United States

Background Hypoparathyroidism (HP) is characterized by insufficient levels of parathyroid hormone (PTH), resulting in hypocalcemia, hyperphosphatemia, hypercalciuria, and a reduced quality of life (QoL). PTH replacement therapy should restore physiologic levels of PTH and restore downstream physiologic levels of calcitriol, promoting independence from Ca and active vitamin D supplements and normalization of QoL.?TransCon PTH is an investigational long-acting prodrug of PTH(1-34) for the treatment of HP. During the initial 4-week fixed-dose period of the PaTH Forward Trial, TransCon PTH enabled 82% of subjects to achieve independence from standard of care (SoC; no active vitamin D and Ca ≤ 500 mg/day) compared to 15% with placebo. Here, we report 6-month (Week 26) results from the open-label extension (OLE).?Methods PaTH Forward is a phase 2, double-blind, placebo-controlled trial evaluating TransCon PTH in adult HP patients treated with SoC. Subjects received fixed doses of TransCon PTH 15, 18, or 21 µg PTH(1-34)/day or placebo for 4 weeks, followed by an OLE period during which TransCon PTH dose was titrated (6-30 µg PTH[1-34]/day) per individual dosing requirement. Safety and efficacy endpoints were evaluated at predefined timepoints over the OLE. Endpoints were evaluated at Week 26 including 1) sCa, 2) 24-hour uCa, 3) independence from active vitamin D, and 4) independence from therapeutics doses of oral calcium. QoL was assessed by the SF-36 and the Hypoparathyroidism Patient Experience Scales (HPES).?ResultsAll 59 subjects completed the initial 4-week period and continued in the OLE; 58 subjects continue in the OLE beyond 6 months (1 withdrew unrelated to safety or efficacy). TransCon PTH enabled independence from SoC (no active vitamin D and Ca ≤ 500 mg/day) in 91% of subjects and independence from all supplements (no active vitamin D and no Ca) in 76% of subjects by Week 26. Mean 24-hour uCa decreased from a baseline mean of 415 mg/24h to 178 mg/24h by Week 26 (n = 44) while maintaining sCa, and reducing sP and CaxP to fall within the normal range. The mean scores for all SF-36 summary and domains increased from below normal at baseline to within the normal range by Week 26. The HPES Symptom and Impact scores continuously improved through 26 weeks for TransCon PTH and placebo subjects switching to TransCon PTH. TransCon PTH continued to be well-tolerated with no treatment-related serious or severe adverse events.?Conclusions Results from the OLE of the PaTH Forward Trial demonstrated that TransCon PTH continued to enable independence from active vitamin D and Ca supplements for most subjects while maintaining normal sCa, sP, uCa, and demonstrating enhanced quality of life, supporting its potential as a hormone replacement therapy for patients with HP. TransCon PTH will be further evaluated in the phase 3 PaTHway Trial.?? 

ENDO 2021

TransCon PTH as a Hormone Replacement Therapy for Patients with Hypoparathyroidism: 6-Month Update from the PaTH Forward Open-Label Extension

