Continuous Subcutaneous Recombinant Parathyroid Hormone (1-34) Infusion in the Management of Childhood Hypoparathyroidism Associated with Malabsorption

Continuous subcutaneous rhPTH infusion for managing difficult chronic hypoparathyroidism. A systematic review

PURPOSE

Standard treatment for chronic hypoparathyroidism is represented by long-life per os supplementation of calcium and vitamin D. Since 90s, exogenous PTH is also available, but a not negligible number of patients experience a poor control. Starting from the experience with pumps in diabetes, it has been hypothesized that the infusion of PTH through pump might result in a better disease control. The aim of this systematic review is to summarize the published data about continuous subcutaneous PTH infusion in chronic hypoPTH patients and achieve conclusions for clinical practice.

METHODS

A comprehensive computer literature search of the PubMed/MEDLINE, Embase, and Scopus databases was conducted by two authors independently (last search on November 30, 2022). All findings were summarized and critically discussed.

RESULTS

We included 14 of the 103 retrieved articles, 2 RCTs, 8 case reports, and 4 case series, published between 2008 and 2022. Of the total 40 patients, 17 were adults, and 23 pediatric. The etiology was postsurgical in 50% of cases and genetic in the other 50%. All had a failure of standard care and a rapid improvement of clinical and biochemical parameters on PTH pump therapy, without severe adverse events.

CONCLUSIONS

Based on literature, pump PTH infusion may represent an effective, safe, and feasible option for patients with chronic hypoparathyroidism refractory to standard therapy. From a clinical perspective, careful patient selection, a skilled healthcare team, the assessment of the local setting and the collaboration with pump suppliers are essential.

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).

Mini-review: pump therapy in endocrinology & metabolism beyond diabetes

The first pump developed by Dr. Kadish and his team in 1963 aimed to "continue subcutaneous insulin infusion". The number of patients using insulin pumps has increased since the 1980s. This historical perspective has labeled pump therapy in endocrinology and metabolism synonymous with insulin pumps. However, certain other hormonal disorders might also benefit from this kind of treatment. Pump therapy is currently the best approach to achieve physiological mimicry. Furthermore, it may help in overcoming pharmacokinetic issues or allergies. Until now, hormone replacement via pumps has been a salvage method for complex cases at the expense of increased costs. However, it is believed that applications of pump treatment will widen in the future owing to the rapidly evolving technology. In this mini review, data on pump use for patients with adrenal insufficiency, hypogonadism, hypoparathyroidism, congenital adrenal hyperplasia, and congenital hyperinsulinism have been briefly summarized. The study has aimed at covering all the relevant clinical studies and important case reports/series. METHODS: A systematic literature search has been conducted on PubMed database seeking articles published until May 2021 using a combination of the following Medical Subject Headings terms and keywords: pump "OR" continue infusion "AND" (adrenal insufficiency "OR" Addison "OR" hydrocortisone "OR" hypoparathyroidism "OR teriparatide" "OR" somatostatin "OR" hypogonadism "OR" hypoglycemia "OR" endocrinology "OR" hormone replacement). In addition, the reference publications in the identified articles have also been reviewed.

Improving management of severe hypoparathyroidism: a case series

INTRODUCTION

Hypoparathyroidism is considered a rare endocrine disease. Despite being a deficiency of parathyroid hormone, the standard therapy is based on oral calcium and active vitamin D supplementation. This approach provides satisfactory management in most cases but may be inadequate for patients in the most complex spectrum of the disease. Other therapies are being explored, and among them, the use of recombinant human parathyroid hormone (PTH) has proved to decrease the requirements of calcium and active vitamin D to reach adequate therapeutic goals.

OBJECTIVE

We aimed to provide information on the effectiveness of the current recombinant parathyroid hormone analogs in the clinical management of difficult to control cases of hypoparathyroidism.

METHOD AND MATERIALS

We report our experience using teriparatide and PTH (1-84) through five complex cases of hypoparathyroidism of diverse etiologies. We describe each case and report the effectiveness of treatment in clinical practice.

RESULTS

Four patients with postsurgical hypoparathyroidism and one patient with autoimmune hypoparathyroidism, all of them with suboptimal control under the standard treatment with calcium and calcitriol supplements or calcium gluconate infusion, are presented. They were all started on teriparatide or PTH (1-84), and all of them showed a diminishment of symptoms and were able to maintain normocalcemia without parenteral calcium despite a reduction of oral treatment.

