A case report: Alport syndrome and growth hormone deficiency associated with a new COL4A4 mutation.

Background: Alport syndrome (AS) is a rare progressive hereditary kidney disease that is clinically principally associated with hematuria, proteinuria, and progressive renal dysfunction. This condition not only impairs renal function but also potentially affects auditory and ocular health, significantly impacting the patient's quality of life. Case Description: This article reports a young girl with AS, combined with dwarfism attributable to growth hormone (GH) deficiency, diagnosed at Wenzhou People's Hospital in 2019. The clinical data and diagnostic steps were retrospectively analyzed. Genetic testing showed that she carried a new mutation in the COL4A4 gene, c.2317_2318delAG (p.R773Gfs*14), classified as "pathogenic" under the criteria of the American College of Medical Genetics and Genomics (ACMG), confirming her AS diagnosis. Significantly, the patient's height was more than two standard deviations (SDs) below the average for children of her race, sex, and age. The peak GH level post-stimulation was below 5 ng/mL, coupled with a growth rate of less than 5 cm/year, leading to the diagnosis of GH deficiency. Consequently, recombinant human GH (rhGH) therapy was initiated. Conclusions: After a year of rhGH treatment, we observed a notable increase in her height, without any adverse effects like elevated intracranial pressure, hypothyroidism, or worsening kidney function.

Genotype and phenotype in patients with ACAN gene variants: Three cases and literature review.

OBJECTIVE: To characterize the phenotype spectrum, diagnosis, and response to growth-promoting therapy in patients with ACAN variants causing familial short stature. METHODS: Three families with ACAN variants causing short stature were reported. Similar cases in the literature were summarized, and the genotype and phenotype were analyzed. RESULTS: Three novel heterozygous variants, c.757+1G>A, (splicing), c.6229delG, p.(Asp2078Tfs*1), and c.6679C>T, p.(Gln2227*) in the ACAN gene were identified. A total of 314 individuals with heterozygous variants from 105 families and 8 individuals with homozygous variants from 4 families were confirmed to have ACAN variants from literature and our 3 cases. Including our 3 cases, the variants reported comprised 33 frameshift, 39 missense, 23 nonsense, 5 splicing, 4 deletion, and 1 translocation variants. Variation points are scattered throughout the gene, while exons 12, 15, and 10 were most common (25/105, 11/105, and 10/105, respectively). Some identical variants existing in different families could be hot variants, c.532A>T, p.(Asn178Tyr), c.1411C>T, p.(Gln471*), c.1608C>A, p.(Tyr536*), c.2026+1G>A, (splicing), and c.7276G>T, p.(Glu2426*). Short stature, early-onset osteoarthritis, brachydactyly, midfacial hypoplasia, and early growth cessation were the common phenotypic features. The 48 children who received rhGH (and GnRHa) treatment had a significant height improvement compared with before (-2.18 ± 1.06 SD vs. -2.69 ± 0.95 SD, p < 0.001). The heights of children who received rhGH (and GnRHa) treatment were significantly improved compared with those of untreated adults (-2.20 ± 1.10 SD vs. -3.24 ± 1.14 SD, p < 0.001). CONCLUSION: Our study achieves a new understanding of the phenotypic spectrum, diagnosis, and management of individuals with ACAN variants. No clear genotype-phenotype relationship of patients with ACAN variants was found. Gene sequencing is necessary to diagnose ACAN variants that cause short stature. In general, appropriate rhGH and/or GnRHa therapy can improve the adult height of affected pediatric patients caused by ACAN variants.

GH therapy in children with juvenile idiopathic arthritis: a four-decade review.

Chronic inflammatory conditions, such as juvenile idiopathic arthritis, are associated with growth failure. Growth failure appears to be correlated with both the effects of inflammation and negative effects of glucocorticoids (used as therapeutic option) on the growth hormone axis and locally on the growth plate and bone metabolism. In the last decade, the introduction of biologics has changed the disease course regarding consequences and outcomes. Anyway in some cases, treatment with biologics has failed in restoring normal growth in patients with juvenile idiopathic arthritis; in contrast, several studies have reported improved height velocity and growth rate in patients with juvenile idiopathic arthritis treated with growth hormone. This study aimed to evaluate the impact of growth hormone treatment on the growth and pubertal development in juvenile idiopathic arthritis patients through a narrative review of the literature over the last four decades.

Letrozole combined with rhGH treatment increases the adult height of short pubertal boys.

