Efficacy and Safety of Parathyroid Hormone Replacement With TransCon PTH in Hypoparathyroidism: 26-Week Results From the Phase 3 PaTHway Trial

Hypoparathyroidism: diagnosis, management and emerging therapies

Hypoparathyroidism is characterized by inadequate parathyroid hormone (PTH) secretion or action and results in hypocalcaemia, and can lead to hyperphosphataemia and hypercalciuria. Most cases of hypoparathyroidism occur as a complication of surgery, with the remainder due to causes including autoimmune disease, genetic causes, infiltrative diseases, mineral deposition or due to abnormalities in serum levels of magnesium. Hypoparathyroidism can cause multisystem disease, with long-term complications resulting from ectopic calcification as well as renal complications with nephrocalcinosis, nephrolithiasis and renal impairment in addition to respiratory, cardiac or neurological manifestations. Conventional therapy consists of oral calcium salts and active vitamin D but it has limitations, including fluctuations in serum levels of calcium and a high pill burden, and can increase the risk of long-term complications. By contrast, PTH replacement therapy can effectively achieve normal serum levels of calcium, and lower serum levels of phosphate. The long-acting PTH analogue, palopegteriparatide, has been shown to normalize urine levels of calcium. In addition, PTH replacement therapy reduces the pill burden. Palopegteriparatide is also associated with improved quality of life in comparison to conventional therapy. This Review summarizes current recommendations regarding the pathophysiology, evaluation and management of hypoparathyroidism and also references the 2022 international hypoparathyroidism guidelines. Palopegteriparatide has now been approved as PTH replacement therapy for hypoparathyroidism. Emerging therapies will also be presented in this Review.

Prolonging parathyroid hormone analog action in vitro and in vivo through peptide lipidation

Parathyroid hormone (PTH) analogs with improved actions in vivo could lead to optimized treatments for bone and mineral ion diseases. Rapid clearance from the circulation and short dwell times on the PTH receptor limit the efficacies of conventional PTH peptides currently in medical use. Here, we seek to enhance PTH peptide efficacy using two distinct peptide lipidation strategies. First, we append a lipid chain to the peptide's C-terminus in a fashion to promote binding to serum albumin and hence prolong the peptide's circulation half-life in vivo. Second, we append a lipid chain to a lysine side chain in a fashion designed to anchor the peptide to the cell membrane as the ligand is bound to the receptor and hence increase its dwell time on the receptor. We find that both strategies of lipidation can profoundly enhance the efficacy of PTH peptides in vitro and in mice. Our results could lead to the development of modified PTH analogs with optimized therapeutic utility.

Permanent hypoparathyroidism following total thyroidectomy - Incidence and preventative strategies without imaging adjuncts

INTRODUCTION

Permanent hypoparathyroidism (pHypoPT) is the most common permanent complication of total thyroidectomy. We aim to describe the incidence and predictors of hypoparathyroidism in a consecutive series of patients treated in a high-volume centre and define strategies to reduce the risk of pHypoPT.

METHODS

1182 patients who underwent total thyroidectomy between April 2018 and June 2022 were analyzed. Temporary hypoparathyroidism (tHypoPT) was defined as PTH <0.4 ​pmol/L (<4 ​pg/mL) at day one post-operatively, or clinical or biochemical evidence of hypocalcemia. pHypoPT was defined as an ongoing need for calcitriol supplementation to maintain normocalcemia at 12 months. Symptomatic tHypoPT (OR 43.97, p ​< ​0.001) and number of parathyroid glands in the operative specimen (OR 2.31, p ​= ​0.022) were also significantly associated with pHypoPT.

RESULTS

Biochemical tHypoPT occurred in 205 (17.4 ​%) patients whilst pHypoPT occurred in 6 (0.5 ​%) patients. On multivariate analysis, parathyroid auto-transplantation (PA) independently reduced the risk of pHypoPT (OR 0.04, p ​= ​0.004).

CONCLUSIONS

The risk of pHypoPT after total thyroidectomy is 0.5 ​% when performed by high-volume surgeons. PA represents an important technique that reduces the risk of pHypoPT.

A year in pharmacology: new drugs approved by the US Food and Drug Administration in 2024

The US Food and Drug Administration approved 50 new drugs and nine new cellular and gene therapy products in 2024, i.e., a total of 59 new medical therapies. The latter group represented three treatments each for oncology and hematology/immunotherapy, and one each for neurology, genetic disorders, and cardiovascular disorders. Oncology, hematology/immunotherapy, and neurological disorders (14, six, and seven, respectively) also were highly prevalent among classic medications. Looking at trends over the past 5 years, we observe a greater share in first-in-class medications, more fast-track approvals, and mRNA/gene/cell-based therapies. While small molecules remain the largest fraction, their percentage has been declining substantially over the past 5 years. Taking together, these findings testify to the commitment of the pharmaceutical industry for innovative treatments, including conditions for which no approved therapies existed. On the other hand, there also is a trend for approvals for narrowly focused conditions such as tumors defined by genetic alterations.

Normative values for the hypoparathyroidism patient questionnaire (HPQ28) in the German general population

BACKGROUND

Patients with hypoparathyroidism (HypoPT) suffer from several complaints and reduced quality of life (QoL), even if disease-specific biochemical parameters are within the target range. To be able to quantify symptoms in HypoPT patients, we recently developed a disease-specific questionnaire, the Hypoparathyroidism Patient Questionnaire with 28 items (HPQ28). The aim of this study was to find normative values for the HPQ28 in the German general population.

METHODS

We tasked an independent market and social research institute to obtain sociodemographic data and HPQ28 results from a representative sample of the German general population. The HPQ28 comprises five scales and three single items. The five scales indicate different areas of complaints: Pain and cramps (PaC) including five items, neurovegetative symptoms (NVS) including five items, loss of vitality (LoV) including six items, depression and anxiety (DaA) including five items, gastro-intestinal symptoms (GiS) including two items and two control items for depression. Three items were not attributable to any of the five scales: numbness and tingling in certain parts of the body (NT), troubled memory (TM), and racing heart (RH).