CONCLUSION

This article highlights the effectiveness and safety of hormonal replacement treatment in difficult to manage hypoparathyroidism and provides evidence which justifies its off-label prescription in the case of teriparatide. We consider that this treatment should be considered in cases in which standard treatment fails to reach adequate therapeutic goals.

Teriparatide Therapy in a 4-Month-Old With Severe Hypoparathyroidism

Teriparatide is a human parathyroid hormone analog approved for the treatment of osteoporosis in adult patients. Its use for hypocalcemia and hypoparathyroidism in the pediatric population is described through case reports and small case series; however, larger studies that demonstrate long-term efficacy and safety are limited. At our institution, a 4-month-old premature (gestational age: 32 weeks) infant with multiple congenital anomalies, functional athymia, and severe hypoparathyroidism and receiving calcitriol, vitamin D, and calcium carbonate supplementation was initiated on subcutaneous injection of teriparatide. During the course of treatment, her calcium carbonate, vitamin D, and calcitriol supplementation requirements substantially decreased. Teriparatide effectively increased serum ionized calcium concentrations and decreased serum phosphorus concentrations in the present case-study over a 6-month period. Teriparatide was well tolerated, and no evidence of hypercalcemia was observed throughout treatment.

Continuous Teriparatide Treatment in Chronic Hypoparathyroidism: A Case Report

Patient: Female, 29-year-old

Final Diagnosis: Chronic hypoparathyroidism

Symptoms: Muscle cramps • numbness • tingling in fingers

Medication: —

Clinical Procedure: —

Specialty: Endocrinology and Metabolic

Therapy with PTH 1-34 or calcitriol and calcium in diverse etiologies of hypoparathyroidism over 27 years at a single tertiary care center

OBJECTIVE

Hypoparathyroidism has heterogeneous genetic and acquired etiologies with a broad spectrum of severity. Herein we describe the clinical outcomes of the largest cohort of hypoparathyroid patients reported to date, who were followed over 27-years.

DESIGN

Pooled analysis of current and past studies describing the differential responses to PTH 1-34 injections vs conventional therapy among the varied hypoPT etiologies.

METHODS

192 participants (ages 2-74 years) with hypoparathyroidism who received either calcitriol and calcium or PTH 1-34 by subcutaneous injection.

RESULTS

Among the 4 main etiologic categories of hypoparathyroidism (autoimmune polyglandular failure type 1, activating mutation of the calcium receptor, surgical, and idiopathic hypoparathyroidism), we reveal significant differences in PTH 1-34 dose requirements, prevalence of nephrocalcinosis, biomarkers of mineral homeostasis, and pharmacodynamic profiles. Serum 1,25-dihydroxyvitamin D₃ increased significantly (P < 0.001) and 25-hydroxyvitamin D levels decreased during PTH 1-34 injections compared to calcitriol therapy (P < 0.01). Post-surgical patients achieved consistently lower urine calcium excretion over long-term PTH 1-34 therapy compared to conventional therapy (p < 0.001), but this was not achieved in the other etiologies. At study entry, patients had a high prevalence of renal insufficiency and nephrocalcinosis which were directly related to the duration of hypoparathyroidism (P < 0.03). Renal function remained stable during participation in our studies for both PTH 1-34 and conventional therapies.

CONCLUSIONS

We conclude that the effects and dose-response of PTH 1-34 treatment differ according to the etiology of hypoparathyroidism. Postsurgical hypoPT maintained mean serum calcium levels in the mid- to low-normal range while concurrently maintaining normal mean urine calcium during long-term twice-daily PTH 1-34 therapy.

Recombinant human parathyroid hormone (1-84) replacement therapy in a child with hypoparathyroidism