OBJECTIVES: This study was performed to investigate the effectiveness of the combination of letrozole and recombinant human growth hormone (rhGH) to improve the predicted adult height (PAH) and final adult height (FAH) of Chinese short pubertal boys. METHODS: In total, 171 Chinese short pubertal boys were recruited for this study. 96 of them received letrozole (2.5 mg/d) combined with rhGH (33.3-66.6 µg/kg.d), and the others received rhGH alone. Follow-up visits were conducted at 1, 3, 6, 9, and 12 months or regularly after the first treatment. During each visit, plasma samples were collected for clinical tests and biomedical analyses, all of which were performed according to standard protocols. This study was registered at www.chictr.org.cn under ID number ChiCTR1900026142. RESULTS: After receiving treatment for at least 3 months, 68 boys (91 %) in the rhGH therapy group and 90 (94 %) in the letrozole combined with rhGH (letrozole+rhGH) therapy group achieved an increase in PAH, with the latter treatment leading to a more effective slowing of bone age (BA) advancement. Moreover, the increased PAH showed a significant positive correlation with treatment time in both groups, and letrozole+rhGH increased the PAH to a greater degree than rhGH alone (p=0.0023). And letrozole+rhGH not only slowed the increase in BA more efficiently than rhGH therapy alone (p=0.0025), but also achieved a higher FAH (p=0.0078). CONCLUSIONS: Letrozole combined with rhGH treatment is a promising therapy to increase the PAH and FAH of Chinese short pubertal boys.

A Case of Floating-Harbor Syndrome with "Growth and Language Development Delay" as Its Clinical Manifestation.

Background: Floating-Harbor syndrome (FHS) is a rare autosomal dominant inherited disease characterized primarily by short stature, delayed language development, and typical facial features. There are currently few case reports, diagnoses and treatments for these syndromes at home and abroad. Case Description: This study reports a case of a boy with "growth and language development delay" as the predominant clinical manifestation. FHS was clinically diagnosed based on his growth hormone (GH) deficiency, significant bone age delay, left testicular hydrocele, and the whole exon gene in peripheral blood, which indicated heterozygous mutation of SRCAP gene. Following the treatment with recombinant human GH (rhGH), the child exhibited height increase benefits, and his articulation improved after language therapy. Conclusion: Genetic testing facilitates early detection, diagnosis, and treatment of the FHS. Additionally, treatment with rhGH effectively increases the height of these children, and language rehabilitation is especially important for their language development.

PLGA and PEG based porous microparticles as vehicles for pulmonary somatropin delivery.

Breakthrough advances in protein therapeutics and sustained release systems continue to fuel innovation in novel, non-invasive polymeric platforms for delivery of biologicals. Despite the bench potential and proof-of-concept work, market analysis still shows biologicals to be predominantly injections. Characterized by insufficient secretion of growth hormone by the pituitary gland, growth hormone deficiency (GHD) is a rare disorder. Currently, chronic somatropin (r-hGH) replacement therapy is only available as subcutaneous injections administered several times a week. We aim to prepare large, porous, biodegradable and aerodynamically light microparticles as tunable carriers for pulmonary r-hGH delivery. We developed a range of microparticles using PLGA 5050 1Awith sizes between 5 µm and 13 µm, densities lower than 0.4 g/cc and aerodynamic diameters lower than 6 µm. Polyethylene glycol's multitude of advantages - plasticizing PLGA, improving the biocompatibility of the system and preventing protein burst release - have been extensively studied, making it our excipient (pore-former) of choice. Drug loading was characterized at pH 4.0 (acidic), 5.3 (pI) and pH 7.2 (neutral) and was a result of an interplay of electrostatic and hydrophobic interactions between the polymer and somatropin. Considering the physicochemical interactions, we observed some pH dependent protein unfolding characterized by reduction in intrinsic fluorescence of the Tryptophan 86 residue at 331 nm. The secondary ⍺-helix structure characterized by 2 negative minima at 209 nm and 222 nm in the circular dichroism spectra, was intact at all pH values. R-hGH was released over a period of seven days, and the release profile was a function of the microparticle porosity.

Novel pathogenic NPR2 variants in short stature patients and the therapeutic response to rhGH.