RESULTS

Mean age (± standard deviation) in the representative general population sample (n = 2506) was 49.5 ± 17.8 years, 51% were female. All scales and single items were affected by gender with women presenting significantly more complaints on every scale and single item in comparison to men (p < 0.01, Mann-Whitney U test). In addition, all scales and single items, except for GiS, were affected by age in males and females (p < 0.001, Spearman's correlation). Regression analyses proved a linear trend in the different scores regarding age and gender (p < 0.05 except for age on the GiS scale).

CONCLUSIONS

We present data from the first application of the HPQ28 in a representative sample of the German general population. Almost all scales and single item of the HPQ28 were dependent on age and gender, with older individuals and females presenting a higher burden of complaints.

TRIAL REGISTRATION

DRKS, DRKS00027581. Registered 17th of January 2022, https//drks.de/search/de/trial/DRKS00027581.

Skeletal health status among patients with chronic hypoparathyroidism: results from the Canadian National Hypoparathyroidism Registry (CNHR)

In the CNHR study, 35% of postmenopausal women had osteoporosis by BMD or fragility fracture, and 4% had both. Three men ≥ 50 had osteoporosis by BMD or fragility fracture (33.3%; n = 3/9). This suggests that close follow-up of skeletal health is necessary in postmenopausal women, and men ≥ 50 with chronic HypoPT.

PURPOSE

Chronic hypoparathyroidism (HypoPT) has been associated with decreased bone turnover and abnormalities in bone mineral density (BMD), microarchitecture, and strength. Current guidelines do not recommend systematic evaluation of skeletal health in patients with chronic HypoPT. Our study assessed skeletal health in pre- and postmenopausal women with chronic HypoPT and adult men.

METHODS

This prospective study enrolled adults with chronic HypoPT from the Canadian National Hypoparathyroidism Registry. Clinical characteristics, bone fractures, biochemistry, and serum bone biomarkers were assessed at baseline. Skeletal health evaluation included assessments of fragility fractures, BMD at lumbar spine (LS), femoral neck (FN), total hip (TH), 1/3 radial sites, trabecular bone score (TBS), and bone biomarkers.

RESULTS

We present the baseline data of the patients enrolled in the registry. We analyzed a total of 101 patients: 18 men, 35 premenopausal, and 48 postmenopausal women. The mean (SD) age at the onset of HypoPT was 40.7 (16.8) years, and the average disease duration was 11.2 (8.6) years. The most common etiology was postsurgical (74.3% vs. 25.7% non-surgical). Most patients received calcium supplements (89%) and active vitamin D (80%) at baseline. No fragility fractures or low BMD were reported in premenopausal women. However, BMD at LS, FN, TH, and TBS were significantly lower in postmenopausal compared to premenopausal women.

CONCLUSIONS

Overall, 35% of postmenopausal women had osteoporosis by BMD or prior fragility fracture, and 4% had both. Three men ≥ 50 years had osteoporosis by BMD or fragility fracture (33.3%; n = 3/9). This study suggests that close follow-up of skeletal health is necessary in postmenopausal women with chronic HypoPT and men ≥ 50 years.

Management of autosomal dominant hypocalcemia type 1: Literature review and clinical practice recommendations

PURPOSE

Autosomal Dominant Hypocalcemia type 1 (ADH1), caused by gain-of-function variants in the calcium-sensing receptor (CASR), is characterized by a variable degree of hypocalcemia and hypercalciuria with inappropriately low PTH. The clinical spectrum is broad, ranging from being asymptomatic to presenting with severe clinical features of hypocalcemia and end-organ damage such as nephrolithiasis and intracerebral calcifications. Although the underlying pathophysiology is different, ADH1 patients are often managed as patients with 'classical' primary hypoparathyroidism, possibly leading to (exacerbation of) hypercalciuria. New treatments such as PTH analogues and calcilytics directly targeting the CASR are in the pipeline. Specific clinical guidance for treatment and monitoring of ADH1 patients is lacking. The purpose of this study is to provide a literature review on management of ADH1, including new therapies, and to formulate practice recommendations.

METHODS

We searched for articles and ongoing clinical trials regarding management of ADH1.

RESULTS

Forty articles were included. First we review the conventional treatment of ADH1, focusing on active vitamin D, calcium supplements, thiazide diuretics, phosphorus binders and dietary recommendations. In a second part we give an overview of studies with emerging treatments in ADH1: PTH analogues (PTH1-34, rhPTH1-84, TransCon PTH and others) and calcilytics (preclinical studies and clinical trials). In a third part we discuss literature findings regarding monitoring of ADH1 patients. Finally, we formulate clinical practice recommendations.

CONCLUSION

We provide an overview of conventional and new treatments for ADH1 patients. Based on these data, we propose practical recommendations to assist clinicians in the management of ADH1 patients.

Efficacy and Safety of TransCon PTH in Adults With Hypoparathyroidism: 52-Week Results From the Phase 3 PaTHway Trial

CONTEXT

Conventional therapy for hypoparathyroidism aims to alleviate symptoms of hypocalcemia but does not address insufficient parathyroid hormone (PTH) levels.

OBJECTIVE

Assess the long-term efficacy and safety of TransCon PTH (palopegteriparatide) for hypoparathyroidism.

DESIGN

Phase 3 trial with a 26-week, double-blind, placebo-controlled period followed by a 156-week, open-label extension (OLE).

SETTING

Twenty-one sites across North America and Europe.

PARTICIPANTS

A total of 82 adults with hypoparathyroidism were randomized and received study drug and 78 completed week 52.

INTERVENTION(S)

All OLE participants received TransCon PTH administered once daily.

MAIN OUTCOME MEASURE(S)

Multicomponent efficacy endpoint: proportion of participants at week 52 who achieved normal serum calcium (8.3-10.6 mg/dL) and independence from conventional therapy (≤600 mg/day of elemental calcium and no active vitamin D). Other efficacy endpoints included patient-reported outcomes and bone mineral density. Safety was assessed by 24-hour urine calcium and treatment-emergent adverse events.