First line conventional therapy of hypoparathyroidism comprises oral calcium and active vitamin D analogues. This approach may fail to correct hypocalcemia and hyperphosphatemia caused by the absence of parathyroid hormone and carries the risk of long-term complications including ectopic calcifications and renal damage. Full-length recombinant human parathyroid hormone (rhPTH[1-84]) is approved for the treatment of hypoparathyroidism in adults refractory to conventional therapy. To date, there is no data in children. Here, we report the successful use of rhPTH(1-84) in a 5-year old girl with hypoparathyroidism and concomitant chronic diarrhea manifesting as part of the autoimmune polyglandular syndrome type 1. Prior to starting rhPTH(1-84), the patient had been on conventional and later on rhPTH(1-34) continuous pump therapy. Conventional therapy failed to meet serum and urinary calcium target levels, whilst the pump therapy wasn't well tolerated and posed handling difficulties. Dose optimization for rhPTH(1-84) was informed by serum ionized calcium, spot urinary calcium-to-creatinine ratio and 24-hour urinary calcium excretion. Twice-daily subcutaneous injections of rhPTH(1-84) with a total dose of 3.35 μg/kg/d was well-tolerated, raised serum ionized calcium to target range (1.05-1.15 mmol/L) and normalized serum phosphate levels. Urinary calcium excretion was slightly above the recommended limit of 4 mg/kg/24 h, but improved compared to conventional therapy, with no evidence of nephrocalcinosis. Twice-daily administration stabilized serum calcium and phosphate levels compared to once-daily injections. rhPTH(1-84) treatment was well tolerated and the girl did not manifest any acute clinical complications of hypoparathyroidism throughout the entire observation period. Our experience with this case indicates that rhPTH(1-84) may be a physiological hormone replacement for managing hypoparathyroidism in children.

Impact of periprocedural subcutaneous parathyroid hormone on control of hypocalcaemia in APS-1/APECED patients undergoing invasive procedures

CONTEXT

The monogenic disorder autoimmune polyendocrine syndrome type 1 (APS-1) or autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) manifests frequently with hypoparathyroidism, which requires treatment with oral supplementation with calcium and active vitamin D analogs. The majority of APS-1/APECED patients also suffer from intestinal malabsorption, which complicates the management of hypoparathyroidism and may lead to refractory severe hypocalcaemia. In such situations, reliance on intravenous calcium carries a high risk of nephrocalcinosis and renal damage.

METHODS

Here, we report our experience of periprocedural subcutaneous administration of recombinant human parathyroid hormone (rhPTH 1-34) in APS-1/APECED patients. Serum calcium was measured up to five times within the 36-hour period starting the evening before the scheduled procedure and ending the morning following the procedure.

RESULTS

Twenty-seven APS-1/APECED patients with hypoparathyroidism (aged 4-67 years) underwent 31 invasive gastrointestinal and/or pulmonary procedures. The patients received an average rhPTH1-34 dose of 9.6 ± 1.4 µg by subcutaneous injection. 92% of the adults and 54% of children in our cohort had evidence of nephrocalcinosis. Mean calcium levels remained stable and ranged from 2.06 to 2.17 mmol/L with minimal fluctuation. None of our patients experienced periprocedural adverse events connected with hypocalcaemia.

CONCLUSION

rhPTH 1-34 is an alternative to conventional therapy in patients with APS-1/APECED and hypoparathyroidism undergoing invasive procedures. Subcutaneous PTH1-34 given directly before and after procedures resulted in well-controlled serum calcium levels maintained in the low-normal range and avoided the need for intravenous calcium which may contribute to renal calcifications and tubular damage.

Intermittent Bi-Daily Sub-cutaneous Teriparatide Administration in Children With Hypoparathyroidism: A Single-Center Experience

Introduction: The use of teriparatide has been reported in children with hypoparathyroidism as an investigational physiologic replacement therapy. Methods: We aimed to retrospectively report our pediatric experience of bi-daily sub-cutaneous teriparatide. Results are presented as median (25th-75th quartile). As part of the routine follow-up of these patients with hypoparathyroidism, total calcium at H0 (i.e., just before injection) and H4 (i.e., 4 h after teriparatide injection) and other biomarker parameters were regularly assessed. Results: At a median age of 10.7 (8.1-12.6) years, an estimated glomerular filtration rate (eGFR) of 110 (95-118) mL/min/1.73 m², calcium levels of 1.87 (1.81-1.96) mmol/L and an age-standardized phosphate of 3.8 (2.5-4.9) SDS, teriparatide therapy was introduced in 10 patients at the dose of 1.1 (0.7-1.5) μg/kg/day (20 μg twice daily), with further adjustment depending on calcium levels. Six patients already displayed nephrocalcinosis. Severe side effects were reported in one child: two episodes of symptomatic hypocalcemia and one of iatrogenic hypercalcemia; one teenager displayed dysgueusia. Calcium levels at H0 did not significantly increase whilst calcium at H4 and phosphate levels significantly increased and decreased, respectively. After 12 months, eGFR, calcium and age-standardized phosphate levels were 108 (90-122) mL/min/1.73 m², 2.36 (2.23-2.48) mmol/L, 0.5 (-0.1 to 1.5), and 68 (63-74) nmol/L, respectively, with a significant decrease in phosphate levels (p = 0.01). Urinary calcium and calcium/creatinine ratio remained stable; no nephrolithiasis was observed but two moderate nephrocalcinosis appeared. Conclusion: Intermittent teriparatide therapy significantly improves calcium and phosphate control, without increasing calciuria. It appears to be safe and well-tolerated in children.

