. Patient support included the use of eHealth for enhanced patient and caregiver communication, better access to educational opportunities, and enhanced medical and psychological support during growth hormone therapy management. Given the potential availability of patient data from connected devices, artificial intelligence can be used to predict adherence and personalize patient support. Providing evidence to demonstrate the value and utility of eHealth tools will ensure that these tools are widely accepted, trusted, and used in clinical practice, but implementation issues (eg, adaptation to specific clinical settings) must be addressed.

Conclusions

The use of eHealth in growth hormone therapy has major potential to improve the management of growth disorders along the patient journey. Combining objective clinical information and patient adherence data is vital in supporting decision-making and the development of new eHealth tools. Involvement of clinicians and patients in the process of integrating such technologies into clinical practice is essential for implementation and developing evidence that eHealth tools can provide value across the patient pathway.

Impact of adherence on growth response during the first 2 years of growth hormone treatment

PURPOSE

Adherence to growth hormone (GH) treatment impacts clinical outcomes. The aim of this study is to assess the impact of adherence to rhGH treatment (2 years) on auxological outcomes.

METHODS

Multicentric, retrospective observational study in rhGH-naïve GHD/SGA children treated with Saizen® during ≥2 years. Growth response was assessed by evaluating the change in height standard deviation score (ΔH SDS) and the index of responsiveness (IoR). Adherence was monitored using EasyPod™ Connect device.

RESULTS

A total of 110 patients (3 Spanish centers) were evaluable (GHD n = 76, SGA n = 34). Adherence was 95.6 and 93.9% (year 1, 2). SGA and GHD children showed an increase of 0.6 cm/year and 1.1 cm/year for each 10% adherence modification. Lower adherence was observed in patients with lower pretreatment height velocity (HV) and in patients whose parents had a lower level of education. A positive correlation between index of responsiveness (IoR) during the first and second years with HV SDS during the second year and between IoR2 and adherence (year 1, 2) was observed. The frequency of patients with HV > 1 SD was higher (p = 0.025) among patients with adherence >90%. The best model to predict the height gain(cm) reaching an adjusted R squared of 0.489 involved percentage of adherence, Tanner stage, pretreatment HV, dose of rhGH, and whether the treatment was initiated before or after puberty.

CONCLUSIONS

Adherence during the first 2 years of response was very high >90% and showed a negative association with age, pretreatment HV and treatment duration and a positive correlation with the level of parent education.

Growth hormone deficit. Does the first year of treatment influence adult height?

INTRODUCTION

Short stature is the most frequent reason for Pediatric Endocrinology consultations and sometimes requires treatment with growth hormone.

OBJECTIVE

The possible correlation of a good response to any early response factor with a better final response was studied, and also whether there was a difference in response to treatment according to the type of deficit.

PATIENTS AND METHODS

This was a longitudinal, retrospective and observational study of 139 patients treated for idiopathic growth hormone deficiency up to adult height. There were good response criteria in the first year of treatment: a) an increase in growth rate≥3cm / year, b) a growth rate≥1 standard deviation (SD), c) an increase in height≥0.5 SD, d) an increase in height≥0.3 SD. Study of the Index of Responsiveness to treatment in the first and second year. Final response variables: adult height with respect to target height, adult height with respect to initial growth prediction and adult height with respect to initial height at the start of treatment. The possible correlation of a good response to any of the early response factors with a better final response to treatment was studied, and also whether there was a difference in the response to treatment according to the type of deficit.

RESULTS

The treatment produced a gain in adult height with respect to genetic height of 0.06±0.7 SD. Patients considered good responders in the first year of treatment presented a better final response (growth rate≥3cm: p=0.000, growth rate≥1 SD: p=0.008, height gain≥0.5 SD: P=0.007, height gain≥0.3 SD: P=0.006), as well as patients with a severe deficit (P=0.04). The index of responsiveness to treatment during the first year was associated with a better final response (r=0.249, P=0.003), with this correlation being maintained in the second year (r=0.294, P=0.01).

CONCLUSIONS

Growth hormone treatment increased height in the genetic target. The percentage of good responders varied depending on the criteria used. The response in the first year of treatment and a severe deficit were determining factors for achieving a good long-term response.