technical paper

XLH is the most common heritable rickets. Affected children have high levels of circulating FGF23 that cause hypophosphatemia with consequent rickets and lower limb deformity. Burosumab, a fully human monoclonal antibody that binds FGF23, is FDA-approved for the treatment of XLH in children ≥6 months old and adults. Herein, we report final, 3-year safety and efficacy data from an open-label, phase 2 study of burosumab in children 1 to <5 years old at baseline (NCT02750618).?Eligibility required hypophosphatemia and radiographic evidence of rickets. The primary efficacy endpoint was change from baseline in fasting serum phosphorus (Pi). Secondary endpoints included Rickets Severity Score (RSS) and Radiographic Global Impression of Change (RGI-C). Patients received burosumab subcutaneous Q2W starting at 0.8 mg/kg for 160 weeks (64-week treatment + 96-week treatment extension periods).?All 13 enrolled patients completed the 64-week treatment period; 1 left the study to transition to commercially available burosumab, and 12 completed all 160 weeks. Baseline mean (SD) age was 2.9 (1.1) years; 69% were boys; all had previously received oral phosphate salts and active vitamin D.?Burosumab rapidly corrected fasting serum Pi with mean (SD) levels of 2.5 (0.3) mg/dL at Baseline, 3.7 (0.5) mg/dL at Week 1 (W1), 3.4 (0.5) mg/dL at W64, and 3.4 (0.5) mg/dL at W160 (normal range: 3.2-6.1 mg/dL). Lower RSS indicated improved rickets. Total RSS decreased from 2.9 (1.4) at Baseline to 1.2 (0.5) at W40 and to 0.9 (0.5) at W64 and was maintained through W160 [1.0 (0.6)]. Positive RGI-C scores indicate healing rickets relative to Baseline. Global RGI-C scores indicating substantial healing (≥+2) at W40 [+2.2 (0.3)] and W64 [+2.2 (0.4)] were maintained through W160 [+2.2 (0.4)]. Similarly, lower limb deformity RGI-C scores were +1.2 (0.6) at W40 and +1.5 (0.5) at W64, and sustained healing was evident at W160 [+2.0 (0.3)]. Wrist and knee RSSs and RGI-C scores similarly improved. The upper limit of normal for serum ALP ranged from 297 to 345 U/L depending on the child’s age and sex. Mean ALP was 549 (194) U/L at Baseline, normalized by W40 [335 (88) U/L], and was sustained through W160 [302 (71) U/L].?The burosumab safety profile over 160 weeks resembled previous pediatric studies; no new safety concerns emerged. All patients had ≥1 treatment-emergent adverse event (TEAE). All TEAEs were mild (Grade 1) or moderate (Grade 2) except for one patient with a grade 3 TEAE (food allergy) and one with a grade 3 TEAE (increased serum amylase, 92% salivary/8% pancreatic). One patient had a serious TEAE (dental abscess leading to hospitalization). These grade 3 and serious TEAEs were considered unrelated to study drug.?Burosumab rapidly restored Pi homeostasis, improved rickets, and normalized serum ALP in children with XLH aged 1 to <5 years with no new safety concerns. Improvements were maintained during the 3 years of treatment.?? 

Burosumab Provides Sustained Improvement in Phosphorus Homeostasis and Heals Rickets in Children Aged 1 to 4 Years With X-Linked Hypophosphatemia (XLH)

Background: Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare, autosomal dominant disorder driven by mutations in ACVR1 that render it responsive to Activin A. FOP is characterized by progressive heterotopic ossification (HO) and distressing inflammatory events called “flare-ups.” Flare-ups can precede new HO; however, limited prospective data exists on this phenomenon. Garetosmab (GAR), an investigational human monoclonal antibody against Activin A, blocks formation of new HO in FOP.Methods: This is a post-hoc analysis of LUMINA-1 (NCT03188666) a phase 2, randomized, double-blind, placebo-controlled study, which evaluated the safety and efficacy of GAR (10 mg/kg/week IV) versus placebo (PBO) in adult patients with FOP over 28 weeks. Patient-reported flare-ups were collected via a patient diary and severity level was reported as mild, moderate or severe. Clinician-reported flare-ups were collected as adverse events in the trial. HO lesions were imaged by 18F-NaF positron emission tomography (PET) and whole-body low-dose X-ray computed tomography (CT).Results: There was a two-fold higher proportion of patients who reported one or more flare-ups on PBO 17/24 (71%) compared with GAR 7/20 (35%). Clinicians reported a four-fold higher proportion of patients experiencing one or more flare-ups on PBO 10/24 (42%) compared with GAR 2/20 (10%). Overall rates of flare-up events were two-fold higher on PBO vs. GAR (1.4 vs. 0.65 events/patient/28 weeks) for patient-reported events and eight-fold higher on PBO vs. GAR by clinician report (0.83 vs. 0.10 events/patient/28 weeks). Most flare-ups occurred on the extremities and back; pain was the most commonly reported symptom. Patient-reported flare-ups on PBO were more frequently reported as severe (29.4%) compared with GAR (7.7%). Among subjects with at least 12 weeks of follow-up from start of patient-reported flare-up, development of new HO near the site was 5/27 (18.5%) on PBO and (0%) on GAR. Of all new HO lesions, 41% on PBO and 0% on GAR occurred with spatial and temporal relation to flare-upConclusions: Approximately two-thirds of patients on PBO reported flare-ups over 28 weeks. GAR was associated with reductions in frequency and severity of flare-ups. Fewer than 20% of patient-reported flare-ups were associated with new HO, indicating frequent discordance of these phenomena, and compatible with previous reports. GAR’s ability to reduce patient- and clinician-reported flare-ups, as well as new HO lesions may provide an important therapeutic option.?? 