Rare diseases of phosphate and calcium metabolism: Crossing glances between nephrology and endocrinology

Rare diseases of phosphate/calcium metabolism correspond to a wide and heterogeneous spectrum of diseases. Recent knowledge in physiology and genetics has made it possible to better characterize them and to propose attractive therapeutic approaches based on the underlying pathophysiology. These diseases are often at the interface between nephrology and endocrinology. In this spirit of a multidisciplinary care, each specialty can bring its own critical point of view and its own specificities to improve patient care. The objective of this manuscript is to "read" with a nephrologist's point of view the main frameworks of diseases of phosphate/calcium metabolism, to illustrate the three crucial messages of nephro-protection sent to endocrinologists. First, calciuria must be interpreted both in absolute value (concentration hypercalciuria) and in ratio (flow hypercalciuria). Second, renal monitoring of therapies inducing hypercalciuria on kidneys with normal renal function (e.g. active vitamin D analogs or teriparatide) should be systematic. Last, hyperphosphatemia, often latent in hypoparathyroidism and pseudo-hypoparathyroidism, should be detected and at least benefit from dietary measures, in the context of Western diets rich in phosphate hidden in food additives.

Investigation and management of hypocalcaemia

Hypocalcaemia is a common clinical scenario in children with a range of aetiological causes. It will often present with common symptoms but may occasionally be identified in an asymptomatic child. An understanding of the physiological regulation of plasma calcium is important in understanding the potential cause of hypocalcaemia and its appropriate management. The age of presentation will influence the likely differential diagnosis. We have presented a stepwise approach to the investigation of hypocalcaemia dependent on the circulating serum parathyroid hormone level at the time of presentation. The acute and long-term management of the underlying condition is also reviewed.

Parathyroid Hormone Replacement versus Oral Calcium and Active Vitamin D Supplementation in Hypoparathyroidism: A Meta-analysis

OBJECTIVES

Chronic hypoparathyroidism is treated conventionally with active vitamin D and high doses of calcium. Recombinant human parathyroid hormone (PTH) replacement is an attractive option for treating patients with hypoparathyroidism since it can replace the physiological action of native PTH. The aim of our study was to perform a comprehensive evaluation of the effects of PTH replacement on calcium homeostasis, bone metabolism, and daily requirement of calcium and active vitamin D.

MATERIALS AND METHODS

Randomized controlled trials done in chronic hypoparathyroid patients were included in this meta-analysis. The PTH group included subjects receiving a subcutaneous injection of either PTH (1-84) or PTH (1-34) with oral calcium and/or active vitamin D. The control group included those receiving oral calcium and active vitamin D with/without subcutaneous placebo injection. The primary outcome of this meta-analysis was to compare serum calcium, 24-h urinary calcium, and severe adverse effects among PTH and control groups.

RESULTS

In this meta-analysis, we did not find any difference in serum calcium level between PTH and control groups [mean difference (MD) - 0.01; 95% confidence interval (CI) - 0.09, 0.06; P = 0.71]. Although there was a trend towards low 24-h urinary calcium in the PTH group, the difference was not statistically significant (MD - 1.43; 95% CI - 2.89, 0.03; P = 0.06). The incidence of serious adverse events was also similar in both groups (RR 1.35; 95% CI 0.58, 3.16; P = 0.49).

CONCLUSION

Both PTH and active vitamin D therapies are associated with comparable serum and urine calcium levels with a similar incidence of serious adverse events in patients with chronic hypoparathyroidism.

Teriparatide (rhPTH 1-34) treatment in the pediatric age: long-term efficacy and safety data in a cohort with genetic hypoparathyroidism

BACKGROUND

Hypoparathyroidism is characterized by the absence or inadequately low circulating concentrations of the parathyroid hormone, resulting in hypocalcemia, hyperphosphatemia, and elevated fractional excretion of calcium in the urine. The use of activated vitamin D analogs and calcium supplements represent conventional therapy. Subcutaneous recombinant human parathormone [rhPTH(1-34)] has been proposed as a substitutive treatment, even to avoid side effects of vitamin D and calcium.

