A Phase I Randomized Trial of Once-Daily Versus Twice-Daily Recombinant Human Parathyroid Hormone (1-84) for Hypoparathyroidism.

Recombinant human parathyroid hormone (1-84), rhPTH(1-84), is an approved adjunctive treatment to oral calcium and active vitamin D for adult patients with hypoparathyroidism; however, there is limited information on the effect of twice daily (BID) dosing of rhPTH(1-84). This was a phase I, open-label, randomized, crossover, multicenter study conducted in adult patients with chronic hypoparathyroidism. The primary objective was to assess the pharmacokinetic profile and pharmacodynamic effects of 1 day of treatment with rhPTH(1-84) administered subcutaneously at 25 µg BID, 50 µg BID, and 100 µg once daily (QD) with or without supplemental oral calcium. Safety and tolerability were evaluated as secondary objectives. In total, 33 patients with chronic hypoparathyroidism completed the study. Treatment with rhPTH(1-84), both BID and QD, over the short-term maintained serum calcium, lowered serum phosphorus, decreased urinary calcium excretion, and increased urinary phosphorus excretion. The decrease in urinary calcium excretion was numerically greater for BID than QD. Generally, baseline-adjusted pharmacokinetic parameters including area under the curve and maximum observed concentration increased with increasing rhPTH(1-84) dose, although this effect was not dose proportional. No new safety findings were observed. Our study revealed no differences thought to be clinically meaningful in pharmacokinetic or pharmacodynamic parameters with BID versus QD rhPTH(1-84) dosing. Future long-term studies are warranted to further elucidate the effects of alternative dosing strategies. © 2023 Takeda Development Center Americas, Inc and The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Safety of Inpatient Zoledronic Acid in the Immediate Postfracture Setting.

CONTEXT: Zoledronic acid (ZA) administered during the initial hospitalization for a fragility fracture improves the osteoporosis pharmacotherapy rate. Distinguishing the safety profile of inpatient ZA (IP-ZA) in this context is crucial if this approach is to be widely adopted. OBJECTIVE: To study the acute safety profile of IP-ZA. METHODS: An observational study of patients admitted to the Massachusetts General Hospital with fragility fractures who were eligible to receive IP-ZA. Patients were treated with or without IP-ZA. Acetaminophen, either as a single pre-ZA dose or standing multiple-doses-per-day regimen for 48 hours or longer after ZA infusion, was also administered along with protocolized vitamin D and calcium supplementation. Changes in body temperature, serum creatinine, and serum calcium were measured. RESULTS: A total of 285 consecutive patients, meeting inclusion and exclusion criteria, are included in this analysis; 204 patients received IP-ZA. IP-ZA treatment was associated with a transient mean rise of body temperature of 0.31 °C on the day following its administration. Temperatures above 38 °C were seen in 15% of patients in the IP-ZA group and 4% in the nontreated group. Standing multiple-doses-per-day but not a single pre-ZA dose of acetaminophen effectively prevented this temperature increase. IP-ZA did not affect serum creatinine levels. Mean levels of serum total calcium and albumin-corrected calcium decreased by 0.54 mg/dL and 0.40 mg/dL, respectively, at their nadirs (Day 5). No patient experienced symptomatic hypocalcemia. CONCLUSION: IP-ZA along with standing multiple-doses-per-day acetaminophen, administered to patients in the immediate postfracture period, is not associated with significant acute adverse effects.

Long-Term Safety and Efficacy of Recombinant Human Parathyroid Hormone (1-84) in Adults With Chronic Hypoparathyroidism.