RESULTS

At week 52, 81% (63/78) met the multicomponent efficacy endpoint, 95% (74/78) achieved independence from conventional therapy, and none required active vitamin D. Patient-reported outcomes showed sustained improvements in quality of life, physical functioning, and well-being. Mean bone mineral density Z-scores decreased toward age- and sex-matched norms from baseline to week 52. Mean (SD) 24-hour urine calcium excretion decreased from 376 (168) mg/day at baseline to 195 (114) mg/day at week 52. Most treatment-emergent adverse events were mild or moderate and none led to trial discontinuation during the OLE.

CONCLUSION

At week 52 of the PaTHway trial, TransCon PTH showed sustained efficacy, safety, and tolerability in adults with hypoparathyroidism.

MBX 2109, A Once-Weekly Parathyroid Hormone Replacement Therapy Prodrug: Phase 1, First-In-Human, Randomized Trial

CONTEXT

Hypoparathyroidism denotes parathyroid hormone (PTH) deficiency and impaired mineral metabolism. MBX 2109, a novel prodrug yielding a biologically active PTH peptide agonist (PTH[1-32], extended by a fatty acylated Lys33), is being developed as a long-acting, once-weekly PTH replacement therapy.

OBJECTIVE

Here, we report the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of MBX 2109 in healthy volunteers.

METHODS

This phase 1, randomized, double-blind, placebo-controlled, multiple ascending-dose study (NCT05158335) enrolled healthy adults, who were randomly assigned 4:1 to receive MBX 2109 (200, 400, 600, and 900 μg; n = 8) or placebo (n = 2) by subcutaneous administration once weekly for 4 doses (days 1, 8, 15, and 22). The primary end point was safety and tolerability. Key secondary end points were PK and PD.

RESULTS

Overall, 40 participants (MBX 2109 n = 32, placebo n = 8) were randomly assigned (mean age, 43.3 years; 22.5% female). Treatment-emergent adverse events (TEAEs) occurred in 50% to 88% of MBX 2109 groups and in 25% of placebo participants. In the MBX 2109 groups, no severe or serious TEAEs were observed. Injection-site reaction was the most common treatment-related TEAE. The half-lives were 79 to 95 hours for MBX 2109 and 184 to 213 hours for the fatty-acylated biologically active PTH peptide, which showed dose- and time-dependent exposure increases.

CONCLUSION

The sustained-action PTH prodrug MBX 2109 was well tolerated with no unexpected, off-target safety issues. The long half-life and flat exposure profile of MBX 2109's biologically active PTH agonist supports once-weekly administration. MBX 2109 doses were identified for future studies.

Significance of QTc Interval in Chronic Hypoparathyroidism and its Correlates

CONTEXT

Hypocalcemia predisposes patients with chronic hypoparathyroidism (cHypoPT) to an increased risk of QTc prolongation and life-threatening arrhythmias. Information on clinical and biochemical correlates of QTc in cHypoPT is limited.

OBJECTIVE

To assess the significance of QTc interval in chronic hypoparathyroidism and its correlates.

METHODS

This was an observational cohort study at a tertiary care center. Eighty-eight nonsurgical patients with cHypoPT (mean age 44.1 ± 15.4 years, 45 males) were assessed for QTc interval and its possible correlates including arrhythmic symptoms (palpitation/giddiness/syncope), serum total calcium, phosphate, 25(OH)D, and intact parathyroid hormone.

RESULTS

The mean QTc in the HypoPT cohort was 428 ± 34 ms with 13.6% having prolonged QTc. There was a significant inverse correlation between QTc interval and serum total calcium measured on the same day (r = -0.43, P < .001). The mean serum total calcium was significantly lower in patients with prolonged QTc (7.05 ± 1.94 vs 8.49 ± 1.01 mg/dL, P = .02). Of patients with cHypoPT 21.6% had arrhythmic symptoms. They had significantly higher mean QTc (P = .02) and also tended to have lower mean serum total calcium during follow-up (P = .06). In multivariable regression, female gender, higher current age, higher body mass index, and low serum total calcium showed significant association with prolonged QTc. For every mg/dL decrease in serum total calcium, QTc increased by 13 ms. Receiver operating characteristic analysis revealed serum total calcium at cut-off of 8.3 mg/dL discriminated prolonged QTc with area under the curve being 0.72 (95% CI 0.51, 0.93).

CONCLUSION

One-fifth of patients with cHypoPT had arrhythmic symptoms and a significant proportion had prolonged QTc. This highlights the need for close monitoring of patients with cHypoPT for arrhythmic symptoms and QTc prolongation. The serum total calcium should be maintained to at least 8.3 mg/dL to minimize the risk of potentially life-threatening arrhythmia in cHypoPT.

Impaired renal function in patients with permanent hypoparathyroidism after thyroidectomy: analysis of a nationwide cohort in Spain

PURPOSE

We aimed to assess the decline in renal function in patients with chronic postoperative hypoparathyroidism.

METHODS

We performed a multicenter, retrospective cohort study including patients with chronic hypoparathyroidism lasting ≥ 3 years. We evaluated the changes in serum creatinine and estimated glomerular filtration rate (eGFR) before surgery and at the last visit. Changes were evaluated in absolute value (ΔeGFR = eGFR at last visit - eGFR before thyroidectomy) and corrected for time (ΔeGFR/yr = ΔeGFR / time in years).

RESULTS

We included 236 patients with hypoparathyroidism (85.6% women, median age 47 [37-58] years, median time of follow-up 7.3 [5.0-11.0] years), and 458 control subjects with similar age, gender, and time of follow-up. Before thyroidectomy we found no significant differences in serum creatinine levels or eGFR between patients and controls. At the end of follow-up, ΔeGFR and ΔeGFR/yr in the patients with hypoparathyroidism were -4.87 (-17.0-0.00) ml/min/1.73 m2 and -0.68 (-2.31-0.00) ml/min/1.73 m2 per year, respectively, whereas in the control subjects these changes were 0.00 (-10.10-4.00) ml/min/1.73 m2 (P < 0.001), and 0.00 (-1.34-0.54) ml/min/1.73 m2 per year (P < 0.001). In multivariable regression analysis the annual eGFR decline in patients with hypoparathyroidism was related to age (P < 0.001), eGFR before thyroidectomy (P < 0.001), and incident nephrolithiasis (P = 0.028).