Individual sensitivity to growth hormone replacement in adults

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

Pharmacogenomics applied to recombinant human growth hormone responses in children with short stature

We present current knowledge concerning the pharmacogenomics of growth hormone therapy in children with short stature. We consider the evidence now emerging for the polygenic nature of response to recombinant human growth hormone (r-hGH). These data are related predominantly to the use of transcriptomic data for prediction. The impact of the complex interactions of developmental phenotype over childhood on response to r-hGH are discussed. Finally, the issues that need to be addressed in order to develop a clinical test are described.

Yearly Height Gain Is Dependent on the Truly Received Dose of Growth Hormone and the Duration of Periods of Poor Adherence: Practical Lessons From the French Easypod™ Connect Multicenter Observational Study

OBJECTIVE

To study the impact of the true mean daily dose and the true mean number of injections per week on the yearly height gain in short children treated with recombinant human growth hormone (rhGH).

DESIGN AND METHODS

220 children from the French Easypod™ Connect Observational Study (ECOS) used the Easypod™ electronic device to record rhGH injections. The mean daily rhGH dose (the sum of the doses truly received divided by the number of days) and mean number of injections per week (the number of injections truly performed divided by the number of weeks) were calculated. Linear mixed models were used to study the impact of short (3-month) and long (1-year) variations in rhGH administration on the yearly height change [as a standard deviation score (SDS)], with time on treatment as a covariate. For each patient, several periods of 3 or 12 months were considered and designated as poorly adherence or fully adherence. We studied the impact of each of period on the height change.

RESULTS

At treatment initiation, the mean ± SD age was 9.8 ± 3.7 years (females: 47%, prepubertal: 86%) and the mean height was -2.28 ± 0.92 SDS. The mean treatment duration was 3.2 ± 1.1 years (685.2 patient years). 122 patients were GH-deficient, 79 were small for gestational age, and 19 had Turner syndrome. When treatment was computed over 12-month periods, receiving a mean daily dose <0.03 mg/kg.d was associated with a 20% lower mean yearly height gain SDS when<3 injections/week were received (vs.>5 injections/week), whereas maintaining a mean daily dose >0.03 mg/kg.d with<3 injections/week was not associated with a lower yearly height gain SDS (vs.>5 injections/week). For 3-month periods, changes in the daily rhGH dose or the number of injections per week over such short period did not influence the yearly height gain SDS.

CONCLUSION

The 12-month treatment model showed that when poor adherence leads to a low true daily GH dose, the yearly height gain is low. The 3-month treatment model showed that poor adherence for short periods (<3 months) had no impact on the height SDS.

Is a Two-Year Growth Response to Growth Hormone Treatment a Better Predictor of Poor Adult Height Outcome Than a First-Year Growth Response in Prepubertal Children With Growth Hormone Deficiency?

OBJECTIVE

The first year response to growth hormone (GH) treatment is related to the total height gain in GH treated children, but an individual poor first year response is a weak predictor of a poor total GH effect in GH deficient (GHD) children. We investigated whether an underwhelming growth response after 2 years might be a better predictor of poor adult height (AH) outcome after GH treatment in GHD children.

DESIGN AND METHODS

Height data of GHD children treated with GH for at least 4 consecutive years of which at least two prepubertal and who attained (near) (n)AH were retrieved from the Belgian Register for GH treated children (n = 110, 63% boys). In ROC analyses, the change in height (ΔHt) SDS after the first and second GH treatment years were tested as predictors of poor AH outcome defined as: (1) nAH SDS <-2.0, or (2) nAH SDS minus mid-parental height SDS <-1.3, or (3) total ΔHt SDS <1.0. The cut-offs for ΔHt SDS and its sensitivity at a 95% specificity level to detect poor AH outcome were determined.

RESULTS

Eleven percent of the cohort had a total ΔHt SDS <1.0. ROC curve testing of first and second years ΔHt SDS as a predictor for total ΔHt SDS <1.0 had an AUC >70%. First-year ΔHt SDS <0.41 correctly identified 42% of the patients with poor AH outcome at a 95% specificity level, resulting in respectively 5/12 (4.6%) correctly identified poor final responders and 5/98 (4.5%) misclassified good final responders (ratio 1.0). ΔHt SDS after 2 prepubertal years had a cut-off level of 0.65 and a sensitivity of 50% at a 95% specificity level, resulting in respectively 6/12 (5.5%) correctly identified poor final responders and 5/98 (4.5%) misclassified good final responders (ratio 1.2).