OBJECTIVE

To assess the long-term safety and efficacy of rhPTH(1-34) in a pediatric cohort of patients with genetic hypoparathyroidism.

METHODS

The study is a 9.2-year self-controlled study of six pediatric patients (four males and two females, aged 9.4 ± 5.2) with DiGeorge, hypoparathyroidism-deafness-renal dysplasia (HDR) or autoimmune-candidiasis-polyendocrinopathy-ectodermal-dysplasia (APECED) syndrome, associated with autoimmune intestinal malabsorption in a patient. The presence of clinical signs of hypocalcemia and biochemical parameters, such as calcium, phosphate, alkaline phosphatase in the blood and calcium-creatinine ratio in urine, were compared during conventional treatment and rhPTH(1-34) (teriparatide, 12.5 μg twice daily).

RESULTS

The rhPTH(1-34) treatment allowed a reduction, although not always a complete suspension, of calcium supplementation and a slight reduction of calcitriol therapy. The number of tetanic episodes was reduced in four patients during the rhPTH(1-34) treatment. Mean blood calcium, alkaline phosphatase, and phosphate did not significantly change, while a significant reduction of the urinary calcium-to-creatinine ratio (0.55 ± 0.32 vs 0.16 ± 0.09, p = 0.03) was obtained. Renal ultrasound examination showed a worsening in three patients, while it did not change in the remaining three subjects during the follow-up.

CONCLUSIONS

In children with syndromic hypoparathyroidism presented here, replacement therapy with rhPTH(1-34) allowed to maintain adequate levels of the calcium and phosphate in the blood, normalize urinary calcium excretion, and reduce tetanic episodes. In patients with low compliance to conventional therapy or intestinal malabsorption, the use of rhPTH(1-34) could be considered, also to reduce the side effects of treatment with vitamin D and calcium.

Alternative treatment of resistant hypoparathyroidism by intermittent infusion of teriparatide using an insulin pump: A case report

Hypoparathyroidism usually responds to oral active vitamin D and calcium, but, although rare, some patients do not respond to this treatment. A 47-year-old Caucasian female presented to our medical unit with classical oral treatment-resistant hypocalcemia after thyroidectomy. Teriparatide was infused through the insulin pump with dosage set to 1 unit which equals to 2.5 μg of teriparatide. In conclusion, intermittent subcutaneous infusion of teriparatide using an insulin pump is a safe and effective treatment modality to ensure normocalcemic conditions in patients with classical treatment-resistant hypoparathyroidism. 39th Turkey Congress of Endocrinology and Metabolic Diseases, May 3-7, 2017, Antalya, Turkey.

Advances in the treatment of hypoparathyroidism with PTH 1-34

Hypoparathyroidism is a rare disorder of calcium metabolism which is treated with calcium and vitamin D analogs. Although conventional therapy effectively raises serum calcium, it bypasses the potent calcium reabsorption effects of PTH on the kidney which leads to hypercalciuria and an increased risk of nephrocalcinosis and renal insufficiency. Twenty-five years ago, we launched the first systematic investigation into synthetic human PTH 1-34 replacement therapy in both adults and children. These studies led to our current understanding of the complex nature of PTH 1-34 therapy and to the challenges we still face in our pursuit of a safe and effective physiologic replacement therapy for hypoparathyroidism. The normalization and minimal fluctuation of serum and urine calcium levels were the primary management goals. As the frequency of PTH 1-34 injections increased, the total daily dose required to normalize calcium homeostasis decreased and episodes of hypercalcemia and hypercalciuria diminished, producing a more physiologic biochemical profile. Twice-daily injections achieved simultaneous normalization of serum and urine calcium levels in many patients but the persistent elevation of bone markers and the difficulty in reducing urine calcium to normal levels in the more severe cases, suggested an alternative to PTH 1-34 injections was needed. The studies with PTH 1-34 delivered by insulin pump represent an important advance in the management of hypoparathyroidism. PTH 1-34 delivered by insulin pump normalized serum and urine calcium and markers of bone turnover. Additionally, pump delivery of PTH 1-34 produced stable magnesium values within the normal range and reduced magnesium excretion. Currently, PTH 1-34 delivery by pump is the only alternative to PTH injections that has been tested in both adults and children and proven to achieve a physiologic biochemical profile.