Garetosmab Reduces Flare-ups in Patients With Fibrodysplasia Ossificans Progressiva

Background: The diagnosis of non-alcoholic fatty liver disease (NAFLD) is often challenging. Blood-based biomarkers which are causally influenced by NAFLD and that are not modulated by secondary non-causal pathways, are promising candidates for the identification of patients with NAFLD.Objectives: To identify blood metabolites and blood proteins that are causally impacted by the presence of NAFLD using Mendelian randomization (MR). Methods: We created a NAFLD genetic instrument through the identification of independent single-nucleotide polymorphisms associated with NAFLD in a meta-analysis of genome-wide association studies (GWAS) (6715 cases and 682,748 controls). Using inverse-variance weighted MR, we investigated the impact of NAFLD on 123 blood metabolites (in 24,925 participants from 10 European cohorts) and 3283 blood proteins (in 3301 participants from the INTERVAL cohort). Results: Our genetic instrument for genetically predicted NAFLD included 12 SNPs at the MTARC1, GCKR, LPL, TRIB1, LMO3, FTO, TM6SF2, APOE and PNPLA3 loci. After correction for false-discovery rate, we found a positive effect of NAFLD on blood tyrosine levels and on blood levels of eight proteins (encoded by the IDUA, ADH4, HMGCS1, GSTA1, ASL, POR, FBP1 and CTSZ genes). These association were robust to outliers and we found to evidence of horizontal pleiotropy. Conclusions: We report the existence of a potentially causal impact of the presence of NAFLD on tyrosine metabolism as well as on eight circulating proteins, which could potentially represent early biomarkers of NAFLD.?? 

Genome-Wide Meta-Analysis and Mendelian Randomization Identify Early Biomarkers of Non-Alcoholic Fatty Liver Disease

Treatment of Nonalcoholic fatty liver disease (NAFLD) constitutes an unmet clinical need owing to the relatively limited efficacy of both novel and readily available metabolic medications, thus warranting pathobiological investigations on the mechanisms of single or combination regimens. In this context, our study aimed to assess and compare whether and how liraglutide, a glucagon-like peptide-1 receptor agonist, and elafibranor, a dual peroxisome proliferator-activated receptor alpha-delta agonist, may affect hepatic histology and metabolipidomic fingerprints in a model of advanced NAFLD. Male C57BL/6JRj mice with biopsy-confirmed hepatosteatosis and fibrosis induced by AMLN diet (40% fat with 20% trans-fat, 2% cholesterol and 22% fructose) were randomized to receive for 12 weeks: a) Liraglutide (0.4 mg/kg/d s.c.), b) Elafibranor (30 mg/kg/d p.o.), c) vehicle. Metabolic indices, liver function markers, liver pathology, and metabolomics/lipidomics were assessed at study completion. Both drugs markedly reduced body weight and fat percentage (p-value <0.001), and improved glucose tolerance and insulin sensitivity, as indicated by oral glucose and intraperitoneal insulin tolerance tests. Hepatic lipid content was downregulated under both treatments (p-value <0.001), especially under elafibranor, which also elevated liver weight in contrast with liraglutide (p-value vs liraglutide <0.001). NAFLD activity score (pre-to-post) and its histological components were substantially improved (mean difference ± standard error of mean: -1.4 ± 0.3 for liraglutide; -2.0 ± 0.2 for elafibranor), with elafibranor demonstrating a more robust anti-steatotic effect vs liralgutide (p-value <0.01) as well as anti-fibrotic effects (-0.5 ± 0.1). Liraglutide also limited the immunohistochemical expression of pro-inflammatory markers of Kupffer and hepatic stellate cell function (Galectin-3, Collagen type I alpha 1, and alpha-smooth muscle actin). In the omics analysis, elafibranor profoundly ameliorated the hepatic lipidome by diminishing the concentrations of glyceride species, increasing phospholipids and carnitine metabolites, and modifying key regulators of fatty acid oxidation, inflammation, and oxidative stress, including metabolites of methionine, glutathione, and pantothenate. Liraglutide significantly affected bile acid and carbohydrate metabolism by restoring the concentrations of metabolically beneficial primary and secondary bile acids, glycogen metabolism by-products, and pentoses, thus probably driving glycogen utilization-turnover and nucleic acid synthesis. Thus, liraglutide and elafibranor diverge in their mechanistic treatment of advanced NAFLD pathology, indicated by their robust but differential regulation of the hepatic metabolipidome. These findings support their combinatory therapeutic evaluation in future studies.?? 