CONCLUSION

In GHD children the growth response after 2 prepubertal years of GH treatment did not meaningfully improve the prediction of poor AH outcome after GH treatment compared to first-year growth response parameters. Therefore, the decision to re-evaluate the diagnosis or adapt the GH dose in case of poor response after 1 year should not be postponed for another year.

Short and Long-Term Effects of Growth Hormone in Children and Adolescents With GH Deficiency

The syndrome of impaired GH secretion (GH deficiency) in childhood and adolescence had been identified at the end of the 19^th century. Its non-acquired variant (naGHD) is, at childhood onset, a rare syndrome of multiple etiologies, predominantly characterized by severe and permanent growth failure culminating in short stature. It is still difficult to diagnose GHD and, in particular, to ascertain impaired GH secretion in comparison to levels in normally-growing children. The debate on what constitutes an optimal diagnostic process continues. Treatment of the GH deficit via replacement with cadaveric pituitary human GH (pit-hGH) had first been demonstrated in 1958, and opened an era of therapeutic possibilities, albeit for a limited number of patients. In 1985, the era of recombinant hGH (r-hGH) began: unlimited supply meant that substantial long-term experience could be gained, with greater focus on efficacy, safety and costs. However, even today, the results of current treatment regimes indicate that there is still a substantial fraction of children who do not achieve adult height within the normal range. Renewed evaluation of height outcomes in childhood-onset naGHD is required for a better understanding of the underlying causes, whereby the role of various factors - diagnostics, treatment modalities, mode of treatment evaluation - during the important phases of child growth - infancy, childhood and puberty - are further explored.

Genetic Screening for Growth Hormone Therapy in Children Small for Gestational Age: So Much to Consider, Still Much to Discover

Children born small for gestational age (SGA), and failing to catch-up growth in their early years, are a heterogeneous group, comprising both known and undefined congenital disorders. Care for these children must encompass specific approaches to ensure optimal growth. The use of recombinant human growth hormone (rhGH) is an established therapy, which improves adult height in a proportion of these children, but not with uniform magnitude and not in all of them. This situation is complicated as the underlying cause of growth failure is often diagnosed during or even after rhGH treatment discontinuation with unknown consequences on adult height and long-term safety. This review focuses on the current evidence supporting potential benefits from early genetic screening in short SGA children. The pivotal role that a Next Generation Sequencing panel might play in helping diagnosis and discriminating good responders to rhGH from poor responders is discussed. Information stemming from genetic screening might allow the tailoring of therapy, as well as improving specific follow-up and management of family expectations, especially for those children with increased long-term risks. Finally, the role of national registries in collecting data from the genetic screening and clinical follow-up is considered.

Adherence and long-term outcomes of therapy in paediatric patients in Greece using the easypod™ electromechanical device for growth hormone treatment: The phase IV multicentre easypod™ connect observational study (ECOS)

BACKGROUND

The easypod™ injection device allows automatic recording and transmission of adherence data from patients receiving recombinant human growth hormone (rhGH [Saizen®]) to treat growth disorders. This analysis aimed to evaluate the adherence of Saizen® administered via easypod™ in a cohort of Greek patients from the easypod™ connect observational study (ECOS).

METHODS

The phase IV, open-label, multicentre, observational, and longitudinal ECOS study (EMR200104-520, NCT01363674) enrolled patients treated for a minimum of 6 months and up to 3 years. The primary endpoint was to assess the mean rate of adherence to treatment at different time points, where good adherence was defined as ≥85%. Change in height, height standard deviation score (SDS), height velocity and height velocity SDS were evaluated after 1 year of treatment as secondary endpoints, together with the impact of adherence on growth outcomes using the Spearman's product moment.

RESULTS

Of the 180 patients enrolled, 86 were included in the analysis. The mean adherence to Saizen®, as recorded via easypod™, was high at each individual time point, and was maintained at 95.5% after 1 year of treatment. Clinically meaningful positive changes were also noted for all of the secondary endpoints (median increase in height = 7.25 cm, height SDS = 0.32, median height velocity = 7.62 cm/year and height velocity SDS = 1.65). However, no significant correlation was noted between adherence and growth outcomes.

CONCLUSIONS

rhGH replacement therapy using Saizen® with easypod™ led to full compliance to the treatment in a representative Greek population from ECOS, and provided additional insights on how the easypod™ device can assist physicians in monitoring adherence and help to optimise linear growth in paediatric patients with growth disorders.