CONCLUSION

The decline in renal function over time is significantly higher in patients with chronic hypoparathyroidism after thyroidectomy compared to thyroidectomized patients without hypoparathyroidism. Age, preoperative eGFR and nephrolithiasis are the main determinants of renal function loss in these patients.

Adaptation and validation of the French version of the Hypoparathyroid Patient Questionnaire 28 (HPQ28) in the ComPaRe-Epi-Hypo e-cohort

Chronic hypoparathyroidism is a rare disease associated with an impaired quality of life. Recommendations suggest frequent monitoring of quality of life, but for French-speaking people, only generic scales are available despite the fact that chronic hypoparathyroidism has specific symptoms and impact. The aim of this study was to adapt and validate the French version of Hypoparathyroid Patient Questionnaire 28 (HPQ28), an already validated tool in patients living with chronic hypoparathyroidism, available in English and German. HPQ28 was translated and back-translated from English into French. Translations were harmonized with the original author. Assessment of psychometric properties of the French version of HPQ28 was performed in the ComPaRe-Epi-Hypo e-cohort, a nationwide cohort of adult patients living with chronic hypoparathyroidism in France. Internal consistency was evaluated using Cronbach's alpha. Dimensional validity was studied using confirmatory factor analysis (CFA). Construct validity compared the answers from the French version of HPQ28 with those from the EQ-5D-5L, EQ-5D-VAS, and MYMPO2 instruments. Reliability was evaluated by the intra-class correlation coefficient (ICC) of a test-retest within a 2-wk interval. Between August 2023 and August 2024, 183 patients completed HPQ28, EQ-5D, and MYMOP2 scales. The majority (92%) of the participants were women, with a median[IQR] age of 52[44;60]. Etiology of the disease was neck surgery and genetic abnormalities in 82% and 8% of cases, respectively. Internal consistency was good (Cronbach's alpha 0.93, 95% CI 0.91 to 0.94). CFA found a unidimensional structure of the questionnaire. Construct validity showed positive correlation with MYMOP2 (r = 0.64) and negative correlations with EQ-5D VAS (r = -0.49) and EQ-5D-5L (r = -0.64) scores, as hypothesized. Reliability was adequate, with an ICC of 0.88 (95% CI 0.84 to 0.91). In conclusion, we adapted and validated HPQ28 for French-speaking patients suffering from chronic hypoparathyroidism. It can therefore now be used for both research and clinical follow-up.

Hypoparathyroidism: Similarities and differences between Western and Eastern countries

BACKGROUD

Hypoparathyroidism (hypoPT) is characterized by acute and chronic complications due to insufficient parathyroid hormone (PTH) production or action. Several management guidelines have been developed, but mostly based on evidence from Western countries. Data from Eastern countries have not been systematically compared with those from Western countries.

METHODS

Literatures regarding to the epidemiology, genetics, risk factors, clinical manifestations and therapies for hypoPT in Easten and Western countries, including China, South Korea, Japan, India, and USA, Canada, Italy, and etc., were searched through PubMed and CNKI. This review was officially endorsed by European Calcified Tissue Society (ECTS) board.

RESULTS

Postoperative hypoPT is the major form of hypoPT in both Western and Eastern countries. The genetic profiles and clinical features of hypoPT are similar in Eastern and Western countries. The most commonly used medications in Eastern countries are calcium and native vitamin D or active vitamin D analogues, similar to their Western counterparts. While PTH replacement therapy is not available and approved to use in most Eastern countries.

CONCLUSION

Physicians and surgeons should follow the guidelines on the management of thyroid nodules, taking more care of protecting parathyroid glands during surgery. The cross-talk between East and West in the management of hypoPT should be continued. Direct comparisons of the management strategies in patients with hypoPT between Eastern and Wester countries regarding to the morbidity, mortality, quality of life, optimal dosage, efficacies and side-effects of conventional therapies or newer medications, as well as pharmacogenetics and pharmacoeconomics, would be valuable.

PTH Substitution Therapy for Chronic Hypoparathyroidism: PTH 1-84 and Palopegteriparatide

PURPOSE OF REVIEW

to describe and compare the efficacy and safety of the main PTH treatments, namely PTH(1-84) and palopegteriparatide, for the management of hypoparathyroidism.

RECENT FINDINGS

neither PTH (1-84) nor PTH(1-34) have been shown a clear and consistent favorable impact on the 24 h urinary calcium excretion normalization, while the positive effect on quality of life is still debated. Recently, the Food & Drug Administration and the European Medicines Agency approved palopegteriparatide as the first true replacement therapy for hypoPT management. Palopegteriparatide is a prodrug of PTH(1-34), administered once daily, and designed to provide continuous exposure to released PTH over a 24-h dosing period. According to phase II and phase III studies, palopegteriparatide seems to fill the gaps identified in existing therapies for hypoPT. Palopegteriparatide is the first real replacement therapy for the management of hypoparathyroidism and seems to fill the gaps identified in existing therapies for hypoPT.

2024 FDA TIDES (Peptides and Oligonucleotides) Harvest

In 2024, the FDA approved fifty novel drugs, including four peptides and oligonucleotides (TIDEs) (two pepTIDEs and two oligonucleoTIDEs), highlighting their increasing importance as effective alternatives to traditional drug classes. TIDEs provide essential therapies for complex diseases, such as genetic disorders, rather than merely addressing symptoms. In addition to oligonucleotide therapeutics for various genetic conditions, peptides became the first approved treatment for Rett Syndrome in 2023 and were also used to treat Niemann-Pick disease type C (NPC) in 2024. Interestingly, among the strategies employed in recent approvals to enhance stability and/or delivery, the prodrug approach, exemplified by palopegteriparatide and pegulicianine, is emerging as a more targeted and precise therapeutic strategy. Additionally, the Enhanced Stabilization Chemistry (ESC)-GalNAc platform has been expanded for hepatic delivery of a new oligonucleotide drug, olezarsen. Furthermore, novel modifications to the ribose moiety in oligonucleotides, such as the 3'-amino substitution in imetelstat, enhance their stability. This review examines the TIDES approved in 2024 based on their chemical structure, medical targets, modes of action, administration routes, and common adverse effects. In addition, it highlights how the prodrug strategy has improved targeting efficiency and extended the half-lives of the active drugs.