Both Elafibranor and Liraglutide Improve NAFLD / NASH but Affect Differentially the Hepatic Lipidome and Metabolome in a Diet-Induced Obese and Biopsy-Confirmed Mouse Model of NASH

Lipodystrophy (LD) syndromes are rare disorders of deficient adipose tissue and severe metabolic disease, including insulin resistance, diabetes, and hypertriglyceridemia. LD may affect all adipose depots (generalized LD, GLD) or only some depots (partial LD, PLD). Low adipose mass leads to very low leptin in GLD, and variable leptin in PL. Treatment with exogenous leptin (metreleptin) improves metabolic disease in LD, particularly GLD. Left ventricular (LV) hypertrophy is frequent in LD, especially GLD. The mechanism for hypertrophy in LD is not known and may relate to glucose or lipotoxicity. We hypothesized that metreleptin would improve cardiac abnormalities in LD, and that this would be mediated by improvements in glucose and triglycerides (TG). We analyzed echocardiograms (echo), blood pressure (BP), heart rate (HR), and metabolic parameters in 38 subjects with LD (18 GLD, 20 PLD) who were treated with metreleptin in open-label clinical studies at the National Institutes of Health. 27 had repeat echo after 1y of metreleptin (mean 1.0 ± 0.2y), and 23 after 3 to 5y (mean 3.7±0.6y). In GLD, metreleptin significantly improved metabolic disease, including reduced TG (median(IQR) 740(403-1239), 138(88-196), 211(136-558) mg/dL at baseline, 1y, & 3-5y, P<0.0001), hemoglobin A1c (9.5±3.0, 6.5±1.6, 6.5±1.9% at baseline, 1y, & 3-5y, P<0.001), and insulin resistance by HOMA-IR (34.1 (15.2-43.5), 8.7 (2.4-16.0), 8.9 (2.1-16.4), P<0.001). Only HOMA-IR improved in PLD (P<0.01). Systolic BP and HR decreased after metreleptin in GLD (BP 120±11, 117±10, 109±16 mmHg, P=0.046; HR 89±9, 82±12, 80±16 bpm, P=0.018; at baseline, 1y, 3-5y, respectively) but not PLD. Metreleptin improved cardiac parameters in patients with GLD, including reduced posterior wall thickness (9.8±1.7, 9.1±1.3, 8.3±1.7 at baseline, 1y, & 3-5y, P<0.01), LV mass (140.7±45.9, 128.7±37.9, 110.9±29.1 at baseline, 1y, & 3-5y, P<0.01), and LV mass index (88.6±22.0, 81.6±16.9, 81.6±16.9 at baseline, 1y, & 3-5y, P<0.01). Metreleptin also improved septal e’ velocity, a measure of early diastolic cardiac function, in GLD (8.6±1.7, 10.0±2.1, 10.7±2.4 at baseline, 1y, & 3-5y, P<0.01). All changes remained significant after adjustment for BP. In GLD, multivariate variable selection models suggested that changes in posterior wall thickness and LV mass index related to metreleptin-induced reductions in TG, and changes in septal e’ velocity related to metreleptin-induced reductions in hemoglobin A1c. No changes in echo parameters were seen in PLD. These findings suggest that metreleptin improves cardiac hypertrophy and diastolic function in patients with GLD, and these improvements may be mediated by reduced lipotoxicity and glucose toxicity. The applicability of these findings to a broader, leptin-sufficient population with LV hypertrophy and/or diabetic cardiomyopathy remains to be determined.?? 