Differential diagnosis between constitutional delay of growth and puberty, idiopathic growth hormone deficiency and congenital hypogonadotropic hypogonadism: a clinical challenge for the pediatric endocrinologist

INTRODUCTION

Differential diagnosis between constitutional delay of growth and puberty (CDGP), partial growth hormone deficiency (pGHD) and congenital hypogonadotropic hypogonadism (cHH) may be difficult. All these conditions usually present with poor growth in pre- or peri-pubertal age and they may recur within one familial setting, constituting a highly variable, but somehow common, spectrum of pubertal delay.

EVIDENCE ACQUISITION

Narrative review of the most relevant English papers published between 1981 and march 2020 using the following search terms "constitutional delay of growth and puberty," "central hypogonadism," "priming," "growth hormone deficiency," "pituitary," "pituitary magnetic resonance imaging," with a special regard to the latest scientific acquisitions.

EVIDENCE SYNTHESIS

CDGP is by far the most prevalent entity in boys and recurs within families. pGHD is a rare, often idiopathic and transient condition, where hypostaturism presents more severely. Specificity of pGHD diagnosis is increased by priming children before growth hormone stimulation test (GHST); pituitary MRI and genetic analysis are recommended to personalize future follow-up. Diagnosing cHH may be obvious when anosmia and eunuchoid proportions concomitate. However, cHH can either overlap with pGHD in forms of multiple pituitary hormone deficiencies (MPHD) or syndromic conditions either with CDGP in family pedigrees, so endocrine workup and genetic investigations are necessary. The use of growth charts, bone age, predictors of adult height, primed GHST and low dose sex steroids (LDSS) treatment are recommended.

CONCLUSIONS

Only a step-by-step diagnostic process based on appropriate endocrine and genetic markers together with LDSS treatment can help achieving the correct diagnosis and optimizing outcomes.

[Aromatase inhibitors combined with growth hormone in treatment of adolescent boys with short stature]

OBJECTIVE

To assess the efficacy and safety of aromatase inhibitors (AIs) combined growth hormone in treatment of adolescent boys with short stature.

METHODS

One hundred and fifty-one short stature pubertal boys with age of 10-14 years and bone age of 13-15 years, who were admitted to the Department of Pediatrics, the First Affiliated Hospital, Zhejiang University School of Medicine, were included in this trial. According to their own or parents' intention, the children were divided into recombinant human growth hormone (rhGH)+AI group ( n=108) and rhGH group ( n=43). All children were injected subcutaneously with rhGH 0.15-0.2 IU·kg ^-1·d ^-1, and those in rhGH+AI group were additionally given 2.5 mg/d letrozole or 1 mg/d anastrozole, orally for 12 months or longer. The children were followed-up every 3 months. During the follow-up visit, the predicted adult height (PAH), sex hormone level, glucose and lipid metabolism, and other indicators were measured, and adverse reactions were monitored.

RESULTS

After intervention, there were significant differences in ΔBA(bone age)/ΔCA(chronological age), ΔHtSDS _BA(height standard deviation score based on bone age)and ΔPAH between rhGH+AI group and the rhGH group( P &lt; 0.05 or P &lt; 0.01). During follow-up, 63.9%of the children in the rhGH+AI group had elevated uric acid and 51.9%had decreased high-density lipoprotein (HDL); 25.9%showed severe acne, excitement, hyperactivity and irritability, 11.1%had knee pain; 4.6%had fracture; 2.8%had mild renal dysfunction; 1.9%had inactivity, drowsiness, memory loss and performance decline; 1.9%showed mild abnormal liver function; 0.9%showed impaired fasting glucose; 0.9%showed granulocytopenia. In the rhGH group, 11.6%of the children presented with knee pain and 2.3%with impaired fasting glucose.

CONCLUSIONS

AI combined with rhGH can delay the growth of BA and effectively improve the PAH of adolescent boys with larger bone age. However, the occurrence of adverse reactions of AI should be closely monitored during treatment.