Hypoparathyroidism: an update on new therapeutic approaches

BACKGROUND

Hypoparathyroidism is a rare endocrine disease characterized by insufficient parathyroid hormone (PTH) secretion by the parathyroid glands, leading to hypocalcemia. In contrast to most hormone deficiencies for which hormone replacement is currently the mainstay of therapy, hypoparathyroidism has conventionally been treated with calcium supplements and active analogs of vitamin D. Although the advent of a replacement therapy with 1-34 and 1-84 PTH represented a major step in the therapeutic history of hypoparathyroidism, several new molecules and different management strategies have recently been developed.

PURPOSE

This review investigates the therapeutic approaches currently under investigation for the treatment of hypoparathyroidism. Clinical trials results have been considered and discussed.

The Delicate Balancing of Pros and Cons in the Surgical Management of Hyperparathyroidism in a Young Female with Germline Variant in the CDC73 Gene

Hyperparathyroidism-jaw tumor syndrome is a rare form of syndromic primary hyperparathyroidism. We describe a young female with a history of common precursor B acute lymphoblastic leukaemia who was diagnosed with overt primary hyperparathyroidism due to a pathogenic CDC73 variant (c.25C > T). This patient posed several challenging management aspects: the development of nephrocalcinosis, the risk for parathyroid carcinoma, and persistent hyperparathyroidism after two selective parathyroidectomies, leading to the decision to perform a total parathyroidectomy. The latter resulted in permanent complete hypoparathyroidism, with subsequent difficult medical therapy. This case report illustrates the challenge to identify the optimal treatment of parathyroid disease in the context of hyperparathyroidism-jaw tumor syndrome, balancing the risks of hyperparathyroidism and parathyroid carcinoma against the burden of permanent hypoparathyroidism at young age.

New insights into the vitamin D/PTH axis in endocrine-driven metabolic bone diseases

BACKGROUND

Endocrine regulation of bone metabolisms is the focus of the "Skeletal Endocrinology" series of meetings.

AIMS

To report on the outcome of the discussion on the role of vitamin D/PTH axis in endocrine osteopathies held during the 10th Skeletal Endocrinology Meeting which took place in Stresa (Italy) in March 2023.

OUTCOMES

Vitamin D/PTH axis has relevant influence on several outcomes in the general population and in patients affected by endocrinopathies such as hypoparathyroidism and secreting pituitary adenomas.

CONCLUSIONS

Assessing the status of the vitamin D/PTH axis and using vitamin D and PTH as therapeutic agents is mandatory in several endocrine-related bone metabolic conditions.

An Open-label Phase 2 Study of Eneboparatide, a Novel PTH Receptor 1 Agonist, in Hypoparathyroidism

CONTEXT

Hypoparathyroidism is a rare disorder characterized by a deficiency in PTH resulting in hypocalcemia, hyperphosphatemia, and hypercalciuria. Eneboparatide is an investigational peptide agonist of the PTH1 receptor for the treatment of chronic hypoparathyroidism (HP).

OBJECTIVE

To evaluate the efficacy, safety, and tolerability of eneboparatide in HP patients.

DESIGN

Open-label, phase 2 study.

PARTICIPANTS

Twenty-eight patients (21 women, 7 men), mean age (range): 58 years (28-72), with HP were enrolled into 2 consecutive cohorts (C1, n = 12 and C2, n = 16).

INTERVENTION

Following an optimization period, daily subcutaneous injections of eneboparatide were administered for 3 months at a 20 µg/day (C1) or 10 µg/day (C2) starting dose. Conventional therapy was progressively removed, and eneboparatide could be titrated up to 60 µg (C1) or 80 µg (C2).

MAIN OUTCOMES

Proportion of patients achieving independence from conventional therapy, albumin-adjusted serum calcium (ADsCa), 24-h urine calcium (uCa), serum bone turnover markers (serum carboxy-terminal telopeptide of type I collagen and procollagen 1 intact N-terminal propeptide), bone mineral density (BMD), and adverse events (AEs).

RESULTS

After 3 months, ≥ 88% of patients achieved independence from conventional therapy while mean ADsCa was maintained within target range (7.8-9 mg/dL). Eneboparatide induced a rapid and sustained reduction of mean 24-hour uCa, even among patients with hypercalciuria. Bone turnover markers slightly increased, and BMD remained unchanged, consistent with progressive resumption of physiologic bone turnover. Eneboparatide was well tolerated with no serious AEs.

CONCLUSION

Eneboparatide allowed independence from conventional therapy and maintenance of serum calcium within a target range while normalizing uCa excretion and producing a balanced resumption of bone turnover.

Hypoparathyroidism update

PURPOSE OF REVIEW

Since the release of the 2022 Second International Workshop Evaluation and Management of Hypoparathyroidism Summary Statement and Guidelines, updates and advances are now available in the cause, complications, and treatment of adult chronic hypoparathyroidism (hypoPTH). This review aims to highlight these new findings and implications to patient care.

RECENT FINDINGS

Postsurgical hypoparathyroidism remains the most common cause, immune-related hypoparathyroidism from checkpoint inhibitors is an emerging autoimmune cause. In a large retrospective cohort study of thyroidectomies, incident fracture was lower, particularly in the vertebra, in the hypoPTH cohort, compared with postthyroidectomy control group. Hypercalciuria increases risk for renal calculi in hypoPTH independent of disease duration and treatment dose. Quality of life is impaired in hypoPTH patients on conventional therapy, improvement was noted post-PTH replacement. TranCon PTH phase 3 RCT reported eucalcemia with reduced renal calcium excretion, normalization of bone turn-over markers, stable BMD and improved quality of life.

SUMMARY

HypoPTH is a chronic disease associated with significant morbidity and poor Quality of Life. Awareness of treatment targets and follow-up investigations can alleviate patient anxiety regarding over-treatment and under-treatment. Progress in long-acting PTH replacement strategies might provide accessible, feasible alternatives to conventional therapy in brittle hypoPTH patients.

