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Findings from B.L. Clarke and Co-Researchers Provides New Data on Hypoparathyroidism [Pharmacokinetics and Pharmacodynamics of Subcutaneous...

July 2, 2014

Findings from B.L. Clarke and Co-Researchers Provides New Data on Hypoparathyroidism [Pharmacokinetics and Pharmacodynamics of Subcutaneous Recombinant Parathyroid Hormone (1-84) in Patients With Hypoparathyroidism: An Open-Label, Single-Dose, ...]

By a News Reporter-Staff News Editor at Biotech Week -- Investigators publish new report on Parathyroid Diseases and Conditions. According to news reporting from Bedminster, New Jersey, by NewsRx journalists, research stated, "Impaired mineral homeostasis affecting calcium, phosphate, and magnesium is a result of parathyroid hormone (PTH) deficiency in hypoparathyroidism. The current standard of treatment with active vitamin D and oral calcium does not control levels of these major minerals."

The news correspondents obtained a quote from the research, "Recombinant full-length human PTH 1-84 (rhPTH[1-84]) is being developed for the treatment of hypoparathyroidism. The goal of this study was to investigate the pharmacokinetics and pharmacodynamics of a single subcutaneous injection of rhPTH(1-84) in patients with hypoparathyroidism. This was an open-label, dose-escalating study of single subcutaneous administration of 50 mu g and then 100 mu g of rhPTH(1-84). Enrolled patients (age range, 25-85 years) had >= 12 months of diagnosed hypoparathyroidism defined according to biochemical evidence of hypocalcemia with concomitant low-serum intact PTH and were taking doses >= 1000 mg/d of oral calcium and >= 0.25 mu g/d of active vitamin D (oral calcitriol). The patient's prescribed dose of calcitriol was taken the day preceding but not on the day of or during the 24 hours after rhPTH(1-84) administration. Each patient received a single 50-mu g rhPTH(1-84) dose, had at least a 7-day washout interval, and then received a single 100-mu g rhPTH(1-84) dose. The following parameters were assessed: plasma PTH; serum and urine total calcium, magnesium, phosphate, and creatinine; and urine cyclic adenosine monophosphate. After administration of rhPTH(1-84) 50 mu g (n = 6) and 100 mu g (n = 7), the approximate t(1/2) was 2.5 to 3 hours. Plasma PTH levels increased rapidly, then declined gradually back to predose levels at similar to 12 hours. The median AUC was similar with calcitriol and rhPTH(1-84) for serum 1,25-dihydroxyvitamin D (calcitriol, 123-227 pg. h/mL; rhPTH[1-84], 101-276 pg. h/mL), calcium (calcitriol, 3.3-3.7 mg. h/dL; rhPTH[1-84], 3.3-7.6 mg. h/dL), and magnesium (calcitriol, 0.7-0.9 mg. h/dL; rhPTH[1-84], 1.3-2.8 mg. h/dL). In contrast, the median AUC for phosphate was strongly negative with rhPTH(1-84) (calcitriol, -1.0 to 0.8 mg. h/dL; rhPTH[1-84], -21.3 to -26.5 mg. h/dL). Compared with calcitriol, rhPTH(1-84) 50 mu g reduced 24-hour calcium excretion and calcium-to-creatinine ratios by 12% and 23%, respectively, and rhPTH(1-84) 100 mu g reduced them by 26% and 27%. There was little overall impact on urine magnesium levels. Compared with calcitriol, rhPTH(1-84) 50 mu g increased urinary phosphate excretion and phosphate-to-creatinine ratios by 53% and 54%, respectively, and rhPTH(1-84) 100 mu g increased them by 45% and 42%. Urine cyclic adenosine monophosphate to creatinine ratio increased with rhPTH(1-84) by 2.3-fold (50 mu g) and 4.4-fold (100 mu g) compared with calcitriol."

According to the news reporters, the research concluded: "PTH replacement therapy with rhPTH(1-84) regulated mineral homeostasis of calcium, magnesium, phosphate, and vitamin D metabolism toward normal in these study patients with hyp op arathyroidism."

For more information on this research see: Pharmacokinetics and Pharmacodynamics of Subcutaneous Recombinant Parathyroid Hormone (1-84) in Patients With Hypoparathyroidism: An Open-Label, Single-Dose, Phase I Study. Clinical Therapeutics, 2014;36(5):722-736. Clinical Therapeutics can be contacted at: Elsevier, 685 Route 202-206, Bridgewater, NJ 08807, USA. (Elsevier -; Clinical Therapeutics -

Our news journalists report that additional information may be obtained by contacting B.L. Clarke, NPS Pharmaceut Inc, Bedminster, NJ, United States. Additional authors for this research include J.K. Berg, J. Fox, J.A. Cyran and H. Lagast (see also Parathyroid Diseases and Conditions).

Keywords for this news article include: Pharmaceuticals, Drugs, Anions, Therapy, Chemicals, Chemistry, Bedminster, New Jersey, Calcitriol, Light Metals, United States, Endocrinology, Topical Agents, Peptide Hormones, Pharmacokinetics, Phosphoric Acids, Hypoparathyroidism, Magnesium Phosphate, Parathyroid Hormone, Dermatological Agents, Topical Antipsoriatics

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Source: Biotech Week

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