Diagnosis, Genetics, and Therapy of Short Stature in Children: A Growth Hormone Research Society International Perspective

The Growth Hormone Research Society (GRS) convened a Workshop in March 2019 to evaluate the diagnosis and therapy of short stature in children. Forty-six international experts participated at the invitation of GRS including clinicians, basic scientists, and representatives from regulatory agencies and the pharmaceutical industry. Following plenary presentations addressing the current diagnosis and therapy of short stature in children, breakout groups discussed questions produced in advance by the planning committee and reconvened to share the group reports. A writing team assembled one document that was subsequently discussed and revised by participants. Participants from regulatory agencies and pharmaceutical companies were not part of the writing process. Short stature is the most common reason for referral to the pediatric endocrinologist. History, physical examination, and auxology remain the most important methods for understanding the reasons for the short stature. While some long-standing topics of controversy continue to generate debate, including in whom, and how, to perform and interpret growth hormone stimulation tests, new research areas are changing the clinical landscape, such as the genetics of short stature, selection of patients for genetic testing, and interpretation of genetic tests in the clinical setting. What dose of growth hormone to start, how to adjust the dose, and how to identify and manage a suboptimal response are still topics to debate. Additional areas that are expected to transform the growth field include the development of long-acting growth hormone preparations and other new therapeutics and diagnostics that may increase adult height or aid in the diagnosis of growth hormone deficiency.

Achieving Optimal Short- and Long-term Responses to Paediatric Growth Hormone Therapy

It is over sixty years since the first administration of human growth hormone (GH) to children with GH deficiency, and over thirty years since recombinant human GH has been available for treatment of GH deficiency and a wider range of non-GH deficiency disorders. From a diagnostic perspective, genetic analysis, using single gene or Sanger sequencing and more recently next generation or whole exome sequencing, has brought advances in the diagnosis of specific causes of short stature, which has enabled therapy to be targeted more accurately. Genetic discoveries have ranged from defects of pituitary development and GH action to abnormalities in intracellular mechanisms, paracrine regulation and cartilage matrix formation. The strategy of GH therapy using standard doses has evolved to individualised GH dosing, depending on diagnosis and predictors of growth response. Evidence of efficacy of GH in GH deficiency, Turner syndrome and short children born small for gestational age is reviewed. The importance of critical assessment of growth response is discussed, together with the recognition and management of a poor or unsatisfactory growth response and the organisational issues related to prevention, detection and intervention regarding suboptimal adherence to GH therapy.

TIMING OF GH PEAK IN BOTH GLUCAGON AND CLONIDINE TESTS IS OF MAJOR CLINICAL IMPORTANCE

Objective: To detect a possible correlation between timing of the peak value of growth hormone (GH) during stimulatory tests (STs) and the effectiveness of treatment with recombinant human growth hormone (rhGH) in children with idiopathic GH deficiency (iGHD). Methods: We retrospectively studied 92 patients with iGHD (57 boys; mean age at diagnosis: 9.93 years). Diagnosis was confirmed by 2 different STs, glucagon stimulation test (GST), and clonidine stimulation test (CST). Auxologic parameters were recorded, while observed and predicted (according to KIGS Prediction Model) height velocity during the first year of treatment and the index of responsiveness (IoR) were calculated for the prepubertal children (n = 65). Results: Atypical GST was defined as that with peak GH value at time 0 minutes, 30 minutes, 60 minutes, or 180 minutes, whereas atypical CST was defined as that with peak timing at 0 minutes, 30 minutes, or 120 minutes. Atypical GST was detected in 18 patients (19.57%). IoR was lower in the prepubertal children with atypical GST (-1.81 ± 0.67 versus -1.34 ± 0.85; P = .051). In the CST, the 18 children who had atypical timing, had significantly lower IoR (-1.86 ± 0.66 versus -1.35 ± 0.84; P = .047). When the patients were categorized according to the number of atypical tests, significant differences in the IoR were detected (-2.09 ± 0.68 with 2 atypical STs [n = 6], -1.64 ± 0.61 with 1 atypical ST [n = 16], and -1.29 ± 0.87 with no atypical ST [n = 43], P = .045). Conclusion: The presence of atypical peak GH timing during ST may be a factor that predicts lower growth hormone velocity during the first year of rhGH treatment in prepubertal children with iGHD. Abbreviations: CST = clonidine stimulation test; GH = growth hormone; GHD = growth hormone deficiency; GST = glucagon stimulation test; iGHD = idiopathic growth hormone deficiency; IoR = index of responsiveness; rhGH = recombinant human growth hormone; SDS = standard deviation scores; ST = stimulatory test.

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.