Quality of life in patients with hypoparathyroidism receiving standard treatment: an updated systematic review

PURPOSE

Hypoparathyroidism is defined by hypocalcemia with inappropriately normal or low parathyroid hormone levels. The current standard treatment consists of lifelong calcium and/ or vitamin D supplementation. Even while on stable treatment regimens, hypoparathyroid patients might still suffer from symptoms that can negatively impact their quality of life.

METHODS

A systematic literature review to identify the current knowledge regarding quality of life in patients with hypoparathyroidism receiving standard treatment was performed on November 1st, 2023. PubMed as well as Web of Science were searched. The systematic review is registered in PROSPERO (#CRD42023470924).

RESULTS

After removal of duplicates, 398 studies remained for title and abstract screening, after which 30 were included for full-text screening. After exclusion of seven studies with five studies lacking a control population, one using a non-validated questionnaire, and one being a subsample of the larger included study, 23 studies were included in this systematic review. The majority of the included studies used a guideline-conform definition of hypoparathyroidism, and the SF-36 was the most often applied tool. Almost all studies (87%) reported statistically significantly lower scores in at least one quality of life domain compared to a norm population or controls.

CONCLUSION

Patients with hypoparathyroidism receiving standard treatment report impairments in quality of life. The reasons for these impairments are probably multifaceted, making regular monitoring and the inclusion of various professionals necessary.

Palopegteriparatide Treatment Improves Renal Function in Adults with Chronic Hypoparathyroidism: 1-Year Results from the Phase 3 PaTHway Trial

INTRODUCTION

Individuals with chronic hypoparathyroidism managed with conventional therapy (active vitamin D and calcium) have an increased risk for renal dysfunction versus age- and sex-matched controls. Treatments that replace the physiologic effects of parathyroid hormone (PTH) while reducing the need for conventional therapy may help prevent a decline in renal function in this population. This post hoc analysis examined the impact of palopegteriparatide treatment on renal function in adults with chronic hypoparathyroidism.

METHODS

PaTHway is a phase 3 trial of palopegteriparatide in adults with chronic hypoparathyroidism that included a randomized, double-blind, placebo-controlled 26-week period followed by an ongoing 156-week open-label extension (OLE) period. Changes in renal function over 52 weeks (26 weeks blinded + 26 weeks OLE) were assessed using estimated glomerular filtration rate (eGFR). A subgroup analysis was performed with participants stratified by baseline eGFR < 60 or ≥ 60 mL/min/1.73 m2.

RESULTS

At week 52, over 95% (78/82) of participants remained enrolled in the OLE and of those, 86% maintained normocalcemia and 95% achieved independence from conventional therapy (no active vitamin D and ≤ 600 mg/day of calcium), with none requiring active vitamin D. Treatment with palopegteriparatide over 52 weeks resulted in a mean (SD) increase in eGFR of 9.3 (11.7) mL/min/1.73 m2 from baseline (P < 0.0001) and 43% of participants had an increase ≥ 10 mL/min/1.73 m2. In participants with baseline eGFR < 60 mL/min/1.73 m2, 52 weeks of treatment with palopegteriparatide resulted in a mean (SD) increase of 11.5 (11.3) mL/min/1.73 m2 (P < 0.001). One case of nephrolithiasis was reported for a participant in the placebo group during blinded treatment; none were reported through week 52 with palopegteriparatide.

CONCLUSION

In this post hoc analysis of the PaTHway trial, palopegteriparatide treatment was associated with significantly improved eGFR at week 52 in addition to previously reported maintenance and normalization of serum and urine biochemistries. Further investigation of palopegteriparatide for the preservation of renal function in hypoparathyroidism is warranted.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04701203.

Preclinical development of EXT608, an investigational parathyroid hormone derivative with extended half-life for the treatment of hypoparathyroidism

Hypoparathyroidism, a deficiency of parathyroid hormone (PTH), results in hypocalcemia, hyperphosphatemia, and hypercalciuria. The disease is poorly controlled by calcium and vitamin D supplements or native PTH(1-84) replacement therapy. A version of PTH is being developed using D-VITylation technology, whereby vitamin D is conjugated to a therapeutic peptide, which confers a long plasma half-life by virtue of binding to the abundant vitamin D binding protein (DBP). D-VITylation of PTH caused no reduction in activity at the PTHR1 receptor, and resulted in a plasma elimination half-life of 7-15 h in rats and 24-32 h in cynomolgus monkeys. Analysis of steady-state pharmacokinetics as a function of dose showed flat profiles with smaller peak:trough ratios at low doses, indicative of slower subcutaneous absorption. In thyroparathyroidectomized (TPTx) rats, PTH(1-34)-vitamin D conjugates restored serum calcium and phosphate levels into the normal range over the 24 h dosing period, and increased bone turnover markers and reduced bone mineral density. Urinary calcium was initially elevated, but normalized by the end of treatment on day 27. In healthy monkeys, a single dose of PTH(1-34)-vitamin D conjugates elevated serum calcium levels above the normal range for a period of 24-48 h while simultaneously reducing urinary calcium. Therefore, the lead compound, EXT608, is a promising candidate as a therapeutic that can truly mimic the endogenous activity of PTH and warrants further study in patients with hypoparathyroidism.

Impaired Quality of Life in Patients with Post-Surgical Hypoparathyroidism

BACKGROUND

Hypoparathyroidism is characterized by chronic hypocalcemia with low or abnormal parathyroid hormone levels. Thyroid surgery remains a predominant cause of hypoparathyroidism, often preventable by partial thyroidectomy. Although hypoparathyroidism can impair quality of life (QOL), data remain limited for Latin America. We aimed to characterize clinical manifestations and QOL in patients with postsurgical hypoparathyroidism.

METHODS

This case-control study included patients (>18 years) who underwent total thyroidectomy (TT) for differentiated thyroid cancer (DTC) with postsurgical hypoparathyroidism (Group 1, Cases) and those with DTC who underwent TT without postsurgical hypoparathyroidism (Group 2, Controls). Clinical records were collected, and the SF-36v2 QOL survey and a structured symptom survey were applied. A logistic multivariate regression analysis was performed.