OBJECTIVE: Heterozygous loss-of-function variants in the NPR2 gene cause short stature with nonspecific skeletal abnormalities and account for about 2 ~ 6% of idiopathic short stature. This study aimed to analyze and identify pathogenic variants in the NPR2 gene and explore the therapeutic response to recombinant growth hormone (rhGH). METHODS: NPR2 was sequenced in three Chinese Han patients with short stature via exome sequencing. In vitro functional experiments, homology modeling and molecular docking analysis of variants were performed to examine putative protein changes and the pathogenicity of the variants. RESULT: Three patients received rhGH therapy for two years, and two NPR2 heterozygous variants were identified in three unrelated cases: c.1579 C > T,p.Leu527Phe in patient 1 and c.2842dupC,p.His948Profs*5 in patient 2. Subsequently, a small gene model was constructed, and transcriptional analysis of the synonymous variant (c.2643G > A) was performed in patient 3, which revealed the deletion of exon 17 and the premature formation of a stop codon (p.His840Gln*). Functional studies showed that both NPR2 variants, His948Profs*5 and His840Gln*, failed to produce cGMP in the homozygous state. Furthermore, the Leu527Phe variant of NPR2 was almost unresponsive to the stimulatory effect of ATP on CNP-dependent guanylyl cyclase activity. This loss of response to ATP has not been previously reported. The average age of patients at the start of treatment was 6.5 ± 1.8 years old, and their height increased by 1.59 ± 0.1 standard deviation score after 2 years of treatment. CONCLUSION: In this report, two novel variants in NPR2 gene were described. Our findings broaden the genotypic spectrum of NPR2 variants in individuals with short stature and provid insights into the efficacy of rhGH in these patients.

Real-life long-term efficacy and safety of recombinant human growth hormone therapy in children with short stature homeobox-containing deficiency.

Objective: This Italian survey aims to evaluate real-life long-term efficacy and safety of recombinant human growth hormone (rhGH) therapy in children with short stature homeobox-containing gene deficiency disorders (SHOX-D) and to identify potential predictive factors influencing response to rhGH therapy. Design and methods: This is a national retrospective observational study collecting anamnestic, anthropometric, clinical, instrumental and therapeutic data in children and adolescents with a genetic confirmation of SHOX-D treated on rhGH. Data were collected at the beginning of rhGH therapy (T0), yearly during the first 4 years of rhGH therapy (T1, T2, T3 and T4) and at near-final height (nFH) (T5), when available. Results: One hundred and seventeen SHOX-D children started rhGH therapy (initial dose 0.23 ± 0.04 mg/kg/week) at a mean age of 8.67 ± 3.33 years (74% prepubertal), 99 completed the first year of treatment and 46 reached nFH. During rhGH therapy, growth velocity (GV), standard deviation score (SDS) and height (H) SDS improved significantly. Mean H SDS gain from T0 was +1.14 ± 0.58 at T4 and +0.80 ± 0.98 at T5. Both patients carrying mutations involving intragenic SHOX region (group A) and ones with regulatory region defects (group B) experienced a similar beneficial therapeutic effect. The multiple regression analysis identified the age at the start of rhGH treatment (ß = -0.31, P = 0.030) and the GV during the first year of rhGH treatment (ß = 0.45, P = 0.008) as main independent predictor factors of height gain. During rhGH therapy, no adverse event of concern was reported. Conclusions: Our data confirm the efficacy and safety of rhGH therapy in SHOX-D children, regardless the wide variety of genotype. Significance Statement: Among children with idiopathic short stature, the prevalence of SHOX-D is near to 1/1000-2000 (1.1-15%) with a wide phenotypic spectrum. Current guidelines support rhGH therapy in SHOX-D children, but long-term data are still few. Our real-life data confirm the efficacy and safety of rhGH therapy in SHOX-D children, regardless of the wide variety of genotypes. Moreover, rhGH therapy seems to blunt the SHOX-D phenotype. The response to rhGH in the first year of treatment and the age when rhGH was started significantly impact the height gain.

Case Report: Recombinant human growth hormone therapy in a patient with spondyloepiphyseal dysplasia, Kondo-Fu type.