Leptin Improves Cardiac Structure and Function in Patients With Generalized Lipodystrophy

Background: ACTH is thought to contribute to aldosterone excess in primary aldosteronism (PA), possibly via aberrant melanocortin type 2 receptor (MC2R) expression in aldosterone producing adenomas (APAs). Dynamic manipulation of the hypothalamic-pituitary-adrenal (HPA) axis has been proposed as a non-invasive tool for distinguishing unilateral PA (UPA) from bilateral PA (BPA), but existing data are minimal. Objective: To characterize the steroid responses to intrinsic ACTH variations and extrinsic HPA manipulation in UPA and BPA. Methods: We conducted comprehensive dynamic testing in PA patients, who were subtyped based on adrenal vein sampling. Peripheral plasma samples were collected from each patient at 6 time-points: morning; midnight; after 1 mg dexamethasone suppression (DST); and after cosyntropin stimulation (at 15’, 30’, and 60’). We quantified 15 steroids by mass spectrometry in each sample. Next generation sequencing was used to detect aldosterone-driver somatic mutations in APAs from 39 cases with available tissue. The Mann-Whitney test, Wilcoxon signed rank test, and repeated measures two-way ANOVA were employed, as appropriate. Penalized logistic regression was used to select steroids that best distinguished UPA from BPA. Receiver operating characteristic (ROC) curves were then plotted using the predicted score from the logistic regression model with the selected steroids, and area under the curves (AUC) were computed. Results: We included 80 PA patients, median age 51 (range, 26-76), 50% men, 40 with each subtype, both groups with similar age and sex distribution. Morning and midnight concentrations of 18-hydroxycortisol (18OHF), 18-oxocortisol (18oxoF), aldosterone, and 18-hydroxycorticosterone (18OHB) were higher in patients with UPA vs. BPA (p<0.001 for all). In response to cosyntropin stimulation, the UPA group had larger increments of aldosterone, 18oxoF, 11-deoxycorticosterone, corticosterone, and 11-deoxycortisol than the BPA group (p<0.05 for all). Following DST, aldosterone,18OHF, and 18oxoF were higher in UPA than in BPA patients (p<0.01 for all). Overall, cortisol and cortisone serum concentrations were similar between the two subtypes. Of the UPA cases, 27 (69%) had KCNJ5 mutations. Relative to UPA patients with other mutations, the KCNJ5 group had higher 18oxoF and 18OHF at baseline; higher 18oxoF and corticosterone after both dynamic tests; and lower aldosterone after DST. The highest AUC for PA subtyping was achieved using cosyntropin stimulated steroids (0.957), while baseline data reached an AUC of 0.909. Conclusions: Steroid responses to dynamic HPA testing differs between UPA and BPA: 18oxoF and 18OHF are less suppressible, while several steroids are disproportionally amplified by ACTH in patients with UPA vs. BPA. Such non-invasive tests could circumvent the need for adrenal vein sampling in a subset of PA patients.?? 

The Impact of ACTH on Peripheral Steroids Differs between Unilateral and Bilateral Primary Aldosteronism

