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Effect of Cinacalcet on Parathyroid Hormone Secretion in Children and Adolescents With Hypophosphatemic Rickets

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ClinicalTrials.gov Identifier: NCT00195936
Recruitment Status : Unknown
Verified August 2005 by Children's Mercy Hospital Kansas City.
Recruitment status was:  Recruiting
First Posted : September 20, 2005
Last Update Posted : October 23, 2007
Information provided by:

Study Description
Brief Summary:
This study will measure the effect of cinacalcet (Sensipar) on parathyroid hormone (PTH) secretion in children and adolescents with hypophosphatemic rickets (XLH). The investigators are seeking evidence that patients with XLH may benefit from treatment with cinacalcet by achieving better control of PTH secretion.

Condition or disease Intervention/treatment Phase
Hypophosphatemic Rickets, X-Linked Dominant Drug: Cinacalcet Phase 1

Detailed Description:

X-linked hypophosphatemic rickets (XLH) is an X-linked dominant genetic disorder. Common findings are low serum phosphate and inadequate 1,25(OH)2 vitamin D production. It is generally believed that the primary defect in XLH is impaired renal tubular transport of phosphate coupled with abnormal regulation of the enzyme responsible for the 1-alfa hydroxylation of 25(OH) vitamin D. The current treatment of children with XLH is large oral doses of phosphate and 1,25-dihydroxyvitamin D. There are two common side effects to this treatment; nephrocalcinosis and secondary hyperparathyroidism (HPT). The latter at times may cause hypertension, hypercalcemia, and permanent renal damage. The complication of secondary hyperparathyroidism is seen in 20% of the patients. The release of PTH from the glands into the circulation is tightly regulated by serum calcium concentration. The glands "read" serum calcium concentration via Ca sensing receptors (CaR) which are located at the surface of the glands. Calcimimetics are compounds that allosterically modulate the CaR, thereby enhancing its sensitivity to circulating serum calcium concentrations and consequently decreasing PTH secretion. When used in primary HPT, they rapidly reduce PTH level and normalize serum calcium concentration.

Cinacalcet is a calcimimetic agent recently approved by the FDA for treating hypercalcemia in patients with parathyroid carcinoma and secondary HPT in patients with chronic renal disease. Cinacalcet was found to be effective in decreasing both PTH level and the calcium X phosphorous ion product in dialysis patients.

The goal of our proposed acute study is to see whether concomitant administration of Cinacalcet and phosphate, to patients with XLH, will block completely or partially secretion of PTH (day 2), expected to be seen following administration of phosphate alone (day 1). We will also monitor serum phosphate, total calcium, and ionized calcium concentration to learn to what extent, if any, blockage of PTH secretion affects mineral homeostasis under this condition.

If found to be effective in blocking PTH secretion, Cinacalcet will become a candidate for a long-term study in children with XLH to protect them from developing secondary hyperparathyroidism.

Study Design

Study Type : Interventional  (Clinical Trial)
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Effect of Calcimimetic (Cinacalcet) on Phosphate-Induced Hyperparathyroidism in Children With Hypophosphatemic Rickets
Study Start Date : June 2005

Arms and Interventions

Outcome Measures

Primary Outcome Measures :
  1. The primary outcome will be the effect of cinacalcet on serum PTH. [ Time Frame: PTH will be measured at time 0 and then every 30 minutes for 4 hours after receiving the medications ]

Secondary Outcome Measures :
  1. Secondary outcome will be the effect of the calcimimetic on mineral homeostasis; ionized calcium, total calcium, and phosphate will be measured. [ Time Frame: At time 0 and then every 30 minutes for 4 hours after receiving the medications ]

Eligibility Criteria

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Ages Eligible for Study:   5 Years and older   (Child, Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Established patients with XLH
  • Age 5 years old and above
  • Normal serum calcium and creatinine concentrations

Exclusion Criteria:

  • Patients with hypersensitivity to any component(s) of cinacalcet
  • Hypocalcaemia
  • Elevated serum creatinine
Contacts and Locations

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00195936

Contact: Rachel Levy-Olomucki, MD 816-234-3010 rlevy@cmh.edu

United States, Missouri
Section of Pediatric Nephrology, Children's Mercy Hospitals and Clinics Recruiting
Kansas City, Missouri, United States, 64108
Principal Investigator: Rachel Levy-Olomucki, MD         
Sponsors and Collaborators
Children's Mercy Hospital Kansas City
Principal Investigator: Rachel Levy-Olomucki, MD Section of Pediatric Nephrology, Children's Mercy Hospitals and Clinics
More Information

ClinicalTrials.gov Identifier: NCT00195936     History of Changes
Other Study ID Numbers: 05 02-027
First Posted: September 20, 2005    Key Record Dates
Last Update Posted: October 23, 2007
Last Verified: August 2005

Keywords provided by Children's Mercy Hospital Kansas City:
children and adolescents with hypophosphatemic rickets (XLH)

Additional relevant MeSH terms:
Rickets, Hypophosphatemic
Familial Hypophosphatemic Rickets
Bone Diseases, Metabolic
Bone Diseases
Musculoskeletal Diseases
Metabolic Diseases
Calcium Metabolism Disorders
Vitamin D Deficiency
Deficiency Diseases
Nutrition Disorders
Phosphorus Metabolism Disorders
Hypophosphatemia, Familial
Renal Tubular Transport, Inborn Errors
Kidney Diseases
Urologic Diseases
Metal Metabolism, Inborn Errors
Metabolism, Inborn Errors
Genetic Diseases, Inborn
Cinacalcet Hydrochloride
Calcimimetic Agents
Hormone Antagonists
Hormones, Hormone Substitutes, and Hormone Antagonists
Physiological Effects of Drugs