Background: Variants in membrane-bound transcription factor peptidase, site 1 (MBTPS1) gene, can result in clinically rare spondyloepiphyseal dysplasia of Kondo-fu type (OMIM #618392, SEDKF), Silver-Russell syndrome, and CAOP (cataract, alopecia, oral mucosal disorder, and psoriasis-like) syndrome. Case presentation: A 6-year-old Chinese male child diagnosed with SEDKF underwent 3 years of growth hormone therapy. A genetic examination revealed two new nonsense variants in the MBTPS1 gene on chromosome 16q23-q24 with compound heterozygotes c.1589(exon12)A > G and c.163(exon2)G > A. Conclusion: The MBTPS1 gene c.1589(exon12)A > G and c.163(exon2)G > A on chromosome 16q23-q24 is associated with SEDKF. Growth hormone therapy can repair growth retardation in patients with spondyloepiphyseal dysplasia, Kondo-Fu type; however, more evidence of such patient cases is required to support this hypothesis.

CTCF variant begets to short stature by down-regulation of IGF1.

Pathogenic variants in the transcription factor CCCTC-binding factor (CTCF) are associated with mental retardation, autosomal dominant 21 (MRD21, MIM#615502). Current studies supported the strong relationship between CTCF variants and growth, yet the mechanism of CTCF mutation leading to short stature is not known. Clinical information, treatment regimens, and follow-up outcomes of a patient with MRD21 were collected. The possible pathogenic mechanisms of CTCF variants leading to short stature were investigated using immortalized lymphocyte cell lines (LCLs), HEK-293T, and immortalized normal human liver cell lines (LO2). This patient received long-term treatment with recombinant human growth hormone (rhGH) which resulted in an increased height of 1.0 SDS. She had low serum insulin-like growth factor 1 (IGF1) before the treatment and the IGF1 level was not significantly increased during the treatment (-1.38 ± 0.61 SDS). The finding suggested that the CTCF R567W variant could have impaired IGF1 production pathway. We further demonstrated that the mutant CTCF had a reduced ability to bind to the promoter region of IGF1, consequently significantly reducing the transcriptional activation and expression of IGF1. Our novel results demonstrated a direct positive regulation of CTCF on the transcription of the IGF1 promoter. The impaired IGF1 expression due to CTCF mutation may explain the substandard effect of rhGH treatment on MRD21 patients. This study provided novel insights into the molecular basis of CTCF-associated disorder.

Application of Design of Experiment in development of purification process of recombinant human growth hormone-Fc fusion protein / 中国生物制品学杂志

@#ObjectiveTo optimize the condition for anion exchange chromatography in purification process of recombinant human growth hormone-Fc(rhGH-Fc)fusion protein by Design of Experiment(DOE)so as to decrease the content of host cell protein(HCP)in bulk of protein.MethodsA complete factorial experimental design with four factors at two levels was established by the DOE in Minitab 19 software.The condition(flow rate,sample load,pH value of buffer and salt concentration of eluent)for anion exchange chromatography in purification process of rhGH-Fc was optimized by DOE to find out the operating space.ResultsThe experimental results were predicted accurately by the established DOE model.The sample load,pH value of buffer,salt concentration of eluent as well as the interaction of pH value of buffer and salt concentration of eluent showed significant influence on the HCP content in the harvest.The optimal sample load,flow rate as well as pH value and salt concentration of eluent were 15 mg/mL,120 cm/h,7.0 ～ 8.0 and 0.1 mol/L respectively.The HCP contents in eluents under the optimal condition were less than 400 ng/mg,which met the requirements for verification within the range of results in determined operating space.ConclusionThe condition for removal of HCP by anion exchange chromatography was successfully optimized by DOE,which provided a reference for further application of DOE in the biopharmaceutical field.

Development and verification of whole-column imaging capillary isoelectric focusing electrophoresis analysis method for charge heterogeneity of human growth hormone Fc fusion protein / 中国生物制品学杂志