RESULTS

This study included 106 subjects (Group 1, N=41; Group 2, N=65). Group 1 patients were younger, had a higher frequency of lymph node resection, and more frequently received Ι-131 than Group 2 patients (p<0.05). In the SF-36v2 survey, Group 1 had fewer physical-functioning scores (odds ratio, 3.8; 95% confidence interval, 1.2-11.7) and lower scores in mental and physical components than Group 2 and national records. Commonly reported symptoms include paresthesia, daily fatigue, and memory alterations. Treatment adherence rates were 56% and 71% for calcium and calcitriol, respectively. Furthermore, 24% of patients experienced one or more hypoparathyroidism drug-related adverse effects.

CONCLUSIONS

Patients with postsurgical hypoparathyroidism had an impaired QOL, a high frequency of disease-associated symptoms, and limited treatment adherence. These results should be considered when deciding the best surgical alternative for DTC.

Clinical and molecular characteristics of two Italian kindreds with hypoparathyroidism, deafness and renal dysplasia (HDR) syndrome

PURPOSE

Hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome, also known as Barakat syndrome, is a rare autosomal dominant disease characterized by the triad of hypoparathyroidism, deafness, and renal abnormalities. The disorder is caused by the haploinsufficiency of the zinc finger transcription factor GATA3 and exhibits a great clinical variability with an age-dependent penetrance of each feature. We report two unrelated kindreds whose probands were referred to our outpatient clinic for further evaluation of hypoparathyroidism.

METHODS

The proband of family 1, a 17-year-old boy, was referred for severe hypocalcemia (5.9 mg/dL) incidentally detected at routine blood tests. Abdomen ultrasound showed bilateral renal cysts. The audiometric evaluation revealed the presence of bilateral moderate hearing loss although the patient could communicate without any problem. Conversely, the proband of family 2, a 19-year-old man, had severe symptomatic hypocalcemia complicated by epileptic seizure at the age of 14 years; his past medical history was remarkable for right nephrectomy at the age of 4 months due to multicystic renal disease and bilateral hearing loss diagnosed at the age of 18 years.

RESULTS

Based on clinical, biochemical, and radiologic data, HDR syndrome was suspected and genetic analysis of the GATA3 gene revealed the presence of two pathogenetic variants in exon 3, c.404dupC and c.431dupG, in the proband of family 1 and 2, respectively.

CONCLUSION

HDR syndrome is a rare cause of hypoparathyroidism and must be excluded in all patients with apparently idiopathic hypoparathyroidism. A correct diagnosis is of great importance for early detection of other HDR-related features and genetic counseling.

[Hyper- and hypocalcemia: what should you watch out for?]

Calcium is essential for numerous metabolic processes and is hormonally controlled. These hormonal mechanisms are surprisingly effective in regulating calcium levels very reliably within a narrow range - but deviations in serum calcium levels quite often cause clinical problems. Hypercalcemia predominantly occurs in primary hyperparathyroidism or is associated with tumors (especially osteolytic processes). Hypocalcemia is usually due to hypoparathyroidism (75% surgical, 25% primary) or vitamin D deficiency. Causal calcium management requires identification of the etiology of the disorder. Symptomatic therapy depends on the severity of the electrolyte imbalance. Calcium is lowered in hypercalcemia via forced diuresis, the administration of calcitonin and bisphosphonates or denosumab, if necessary, via dialysis. Severe hypocalcemia is corrected acutely with parenteral calcium administration and any further treatment decisions and prognosis depend on the underlying disease.

Exploring Signs and Symptoms Associated with Meibomian Gland Dysfunction for Use as Clinical Trial Endpoints

Purpose: Dry eye disease is attributed to impaired tear production and/or evaporative dry eye. Evaporative dry eye is frequently associated with meibomian gland dysfunction (MGD). The objective of this study was to identify clinical study endpoints related to MGD. Methods: This 22-day, noninterventional, case-control clinical study involved three cohorts with increasing MGD severity: no MGD, mild/moderate MGD, and severe MGD. Symptoms were assessed with an ocular symptom questionnaire grading blurred vision, eye burning, eye dryness, eye pain, light sensitivity, eye itching, eye foreign body sensation, and overall ocular discomfort. Sign assessments included the maximum meibum quality score (MMQS), tear breakup time, Schirmer tear tests, biomicroscopy, and corneal staining. Signs and symptoms were compared between cohorts and study visits. Results: Seventy-five study participants were assigned to the cohorts (25 per cohort). MMQS scores increased with increasing MGD severity, reflecting the selection criteria for the cohorts. Between-visit scores showed a weighted kappa statistic of 0.72 indicating substantial agreement. Mean scores of all assessed symptoms increased with increasing MGD severity. Scores for symptoms showed moderate (κ = 0.41-0.60) to substantial (κ = 0.61-0.80) agreement between visits. Overall ocular discomfort demonstrated the strongest correlation with the MMQS. Conclusion: The MMQS was a reproducible sign of MGD showing good agreement with ocular symptoms. Overall ocular discomfort was well correlated with typical dry eye symptoms and could potentially be used as a single measure of MGD symptoms. The findings from this observational study may inform endpoints for future clinical trials. ClinicalTrials.gov NCT01979887.

Case Report: Calcium sensing receptor gene gain of function mutations: a case series and report of 2 novel mutations

Autosomal dominant hypocalcemia (ADH1) is a genetic disorder characterized by low serum calcium and low or inappropriately normal levels of parathyroid hormone. The disease is caused by a heterozygous activating mutation of the calcium-sensing receptor (CaSR) gene, encoding a G-Protein-coupled cell membrane sensor of extracellular calcium concentration mainly expressed by parathyroid glands, renal tubules, and the brain. ADH1 has been linked to 113 unique germline mutations, of which nearly 96% are missense mutations. There is often a lack of a clear genotype/phenotype correlation in the reported literature. Here, we described a case series of 6 unrelated ADH1 probands, each one bearing a gain-of-function CaSR mutation, and two children of one of these cases, matching our identified mutations to the same ones previously reported in the literature, and comparing the clinical and biochemical characteristics, as well as the complication profile. As a result of these genetic and clinical comparisons, we propose that a genotype/phenotype correlation may exist because our cases showed similar presentation, characteristics, and severity, with respect to published cases with the same or similar mutations. We also contend that the severity of the presentation is highly influenced by the specific CaSR variant. These findings, however, require further evaluation and assessment with a systematic review.