Growth hormone therapy in children; research and practice - A review

Short stature remains the most common reason for referral to a pediatric Endocrinologist and its management remains a challenge. One of the main controversies is the diagnosis of idiopathic short stature and the role of new technologies for genetic investigation of children with inadequate growth. Complexities in management of children with short stature includes selection of who should receive interventions such as recombinant human growth hormone, and how should this agent dose be adjusted during treatment. Should anthropometrical data be the primary determinant or should biochemical and genetic data be used to improve growth response and safety? Furthermore, what is considered a suboptimal response to growth hormone therapy and how should this be managed? Treatment of children with short stature remains a "hot" topic and more data is needed in several areas. These issues are reviewed in this paper.

Criteria for First-Year Growth Response to Growth Hormone Treatment in Prepubertal Children With Growth Hormone Deficiency: Do They Predict Poor Adult Height Outcome?

Objective: Several criteria for first-year growth response (FYGR) to growth hormone (GH) treatment have been proposed. We explored which FYGR criteria predicted best the final height outcome after GH treatment in prepubertal children with GH deficiency (GHD). Design and methods: Height data of 129 GHD children (83 boys) who attained adult height and had been treated with GH for at least 4 consecutive years with at least 1 year before pubertal onset, were retrieved from the Belgian GH Registry. The FYGR parameters were: (1) increase in height (ΔHt) SDS, (2) height velocity (HV) SDS, (3) ΔHV (cm/year), (4) index of responsiveness (IoR) in KIGS prediction models, (5) first-year HV SDS based on the KIGS expected HV curve (HV KIGS SDS), (6) near final adult height (nFAH) prediction after first-year GH treatment. Poor final height outcome (PFHO) criteria were: (1) total ΔHt SDS <1.0, (2) nFAH SDS <-2.0, (3) nFAH minus midparental height SDS <-1.3. ROC curve analyses were performed to define the optimal cut-off for FYGR parameters to predict PFHO. Only ROC curves with an area under the curve (AUC) of more than 70% were further analyzed. Results: Twelve, 22 and 10% of the children had respectively a total ΔHt SDS <1, nFAH SDS <-2, and nFAH minus midparental height SDS <-1.3. The AUC's ranged between 73 and 85%. The highest AUC was found for first-year ΔHt SDS to predict total ΔHt SDS <1, and predicted nFAH SDS to predict nFAH SDS <-2. The currently used FYGR criteria had low specificities and sensitivities to detect PFHO. To obtain a 95% specificity, the cut-off value (and sensitivity) of FYGR parameters were: ΔHt SDS <0.35 (40%), HV SDS <-0.85 (43%), ΔHV <1.3 cm/year (36%), IoR <-1.57 (17%), HV KIGS SDS <-0.83 (40%) to predict total ΔHt SDS <1; predicted nFAH SDS (with GH peak) <-1.94 (25%), predicted nFAH SDS (without GH peak) <-2.02 (25%) to predict nFAH SDS <-2. At these cut-offs, the amount of correctly diagnosed poor final responders equals the amount of false positives. Conclusion: First-year growth response criteria perform poorly as predictors of poor final height outcome after long-term GH treatment in prepubertal GHD children.

Children Born Small for Gestational Age: Differential Diagnosis, Molecular Genetic Evaluation, and Implications

Children born small for gestational age (SGA), defined as a birth weight and/or length below -2 SD score (SDS), comprise a heterogeneous group. The causes of SGA are multifactorial and include maternal lifestyle and obstetric factors, placental dysfunction, and numerous fetal (epi)genetic abnormalities. Short-term consequences of SGA include increased risks of hypothermia, polycythemia, and hypoglycemia. Although most SGA infants show catch-up growth by 2 years of age, ∼10% remain short. Short children born SGA are amenable to GH treatment, which increases their adult height by on average 1.25 SD. Add-on treatment with a gonadotropin-releasing hormone agonist may be considered in early pubertal children with an expected adult height below -2.5 SDS. A small birth size increases the risk of later neurodevelopmental problems and cardiometabolic diseases. GH treatment does not pose an additional risk.