@#Objective To develop and verify a whole-column image capillary isoelectric focusing(iCIEF) electrophoresis method to analyze the charge heterogeneity of recombinant human growth hormone Fc fusion protein(Fc-rhGH).Methods The iCIEF analysis method of Fc-rhGH was developed by optimizing the target protein concentration,cosolvent(urea)concentration and focusing time.The target protein was simultaneously analyzed by this method and traditional flat plate isoelectric focusing(IEF) electrophoresis,and the results were compared;The specificity,accuracy,precision,limit of quantitation(LOQ) and durability of the developed method were verified.Results The optimized method was using the mixed solution of 8 mol/L urea,0.35% methyl cellulose(MC),4% amphoteric electrolyte and 0.5% isoelectric point marker as the sample buffer,and the focusing condition was 1 500 V 1 min,3 000 V 5.5 min.IEF was not suitable for analyzing the charge heterogeneity of Fc-rhGH solution.Using the optimized iCIEF for analysis,the target protein was significantly different from the unrelated protein,and the baseline of blank reagent was stable;The recovery rate of accuracy verification was within 90%～110%,and the linear range was 0.25～0.75 mg/mL(50%～150% of the target loading volume);The RSD of each isomer pI in the repeatability verification was less than 0.3%,and the RSD of peak area percentage was less than 5%;The LOQ was 0.04 mg/ml.The sample storage time durability,amphoteric electrolyte pharmalyte 3-10 durability and MC durability of this method were good.Using this method to analyze the charge heterogeneity of Fc-rhGH physicochemical reference substance,eight charge heterogeneities of the reference substance were effectively separated,and the pI ranged from 5.9 to 6.4.Conclusion The developed iCIEF method had good specificity,accuracy,precision and durability,and was more suitable for efficient analysis of charge heterogeneity of Fc-rhGH than traditional flat plate IEF,which was of great significance for the quality control of Fc-rhGH and other Fc fusion proteins.

Optimization and verification of size exclusion chromatography-high performance liquid chromatography for determination of recombinant human growth hormone-Fc immunofusion protein polymer / 中国生物制品学杂志

@#Objective To optimize and verify the size exclusion chromatography-high performance liquid chromatography(SEC-HPLC) method for the determination of recombinant human growth hormone(rhGH)-Fc immunofusion protein polymer.Methods The multimer content of rhGH-Fc immunofusion protein was detected by SEC-HPLC.The detection conditions(salt concentration,mobile phase pH,flow rate,column temperature and column model) were optimized to observe the separation effect of the target proteins and polymers.The system suitability,specificity,linearity and range,precision,accuracy and limit of quantification of the method were verified.Results The optimized method was to use TSK-gel G2000SW_(x1)column(5 μm,7.8 mm × 300 mm),mobile phase of 50 mmol/L phosphate buffer(pH 6.80),detection wavelength of280 nm,injection volume of 100 μL,flow rate of 0.6 mL/min and column temperature of 45 ℃.The resolution of rhGHFc immunofusion protein and polymer,the theoretical plate number and the tailing factor all met the requirements;the peak time of rhGH-Fc immunofusion protein was the same as that of the control,while the peak time of GH national standard was different from that of the control,and the protein buffer showed no peak;the concentration of rhGH-Fc immunofusion protein was in the range of 0.307～1.842 mg/mL with good linear correlation between the peak area integral value and the injection volume(R~2=0.999 4);the RSD of peak area and purity in repeatability verification were 0.7% and 0.1%,respectively;the RSD of intermediate precision verification was 0.8%;the average recovery rate of accuracy verification was 99.1% with the RSD of 1.9%;the limit of quantification was 6 μg/mL.Conclusion The optimized SEC-HPLC method was used to detect the content of polymer in rhGH-Fc immunofusion protein with improved accuracy,and the column efficiency and separation were in accordance with the relevant requirements of Chinese Pharmacopoeia(Volume Ⅳ,2020edition),which could be used for the detection of polymer content in samples.

Development and validation of a LC-MS/MS method for quantitation of recombinant human growth hormone in rat plasma and application to a pharmacokinetic study.

Recombinant human growth hormone (rhGH) is a peptide comprising 191 amino acids, that is mainly used to promote the growth of children and plays an important antiaging role. In the present study, a simple and sensitive quantitation method for rhGH in rat plasma was established by LCMS/MS. After simple and rapid enzymatic digestion of the plasma sample, two suitable surrogate peptides (LFDNAMLR and FPTIPLSR) were selected for quantitative analysis. The results showed good linearity over calibration range 10-2000 ng/mL. The quality control (QC) accuracy ranged from -13.8 to 14.3%, and the accuracy of the lower limit of quantification (LLOQ) ranged from -12.9 to 19.0%. The intra-day and inter-day precision ranges for all QCs were 1.7-13.6% and 4.0-7.0%, respectively. The method was successfully applied to intravenous and subcutaneous pharmacokinetic studies in rats. In comparison with previously published methods, our method features simple sample preparation combined with a short sample processing time (3.5 h), wide linear range (10-2000 ng/mL), small plasma volume (35 µL), and LLOQ (10 ng/mL).