Context: Chronic hypoparathyroidism is conventionally treated with oral calcium and active vitamin D to reach and maintain targeted serum calcium and phosphorus levels, but some patients remain inadequately controlled. Objective: To assess long-term safety and efficacy of recombinant human parathyroid hormone (1-84) (rhPTH(1-84)) treatment. Methods: This was an open-label extension study at 12 US centers. Adults (n = 49) with chronic hypoparathyroidism were included. The intervention was rhPTH(1-84) for 6 years. The main outcome measures were safety, biochemical measures, oral supplement doses, bone indices. Results: Thirty-eight patients (77.6%) completed the study. Throughout 72 months, mean albumin-adjusted serum calcium was within 2.00 to 2.25 mmol/L (8.0-9.0 mg/dL). At baseline, 65% of patients with measurements (n = 24/37) were hypercalciuric; of these, 54% (n = 13/24) were normocalciuric at month 72. Mean serum phosphorus declined from 1.6 ± 0.19 mmol/L at baseline (n = 49) to 1.3 ± 0.20 mmol/L at month 72 (n = 36). Mean estimated glomerular filtration rate was stable. rhPTH(1-84)-related adverse events were reported in 51.0% of patients (n = 25/49); all but 1 event were mild/moderate in severity. Mean oral calcium supplementation reduced by 45% ± 113.6% and calcitriol by 74% ± 39.3%. Bone turnover markers declined by month 32 to a plateau above pretreatment values; only aminoterminal propeptide of type 1 collagen remained outside the reference range. Mean bone mineral density z score fell at one-third radius and was stable at other sites. Conclusion: 6 years of rhPTH(1-84) treatment was associated with sustained improvements in biochemical parameters, a reduction in the percentage of patients with hypercalciuria, stable renal function, and decreased supplement requirements. rhPTH(1-84) was well tolerated; no new safety signals were identified.

Kidney Complications and Hospitalization in Patients With Chronic Hypoparathyroidism: A Cohort Study in Sweden.

CONTEXT: Kidney complications may be considerably higher in patients with chronic hypoparathyroidism (hypoPT) treated with activated vitamin D and calcium supplementation. OBJECTIVE: We aimed to investigate the risk of chronic kidney disease (CKD), urolithiasis, and hospitalization in patients with chronic hypoPT. METHODS: In this population-based cohort study in Sweden, national registries (Swedish National Patient Register, Swedish Prescribed Drug Register, and Total Population Register, 1997-2018) were used to identify patients with chronic hypoPT and controls matched by sex, age, and county of residence. We determined time to CKD and urolithiasis diagnosis, and incidence rates of hospitalization. RESULTS: A total of 1562 patients with chronic hypoPT without preexisting CKD and 15 620 controls were included. The risk of developing CKD was higher in patients with chronic hypoPT compared with controls (hazard ratio [HR] 4.45; 95% CI, 3.66-5.41). In people without prior urolithiasis (n = 1810 chronic hypoPT and n = 18 100 controls), the risk of developing urolithiasis was higher in patients with chronic hypoPT (HR 3.55; 95% CI, 2.84-4.44) compared with controls. Patients with chronic hypoPT had higher incidence rates for all-cause hospitalization (49.59; 95% CI, 48.50-50.70, per 100 person-years vs 28.43; 95% CI, 28.15-28.71, respectively) and for CKD (3.46; 95% CI, 3.18-3.76, per 100 person-years vs 0.72; 95% CI, 0.68-0.77, respectively), compared with controls. Men with hypoPT appear to have a higher risk of CKD than women. CONCLUSION: Patients with chronic hypoPT had an increased risk of CKD, urolithiasis, and hospitalization compared with controls.

Hypocalcemic disorders.

Calcium is vital for life, and extracellular calcium concentrations must constantly be maintained within a precise concentration range. Low serum calcium (hypocalcemia) occurs in conjunction with multiple disorders and can be life-threatening if severe. Symptoms of acute hypocalcemia include neuromuscular irritability, tetany, and seizures, which are rapidly resolved with intravenous administration of calcium gluconate. However, disorders that lead to chronic hypocalcemia often have more subtle manifestations. Hypoparathyroidism, characterized by impaired secretion of parathyroid hormone (PTH), a key regulatory hormone for maintaining calcium homeostasis, is a classic cause of chronic hypocalcemia. Disorders that disrupt the metabolism of vitamin D can also lead to chronic hypocalcemia, as vitamin D is responsible for increasing the gut absorption of dietary calcium. Treatment and management options for chronic hypocalcemia vary depending on the underlying disorder. For example, in patients with hypoparathyroidism, calcium and vitamin D supplementation must be carefully titrated to avoid symptoms of hypocalcemia while keeping serum calcium in the low-normal range to minimize hypercalciuria, which can lead to renal dysfunction. Management of chronic hypocalcemia requires knowledge of the factors that influence the complex regulatory axes of calcium homeostasis in a given disorder. This chapter discusses common and rare disorders of hypocalcemia, symptoms and workup, and management options including replacement of PTH in hypoparathyroidism.

Recombinant Human Parathyroid Hormone Effect on Health-Related Quality of Life in Adults With Chronic Hypoparathyroidism.