Basal characteristics and first year responses to human growth hormone (GH) vary according to diagnostic criteria in children with non-acquired GH deficiency (naGHD): observations from a single center over a period of five decades

Background Children with non-acquired (na) growth hormone deficiency (GHD) diagnosed over decades in one center may provide perspective insight. Methods naGHD is divided into idiopathic GHD (IGHD), GHD of known cause (cGHD) and GHD neurosecretory dysfunction (NSD); time periods: <1988 (I); 1988-1997 (II); 1998-2007 (III); 2008-2015 (IV). Descriptive analyses were performed at diagnosis and during first year GH treatment. Results Patients (periods, N): I, 87; II, 141; III, 356; IV, 51. In cGHD (all), age, maximum GH, insulin-like growth factor-I (IGF-I), and insulin-like growth factor-binding protein-3 (IGFBP-3) (5.1 years, 3.6 μg/L, -5.3 standard deviation score [SDS], -3.7 SDS) were lower than in IGHD (all) (6.8 years 5.8 μg/L, -2.5 SDS, -1.0 SDS), but not height (-3.1 vs. -3.2 SDS). Characteristics of NSD were similar to that of IGHD. Patients with IGHD - not cGHD - diagnosed during 2008-2015 (IV) were the youngest with most severe GHD (maxGH, IGF-I, IGFBP-3), and first year height velocity (HV) and ∆ IGF-I (10.5 cm/year, 4.0 SDS) but not ∆ height SDS were the highest on recombinant human growth hormone (rhGH) (27 μg/kg/day). Conclusions Although during 1988-2007 patient characteristics were similar, the recently (>2008) stipulated more stringent diagnostic criteria - HV before testing, sex steroid priming, lower GH cut-off - have restricted diagnoses to more severe cases as they were observed before the rhGH era.

Effect of adherence to growth hormone treatment on 0-2 year catch-up growth in children with growth hormone deficiency

Background

Quantifying the association between adherence and the growth response to growth hormone (GH) treatment is hampered by suboptimal methods of measuring adherence, confounders associated with the growth response, and restriction of the outcome parameters to yearly growth velocities.

Aim

To investigate the effect of adherence on the two-year growth response to GH treatment in prepubertal children with idiopathic isolated growth hormone deficiency (GHD) participating in the easypod connect observational study (ECOS), a 5-year, Phase IV open-label study to continuously assess real-world adherence via the easypod electronic drug-delivery device.

Patients and methods

Outcome measures were change in height standard deviation score (ΔHSDS), index of responsiveness (IoR), and parameters of two catch-up growth (CUG) curve functions (monomolecular growth curve and second degree polynomial) with adj-HSDS (HSDS minus Target height (TH) SDS) as dependent variable. Inclusion criteria were GHD, naïve to GH treatment, known TH, age <10y in girls and <12y in boys, ≥3 measurements, HSDS <-2 at start, complete data on growth and adherence in the first and second year. Linear regression analyses were performed to test the association between adherence (continuous and high vs. low) and the outcome measures, also adjusted for potential clinical confounders (age at start, adj-HSDS at start, birth weight SDS, gestational age (<37 weeks vs ≥37 weeks), GH dose, GH max (n = 58)). The formula of IoR already adjusts for confounders.

Results

In total, 95 patients complied with the inclusion criteria. The strongest associations were found between high adherence in the second year (≥91% as cut-off value) and IoR 2y (+0.62), and average adherence and high adherence (≥78%) in the first two years and ΔHSDS 0-2y (+0.11 SD per 1 injection/week, and +0.34 SD for high vs. low adherence).

Conclusion

Suboptimal adherence negatively affected the growth response in the first two years of GH treatment.

Poor growth response during the first year of growth hormone treatment in short prepubertal children with growth hormone deficiency and born small for gestational age: a comparison of different criteria

Background

There is no consensus on the definition of poor growth response after the first year of growth hormone (GH) treatment. We determined the proportion of poor responders identified by different criteria in children with GH deficiency (GHD) and born small for gestational age (SGA). The second aim was to analyze the IGF-1 response in poor growth responders.

Methods

First-year height data of 171 SGA and 122 GHD children who remained prepubertal during the first GH treatment year were retrieved from the BESPEED database and analyzed. Criteria for poor first-year response/responsiveness were: change in height (∆Ht) SDS<0.3 or<0.5, height velocity (HV) SDS<0.5 or <1 based on the population reference, HV SDS<- 1 based on the KIGS expected HV curve (HV Ranke SDS), studentized residual (SR) <- 1 in the KIGS first-year prediction model.

Results

∆Ht SDS<0.5 gave the highest percentage poor responders (37% SGA, 26% GHD). Although % poor responders were comparable for ∆Ht SDS<0.3, HV SDS<+ 0.5, HV SDS<+ 1, SR<- 1, and HV Ranke SDS<- 1, these criteria did not always identify the same patients as poor responders. Among the poor growth responders 24% SGA and 14% GHD patients had an IGF-1 increase < 40%.