Optimization of glycosylation type of recombinant human growth hormone-Fc fusion protein expressed in CHO cells / 中国生物制品学杂志

@#Objective To optimize the expression of recombinant human growth hormone-Fc(rhGH-Fc)fusion protein in CHO cells in order to obtain better glycosylation ratio and lower content of highmannose.Methods CHO cells expressing rhGH-Fc were cultured in a 7 L bioreactor.The glycosylation modifications of rhGH-Fc were adjusted by improving the composition of feeding media(using three commercial media:Gly-1:EX-CELL Glycosylation Adjust,Gly-2:SHEFF-CHO PLUS PG ACF and Gly-3:EfficientFeed C + AGT Supplement & GlycanTune C + Total Feed),and the glycosylation type and proportion of the target proteins were analyzed by mass spectrometry.Results The G0F(main glycosylation types:G0,G1 and G2;F:fucose)of Gly-1,Gly-2 and Gly-3 were 32.89%,58.66% and 33.28%,the G1F were 31.39%,18.03%and 34.90%,and the G2F were 31.39%,18.03% and 34.90%,respectively.Gly-1 and Gly-3 made the target protein contain less G0F while more G2F;Gly-3 feeding scheme-showed less high mannose modification than the other two schemes.Conclusion Gly-1 medium changed the glycosylation modification from G0F to G1F and G2F,while Gly-2 medium changed that from G2F and G1F to G0F.However,Gly-3 medium changed the glycosylation modification from G0F to G1F and G2F,and the contentof high mannose was less than 5%,which may have a better effect on modifying glycosylation type and proportion of the target protein.

Changes, limitations, and prospects of adult height in GH treatment for Japanese GHD patients.

For the treatment of pituitary dwarfism (called pituitary short stature in 1987 and renamed as growth hormone deficiency [GHD] in 1993), pituitary-derived human growth hormone (phGH) was approved in 1975, and recombinant hGH (rhGH) was approved in 1988. Adult height in patients with isolated GH deficiency (IGHD) improved by 2000. However, this improvement was mainly due to the increase in height SDS at treatment initiation. Although the mean adult height in patients with idiopathic GHD has been reported to be approximately -1.0 SD or higher in Europe and the United States, the mean adult height of patients with idiopathic GHD in Japan has not improved as much as that in Europe and the United States after 2000. The possible reasons were: low therapeutic doses than those in Europe and the United States; changes in background factors, such as reduction in severe GHD; differences in response to GH between Caucasians and Japanese; and, no increase in height at puberty onset because delayed puberty was normalized by GH treatment. In the future, long-acting GH is expected to improve adult height in GHD patients in Japan.

Population pharmacokinetic/pharmacodynamic analysis of PEG-rhGH enhances confidence in exploring dosing schemes with longer intervals.

BACKGROUND AND OBJECTIVES: PEG-rhGH (Jintrolong®, 0.2 mg/kg/week) is approved in China for the treatment of growth hormone deficiency (GHD) in children. Although 0.2 mg/kg/2 weeks PEG-rhGH failed the non-inferiority threshold of 20% compared with 0.2 mg/kg/week PEG-rhGH, it notably increases serum IGF-1 levels and height velocity in a phase IV trial. In the absence of investigation on the relationship between pharmacokinetics and pharmacodynamics, this analysis aimed to build a population pharmacokinetic/pharmacodynamic (PopPK/PD) model to characterize the relationship between serum PEG-rhGH concentration and serum insulin-like growth factor-1 (IGF-1) levels after subcutaneously administration of PEG-rhGH and to explore the possibility of flexible dosing schemes and improve the clinical monitor practice of IGF-1 levels. METHODS: A total of 41 subjects were included for the PopPK analysis, consisting of 30 healthy adults (single dose of 0.1-0.4 mg/kg) and 11 GHD children (multiple doses of 0.2 mg/kg/2 weeks for 26 consecutive weeks). Only GHD children were included for the PopPK/PD analysis. The time courses of serum PEG-rhGH concentrations in healthy adults and GHD children and those of serum IGF-1 levels stimulated by serum PEG-rhGH were well developed with non-linear mixed-effects modeling. RESULTS: Serum PEG-rhGH pharmacokinetics after subcutaneous administration were adequately described by a one-compartment model with a zero-order input into the absorption compartment followed by first-order absorption dictating absorption into the central compartment, with a dual elimination process consisting of a capacity limited process and a non-capacity limited process. Body weight was a significant covariate. The drug effects on IGF-1 levels were adequately described by a turnover model with saturable effect relationship. IGF-1 responses at the various dosing scheme scenarios were simulated, and illustrated that dosing schemes with intervals longer than the approved one week could be promising, which may provide comparable peaks and average IGF-1 levels and IGF-1 SDS to dosing schemes that have been clinically proven to be tolerated and effective. An accurate prediction of the time course of the effect of various dosing schemes may assist the clinical monitoring practice. CONCLUSIONS: This pharmacokinetic/pharmacodynamic analysis suggested that longer intervals or higher dosing strengths (e.g., 0.3 mg/kg/10 days) in children with GHD are promising compared with the approved dosing scheme (0.2 mg/kg/week). Our simulation may assist the clinical monitoring of the PEG-rhGH therapy.