The Role of the Patient Partnership in Designing Research on Neuropsychiatric Issues in Hypoparathyroidism

Hypoparathyroidism is a rare endocrine disease that is associated with hypocalcemia and insufficient parathyroid hormone (PTH) levels. Neuropsychiatric complaints are common in hypoparathyroidism. Yet there is a large knowledge gap in our understanding of cognitive dysfunction in hypoparathyroidism and partnering with patients is essential for filling this hole. Input from hypoparathyroid patients is needed to define objective, performance-based cognitive impairments. Creating patient advisory boards that provide input for planning clinical trials would enable patient perspectives to be shared. This would ensure that meaningful, standardized neuropsychological instruments that prioritize patients' cognitive concerns are selected. Patient partnership is also needed to understand the wide inter-individual variability of cognitive symptoms in hypoparathyroidism, as well as mechanisms aside from calcium shifts that might explain cognitive symptoms, such as low PTH itself, alterations in brain structure, or other hypoparathyroidism-associated comorbidities. With new PTH replacement therapies on the horizon, patient input about studying how these therapies impact, and maybe even reverse, cognitive impairment will also be critical. Ultimately, the inclusion of patient partners in hypoparathyroidism research will advance the design of neuropsychiatric studies and generate key input for understanding how to reduce the burden of this disease.

Vitamin D in hypoparathyroidism: insight into pathophysiology and perspectives in clinical practice

Hypoparathyroidism (HypoPT) is a rare endocrine disorder characterized by the absence or insufficient parathyroid hormone production resulting in chronic hypocalcemia. Complications of HypoPT include perturbation of several target organs. The conventional treatment consists of the administration of active vitamin D, namely calcitriol. Regarding vitamin D status, few data are available, mostly in HypoPT subjects supplemented with parent vitamin D. In addition, perturbation of vitamin D metabolism has been poorly investigated, as well as the contribution of altered vitamin D status on the clinical expression of the disease. The most recent consensus on the management of chronic HypoPT suggests the baseline evaluation of serum 25-hydroxy-vitamin D [25(OH)D] and supplementation with parent vitamin D with the aim to achieve and maintain serum 25(OH)D levels in the range of 30-50 ng/mL. The rationale for using supplementation with parent vitamin D (either ergocalciferol or cholecalciferol) in HypoPT would be to provide sufficient 25(OH)D substrate to the residual 1-α-hydroxylase activity, thus ensuring its conversion to active vitamin D in renal and extra-renal tissues. More data from experimental and clinical studies are needed for better assessing how these mechanisms may significantly influence metabolic control in HypoPT and eventually skeletal and extra-skeletal manifestation of the disease. Finally, future data will clarify how the currently available parent vitamin D compounds (ergocalciferol, cholecalciferol, calcifediol) would perform in addressing these specific issues.

Management of Hypoparathyroidism

Hypoparathyroidism (HypoPT) is a rare disorder characterized by hypocalcemia in the presence of a low or inappropriately normal parathyroid hormone level. HypoPT is most commonly seen after neck surgery, which accounts for approximately 75% of cases, whereas approximately 25% have HypoPT due to nonsurgical causes. In both groups of patients, conventional therapy includes calcium and active vitamin D analogue therapy aiming to maintain serum calcium concentration in the low normal or just below the normal reference range and normalize serum phosphorus, magnesium concentrations, and urine calcium levels. The limitations of conventional therapy include wide fluctuations in serum calcium, high pill burden, poor quality of life, and renal complications. Parathyroid hormone (PTH) replacement therapy may improve the biochemical profile in those in whom conventional therapy proves unsatisfactory. Based on a systematic review and meta-analysis of the literature, the panel made a graded recommendation suggesting conventional therapy as first line therapy rather than administration of PTH (weak recommendation, low quality evidence). When conventional therapy is deemed unsatisfactory, the panel considers use of PTH. Because pregnancy and lactation are associated with changes in calcium homeostasis, close monitoring is required during these periods with appropriate adjustment of calcium and active vitamin D analogue therapy to ensure that serum calcium remains in the mid to low normal reference range in order to avoid maternal and fetal complications. Emerging therapies include molecules with prolonged PTH action as well as different mechanisms of action that may significantly enhance drug efficacy and safety. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Evaluation and Management of Hypoparathyroidism Summary Statement and Guidelines from the Second International Workshop

This clinical practice guideline addresses the prevention, diagnosis, and management of hypoparathyroidism (HypoPT) and provides evidence-based recommendations. The HypoPT task forces included four teams with a total of 50 international experts including representatives from the sponsoring societies. A methodologist (GG) and his team supported the taskforces and conducted the systematic reviews. A formal process following the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology and the systematic reviews provided the structure for seven of the guideline recommendations. The task force used a less structured approach based on narrative reviews for 20 non-GRADEd recommendations. Clinicians may consider postsurgical HypoPT permanent if it persists for >12 months after surgery. To predict which patients will not develop permanent postsurgical HypoPT, we recommend evaluating serum PTH within 12 to 24 hours post total thyroidectomy (strong recommendation, moderate quality evidence). PTH > 10 pg/mL (1.05 pmol/L) virtually excludes long-term HypoPT. In individuals with nonsurgical HypoPT, genetic testing may be helpful in the presence of a positive family history of nonsurgical HypoPT, in the presence of syndromic features, or in individuals younger than 40 years. HypoPT can be associated with complications, including nephrocalcinosis, nephrolithiasis, renal insufficiency, cataracts, seizures, cardiac arrhythmias, ischemic heart disease, depression, and an increased risk of infection. Minimizing complications of HypoPT requires careful evaluation and close monitoring of laboratory indices. In patients with chronic HypoPT, the panel suggests conventional therapy with calcium and active vitamin D metabolites as first-line therapy (weak recommendation, low-quality evidence). When conventional therapy is deemed unsatisfactory, the panel considers the use of PTH. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).