Context: Reduced health-related quality of life (HRQoL) is common in patients with hypoparathyroidism treated conventionally with calcium and active vitamin D supplements. Objective: To examine the effects of recombinant human parathyroid hormone [rhPTH(1-84)] on HRQoL as measured by the 36-Item Short-Form Health Survey (SF-36) during a multinational, randomized, placebo-controlled study. Patients: Adults (N = 122) with chronic hypoparathyroidism. Intervention(s): After an optimization period when calcium and/or active vitamin D supplements were adjusted to reach target serum calcium levels (8.0 to 9.0 mg/dL; 2.0 to 2.2 mmol/L), patients were randomly assigned to receive placebo (n = 39) or rhPTH(1-84) (n = 83) (starting dose, 50 µg/d, could be titrated up to 100 µg/d); supplement doses were adjusted to maintain target serum calcium levels. Main Outcome Measure(s): Change from baseline (postoptimization, at randomization) to week 24 in HRQoL as assessed by the SF-36. Results: Overall, the between-group differences were not statistically significant. However, in the rhPTH(1-84) group, there were significant improvements in the physical component summary score (P = 0.004), and in body pain (P < 0.05), general health (P < 0.05), and vitality (P < 0.001) domains as compared with baseline values. In the placebo group, there were no significant changes for any domains. The magnitude of change between 0 and 24 weeks in SF-36 scores was negatively correlated with baseline scores, such that patients with lower HRQoL at baseline were more likely to experience improvement in response to treatment. Conclusion: Treatment with rhPTH(1-84) may improve HRQoL in adults with hypoparathyroidism.

Hypoparathyroidism.

Hypoparathyroidism is a disease characterized by inadequately low circulating concentrations of parathyroid hormone (PTH) resulting in low calcium levels and increased phosphate levels in the blood. Symptoms of the disease result from increased neuromuscular irritability caused by hypocalcaemia and include tingling, muscle cramps and seizures. The most common cause of the disease is inadvertent removal of, or injury to, the parathyroid glands during neck surgery, followed by genetic, idiopathic and autoimmune aetiologies. Conventional treatment includes activated vitamin D and/or calcium supplements, but this treatment does not fully replace the functions of PTH and can lead to short-term problems (such as hypocalcaemia, hypercalcaemia and increased urinary calcium excretion) and long-term complications (which include nephrocalcinosis, kidney stones and brain calcifications). PTH replacement has emerged as a new treatment option. Clinical trials using human PTH(1-34) and PTH(1-84) showed that this treatment was safe and effective in studies lasting up to 6 years. Recombinant human PTH(1-84) has been approved in the United States and Europe for the management of hypoparathyroidism; however, its effect on long-term complications is still being evaluated. Clinical practice guidelines, which describe the consensus of experts in the field, have been published and recognize the need for more research to optimize care. In this Primer, we summarize current knowledge of the prevalence, pathophysiology, clinical presentation and management of hypoparathyroidism.

Safety and Efficacy of Recombinant Human Parathyroid Hormone in Adults With Hypoparathyroidism Randomly Assigned to Receive Fixed 25-µg or 50-µg Daily Doses.

PURPOSE: The present study examined the efficacy and safety of a lower rhPTH(1-84) dose. METHODS: RELAY was a dose-blinded, multicenter, 8-week study of patients with hypoparathyroidism randomized to fixed 25- or 50-µg/d doses of subcutaneous rhPTH(1-84). The primary end point was the percentage of patients at week 8 with supplement reductions in calcium to ≤500 mg/d and in calcitriol to ≤0.25 µg/d, while maintaining serum calcium levels between 1.875 mmol/L and the upper limit of normal. The secondary end point was the percentage of patients at week 8 with a ≥50% reduction in calcium and calcitriol doses, while maintaining serum calcium levels between 1.875 mmol/L and the upper limit of normal. FINDINGS: Forty-two patients were randomized (25-µg group, n = 19; 50-µg group, n = 23). At week 8, the primary end point was achieved by 4 (21%; 95% CI, 6%-46%) and 6 (26%; 95% CI, 10%-48%) of the patients receiving 25 and 50 µg/d of rhPTH(1-84), respectively. The secondary end point was achieved by 2 (11%; 95% CI, 1%-33%) and 6 (26%; 95% CI, 10%-48%) of the patients receiving 25 and 50 µg/d of rhPTH(1-84), respectively. Treatment-emergent adverse events were reported by 11 (58%) patients in the 25-µg group and 17 (74%) patients in the 50-µg group. IMPLICATIONS: Doses as low as 25 µg/d of rhPTH(1-84) are well tolerated and may be effective for a subset of patients. ClinicalTrials.gov identifier: NCT01268098.