Recombinant Human Growth Hormone Therapy for Childhood Trichorhinophalangeal Syndrome Type I: A Case Report.

Trichorhinophalangeal syndrome type I (TRPS I; MIM 190350) is a rare autosomal dominant disorder of congenital malformations due to variants of the gene TRPS1. We reported on an 11-year-old Chinese boy with TRPS I. He had typical clinical findings, including sparse hair, a bulbous nose, a long philtrum, a thin upper lip, and skeletal abnormalities including cone-shaped epiphyses, shortening of the phalanges, and short stature. Trio whole exome sequencing identified a likely pathogenic heterozygous variant c.1957C > T (p.Q653*) in exon 4 of TRPS1, which has not been previously reported. He had been treated with rhGH therapy at a dose of 0.34 mg/(kg/week) at age 11, and a follow-up was conducted for one year. The rhGH therapy led to an increase in growth with a mean growth velocity of 1.12 cm/month (+1.1 SDS/year), and insulin-like growth factor 1 (IGF-1) concentration increased within normal range in our case. Moreover, we summarize 12 cases with TRPS I, including TRPS1 gene variants, growth hormone (GH) axis evaluation, IGF-1 concentration, and treatment in each analyzed case. Eight cases with TRPS I show a good response to rhGH therapy, and five of them have elevated IGF-1. Classic GH deficiency is not common among patients with TRPS I. The presence or absence of GH deficiency is not an absolute criterion for determining whether rhGH therapy should be used in TRPS I. It proves that rhGH therapy improves height outcomes before puberty in TRPS I in the short term. Effects on final adult height will need a longer follow-up and more adult-height data. The rise in IGF-1 could correlate with an increase in short-term height. Measuring IGF-1 levels is recommended as part of the assessment during the follow-up of patients with TRPS I.

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

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

Expert Opinion on the Management of Growth Hormone Deficiency in Brain Tumor Survivors: Results From an Italian Survey.

Background: Growth hormone deficiency (GHD) is the first and most common endocrine complication in pediatric brain tumor survivors (BTS). GHD can occur due to the presence of the tumor itself, surgery, or cranial radiotherapy (CRT). Aims: This study aimed to evaluate management and adherence to current guidelines of the Italian centers engaged in the diagnosis and follow-up of GHD patients with BTS. Methods: A multidisciplinary scientific board of pediatric endocrinologists, oncologists and radiologists with neuroimaging expertise discussed and reviewed the main issues relating to the management of GHD in pediatric BTS and developed a survey. The survey included questions relating to organizational aspects, risk factors, diagnosis, definition of stable disease, and treatment. The online survey was sent to an expanded panel of specialists dedicated to the care of pediatric BTS, distributed among the three specialty areas and throughout the country (23 Italian cities and 37 Centers). Results: The online questionnaire was completed by 86.5% (32 out of 37) of the Centers involved. Most had experience in treating these patients, reporting that they follow more than 50 BTS patients per year. Responses were analyzed descriptively and aggregated by physician specialty. Overall, the results of the survey showed some important controversies in real life adherence to the current guidelines, with discrepancies between endocrinologists and oncologists in the definition of risk factors, diagnostic work-up, decision-making processes and safety. Furthermore, there was no agreement on the neuroimaging definition of stable oncological disease and how to manage growth hormone therapy in patients with residual tumor and GHD. Conclusions: The results of the first Italian national survey on the management of GHD in BTS highlighted the difference in management on some important issues. The time to start and stop rhGH treatment represent areas of major uncertainty. The definition of stable disease remains critical and represents a gap in knowledge that must be addressed within the international guidelines in order to increase height and to improve metabolic and quality of life outcomes in cancer survivors with GHD.