Liver-specific Expression of Constitutively Active Gsα Leads to Hyperglycemia With Impaired Insulin Secretion?The ubiquitously-expressed G protein Gsα couples hormone receptors to the stimulation of intracellular cAMP generation. We previously showed that mice with liver-specific Gsα deficiency (LGsKO) have improved glucose tolerance and enlarged pancreatic islets1. In the present study, we have generated mice with liver-specific expression of a constitutively activated Gsα (LGsR201C) by breeding mice containing a Lox-STOP-Lox-GsαR201C transgene within the Hipp11 locus with albumin-Cre mice. Male LGsR201C mice had normal survival but reduced body weight and increased liver weight. Compared to control littermates, LGsR201C mice had significantly increased hepatic cAMP levels and enhanced hyperglycemic response to glucagon, confirming the activation of liver Gsα/cAMP signaling in LGsR201C mice. As a consequence, LGsR201C mice showed elevated blood glucose levels during both fed and fasting states, as well as enhanced hepatic gluconeogenesis evidenced by pyruvate tolerance test. Serum levels of insulin, glucagon, free fatty acids and triglycerides were comparable between control and LGsR201C mice in the fed state. Results of glucose and insulin tolerance tests showed that LGsR201C mice had severe glucose intolerance with normal insulin sensitivity. Unlike control mice, when given a high dose of glucose (3mg/g ip.), LGsR201C mice had completely blunted first- and second-phase insulin secretory responses to glucose. Since LGsR201C mice exhibited normal pancreatic islet size and insulin content examined with immunohistochemistry, the impaired glucose tolerance in LGsR201C mice probably resulted from an impaired insulin secretion. Results of RNA-seq analysis revealed that an array of genes was oppositely regulated in the liver of LGsKO mice vs. LGsR201C mice. Thus, our data indicate possible organ-to-organ communication between liver and pancreatic β-cells that is regulated by liver Gsα signaling. 1.Chen M., et al., JCI 115:3217, 2005?? 

Liver-Specific Expression of Constitutively Active Gsα Leads to Hyperglycemia With Impaired Insulin Secretion

Growth hormone (GH) serves an important role in early and adult life. Reduction of GH action has been shown to increase life span in many species of animals. In fact, mice bearing a congenital disruption of GH receptor (GHR) gene (GHRKO) hold the record for the longest-lived laboratory mice. In addition to extended life span, these mice show improved health with lower rates of cancer, increased insulin sensitivity, and resistance to age-associated cognitive decline. Furthermore, humans with decreased GH action due to inactivating mutations in the GHR (Laron Syndrome patients) are resistant to cancer and diabetes. Even though the beneficial effects of congenital Ghr gene disruption are well studied, the consequences of postnatal disruption of GH action were unknown. Previously our laboratory generated a mouse line with disrupted GH action at 1.5 months of age (1.5mGHRKO mice). Results showed that these mice had improved insulin sensitivity and increased maximal lifespan only in females, yet growth retardation was still present.?To consider decreased GH action as a possible therapeutic to extend healthy lifespan, it was imperative to elucidate the effects of disrupting Ghr gene at a mature-adult age, well after the developmental and growth period of the mice. To this end, we hypothesized that removal of GH action in adult life would convey some of the same health and life span benefits seen in the GHRKO mice without the reduced body length. To test this hypothesis, we used the cre-lox system to generate mice with a disrupted Ghr gene at a mature-adult age (6 months), referred as 6mGHRKO mice. We then performed a phenotypic and lifespan characterization, and tested for molecular mechanisms known to be associated with extended longevity, namely oxidative stress resistance and mTOR modulation. We found that similar to GHRKO and 1.5mGHRKO mice, disruption of GHR at 6 months of age resulted in mice with increased adipose tissue mass, decreased lean mass, high circulating GH, but decreased insulin growth factor-1 levels compared?to control mice. Furthermore, the 6mGHRKO mice displayed significantly improved insulin sensitivity in males, with no changes in glucose tolerance. Also, serum levels of inflammatory markers and liver triglycerides were unchanged in these mice. Experiments to evaluate the status of oxidative damage and mTOR activation in liver, skeletal muscle and subcutaneous adipose tissue of male and female 6mGHRKO mice showed a tissue-specificity and sexual dimorphism in these results. Importantly, male and female 6mGHRKO mice showed no change in body length, but mean, median and maximal lifespan were significantly extended in females. In conclusion, disruption of GH action well past sexual maturation produces beneficial effects on insulin sensitivity and aging in mice.?Acknowledgements: This work is supported by the State of Ohio's Eminent Scholar Program, by NIH grant AG059779 and by the AMVETS.?? 

TransCon PTH as a Hormone Replacement Therapy for Patients with Hypoparathyroidism: 6-Month Update from the PaTH Forward Open-Label Extension

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Burosumab Provides Sustained Improvement in Phosphorus Homeostasis and Heals Rickets in Children Aged 1 to 4 Years With X-Linked Hypophosphatemia (XLH)

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