Management of Hypoparathyroidism: Present and Future.

CONTEXT: Conventional management of hypoparathyroidism has focused upon maintaining the serum calcium with oral calcium and active vitamin D, often requiring high doses and giving rise to concerns about long-term consequences including renal and brain calcifications. Replacement therapy with PTH has recently become available. This paper summarizes the results of the findings and recommendations of the Working Group on Management of Hypoparathyroidism. EVIDENCE ACQUISITION: Contributing authors reviewed the literature regarding physiology, pathophysiology, and nutritional aspects of hypoparathyroidism, management of acute hypocalcemia, clinical aspects of chronic management, and replacement therapy of hypoparathyroidism with PTH peptides. PubMed and other literature search engines were utilized. EVIDENCE SYNTHESIS: Under normal circumstances, interactions between PTH and active vitamin D along with the dynamics of calcium and phosphorus absorption, renal tubular handing of those ions, and skeletal responsiveness help to maintain calcium homeostasis and skeletal health. In the absence of PTH, the gastrointestinal tract, kidneys, and skeleton are all affected, leading to hypocalcemia, hyperphosphatemia, reduced bone remodeling, and an inability to conserve filtered calcium. Acute hypocalcemia can be a medical emergency presenting with neuromuscular irritability. The recent availability of recombinant human PTH (1-84) has given hope that management of hypoparathyroidism with the missing hormone in this disorder will provide better control and reduced needs for calcium and vitamin D. CONCLUSIONS: Hypoparathyroidism is associated with abnormal calcium and skeletal homeostasis. Control with calcium and active vitamin D can be a challenge. The availability of PTH (1-84) replacement therapy may usher new opportunities for better control with reduced supplementation requirements.

Efficacy and safety of recombinant human parathyroid hormone (1-84) in hypoparathyroidism (REPLACE): a double-blind, placebo-controlled, randomised, phase 3 study.

BACKGROUND: Hypoparathyroidism results in impaired mineral homoeostasis, including hypocalcaemia and hyperphosphataemia. Treatment with high-dose oral calcium and active vitamin D does not provide adequate or consistent control of biochemical indices and can lead to serious long-term complications. We aimed to test the efficacy, safety, and tolerability of once-daily recombinant human parathyroid hormone 1-84 (rhPTH[1-84]) in adults with hypoparathyroidism. METHODS: In this double-blind, placebo-controlled, randomised phase 3 study (REPLACE), we recruited patients with hypoparathyroidism (≥ 18 months duration) aged 18-85 years from 33 sites in eight countries. After an optimisation period, during which calcium and active vitamin D doses were adjusted to achieve consistent albumin-corrected serum calcium, patients were randomly assigned (2:1) via an interactive voice response system to 50 µg per day of rhPTH(1-84) or placebo for 24 weeks. Active vitamin D and calcium were progressively reduced, while rhPTH(1-84) could be titrated up from 50 µg to 75 µg and then 100 µg (weeks 0-5). The primary endpoint was the proportion of patients at week 24 who achieved a 50% or greater reduction from baseline in their daily dose of oral calcium and active vitamin D while maintaining a serum calcium concentration greater than or the same as baseline concentrations and less than or equal to the upper limit of normal, analysed by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00732615. FINDINGS: Between June 23, 2009, and Feb 28, 2011, 134 eligible patients were recruited and randomly assigned to rhPTH(1-84) (n=90) or placebo (n=44). Six patients in the rhPTH(1-84) group and seven in the placebo group discontinued before study end. 48 (53%) patients in the rhPTH(1-84) group achieved the primary endpoint compared with one (2%) patient in the placebo group (percentage difference 51.1%, 95% CI 39.9-62.3; p<0.0001). The proportions of patients who had at least one adverse event were similar between groups (84 [93%] patients in the rhPTH[1-84] group vs 44 [100%] patients in the placebo group), with hypocalcaemia, muscle spasm, paraesthesias, headache, and nausea being the most common adverse events. The proportions of patients with serious adverse events were also similar between the rhPTH(1-84) group (ten [11%] patients) and the placebo group (four [9%] patients). INTERPRETATION: 50 µg, 75 µg, or 100 µg per day of rhPTH(1-84), administered subcutaneously in the outpatient setting, is efficacious and well tolerated as a PTH replacement therapy for patients with hypoparathyroidism.