Conclusions

The different response criteria yield high but comparable percentages poor responders, but identify different patients. This study does not provide evidence that one criterion is better than another. A limited IGF-1 generation is not the major reason for a poor growth response in the first year of GH treatment in SGA and GHD children.

Trial registration

Retrospectively registered.

Long-term response to recombinant human growth hormone treatment: a new predictive mathematical method

INTRODUCTION

Recombinant GH has been offered to GH-deficient (GHD) subjects for more than 30 years, in order to improve height and growth velocity in children and to enhance metabolic effects in adults.

AIM

The aim of our work is to describe the long-term effect of rhGH treatment in GHD pediatric patients, suggesting a growth prediction model.

MATERIAL AND METHODS

A homogeneous database is defined for diagnosis and treatment modalities, based on GHD patients afferent to Hospital Regina Margherita in Turin (Italy). In this study, 232 GHD patients are selected (204 idiopathic GHD and 28 organic GHD). Each measure is shown in terms of mean with relative standard deviations (SD) and 95% confidence interval (95% CI). To estimate the final height of each patient on the basis of few measures, a mathematical growth prediction model [based on Gompertzian function and a mixed method based on the radial basis functions (RBFs) and the particle swarm optimization (PSO) models] was performed.

RESULTS

The results seem to highlight the benefits of an early start of treatment, further confirming what is suggested by the literature. Generally, the RBF-PSO method shows a good reliability in the prediction of the final height. Indeed, RMSE is always lower than 4, i.e., in average the forecast will differ at most of 4 cm to the real value.

CONCLUSIONS

In conclusion, the large and accurate database of Italian GHD patients allowed us to assess the rhGH treatment efficacy and compare the results with those obtained in other Countries. Moreover, we proposed and validated a new mathematical model forecasting the expected final height after therapy which was validated on our cohort.

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.

Growth hormone - past, present and future

Growth hormone (GH) research and its clinical application for the treatment of growth disorders span more than a century. During the first half of the 20th century, clinical observations and anatomical and biochemical studies formed the basis of the understanding of the structure of GH and its various metabolic effects in animals. The following period (1958-1985), during which pituitary-derived human GH was used, generated a wealth of information on the regulation and physiological role of GH - in conjunction with insulin-like growth factors (IGFs) - and its use in children with GH deficiency (GHD). The following era (1985 to present) of molecular genetics, recombinant technology and the generation of genetically modified biological systems has expanded our understanding of the regulation and role of the GH-IGF axis. Today, recombinant human GH is used for the treatment of GHD and various conditions of non-GHD short stature and catabolic states; however, safety concerns still accompany this therapeutic approach. In the future, new therapeutics based on various components of the GH-IGF axis might be developed to further improve the treatment of such disorders. In this Review, we describe the history of GH research and clinical use with a particular focus on disorders in childhood.

Growth response to growth hormone treatment in patients with SHOX deficiency can be predicted by the Cologne prediction model

Background Growth hormone (GH) treatment in children with short stature homeobox-containing gene (SHOX) deficiency is recognized to increase height velocity (HV) and adult height. Prediction of growth response continues to be a challenge. A comparatively accurate method is the Cologne prediction model developed in children with GH deficiency. The aim was to investigate whether this model also applies to patients with SHOX deficiency. Methods Included were 48 patients with SHOX deficiency confirmed by DNA analysis and treated with 0.05 mg/kg/day of somatropin. Prediction by the Cologne model uses the following variables: relative bone age (BA) retardation, baseline insulin-like growth factor-I (IGF-I), urinary deoxypyridinoline (DPD) cross-links at 4 weeks and HV at 3 months. Results HV and height standard deviation scores (SDS) increased significantly during the first year of treatment. Predicted and observed HV (cm/year) showed a Pearson correlation coefficient of 0.50 (p<0.001; root-mean-square error=1.63) and for first-year change in height SDS a Pearson correlation coefficient of 0.751 (p<0.001; root-mean-square error=0.32). Poor response could be adequately predicted using SDS change, with sensitivity and specificity both above 70% for certain thresholds.

CONCLUSIONS

The results demonstrate that the Cologne model can be used to predict growth response in patients with SHOX deficiency with reasonable precision in the first treatment year, comparable to prediction in patients with GH deficiency.