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Cinacalcet for Fibroblast Growth Factor 23 (FGF23)-Mediated Hypophosphatemia (Hypophosphatemic Rickets)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01748812
Recruitment Status : Terminated
First Posted : December 13, 2012
Last Update Posted : July 5, 2018
Information provided by (Responsible Party):
National Institutes of Health Clinical Center (CC) ( National Institute of Dental and Craniofacial Research (NIDCR) )

Brief Summary:


  • Hypophosphatemia is a condition where a person has low levels of phosphorus in the blood. Low blood phosphorus can cause muscle and bone weakness (such as rickets) and teeth problems. One cause of the condition is having too much fibroblast growth factor 23 (FGF23). FGF23 is a hormone that causes the kidney to get rid of phosphorus in the urine. It can also prevent the body from making vitamin D, which helps the body absorb phosphorus in food.
  • Many people with low blood phosphorus take high doses of phosphorus and calcium medications. However, one side effect of these drugs is increased blood levels of parathyroid hormone (PTH). The drug cinacalcet can help lower PTH levels, which may decrease the amount of phosphorus lost in the urine and increase the phosphorus levels in the blood. Researchers want to see if cinacalcet can help blood phosphorus and decrease the amount of phosphorus supplements that people need to take.


- To see if cinacalcet can be a safe and effective treatment for people with low phosphorus conditions due to high FGF23.


- Individuals between 18 and 70 years of age who have different forms of hypophosphatemic rickets and tumor-induced hypophosphatemia


  • Participants will have up to 25 study visits over about 28 weeks.
  • Participants will be screened with a physical exam and medical history. Blood and urine samples will be collected.
  • Up to three more lab visits for blood and urine tests will be required before treatment. Imaging studies of the bones, spine, and kidneys will be performed.
  • Participants will have a 3-night hospital stay to start treatment. They will take cinacalcet once a day. Treatment will be monitored with frequent blood tests and imaging studies.
  • Participants will continue to take cinacalcet once a day for 3 weeks. They will have regular study visits to monitor the treatment.
  • There will be up to two other overnight hospital stays (1 to 3 nights) to adjust cinacalcet doses. The dose will increase until the maximum dose is reached, or side effects develop.
  • After the end of the cinacalcet study, participants will have several more followup visits to monitor the effects of treatment.

Condition or disease Intervention/treatment Phase
Osteomalacia Drug: Osteomalacia Phase 1

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 1 participants
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Open-label Dose-titration Study of the Tolerability and Efficacy of Cinacalcet to Treat Fibroblast Growth Factor 23 (FGF23)-Mediated Hypophosphatemia
Study Start Date : November 16, 2012
Actual Primary Completion Date : December 31, 2016
Actual Study Completion Date : December 31, 2016

Primary Outcome Measures :
  1. Evaluate the tolerability of cinacalcet in individuals with FGF23-mediated hypophosphatemia [ Time Frame: 4 years ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 70 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

    1. <TAB>Chronological age: 18-70 years
    2. <TAB>Diagnosis of a genetic form of FGF23-mediated hypophosphatemia:

      1. <TAB>X-linked hypophosphatemic rickets (XLH)
      2. <TAB>Autosomal dominant hypophosphatemic rickets (ADHR)
      3. <TAB>Autosomal recessive hypophosphatemic rickets (ARHR)

      Or, diagnosis of a non-genetic form of FGF23-mediated hypophosphatemia, i.e. tumor-induced osteomalacia (TIO)

    3. <TAB>Ability to understand and provide informed consent
    4. <TAB>Ability to complete the protocol scheduled assessments and medication regimen
    5. <TAB>Women of child-bearing potential (not surgically sterile via tubal ligation, bilateral oophorectomy or hysterectomy, or who are not postmenopausal for greater than or equal to 1 year) must agree to practice adequate contraception that may include, but is not limited to, abstinence, monogamous relationship with vasectomized partner, barrier methods such as condoms, diaphragms, spermicides, intrauterine devices, and licensed hormonal methods for the duration of the treatment portion of the study.


  1. <TAB>Chronic or recurrent hypocalcemia defined by a serum calcium < 8.4 mg/dL (2.1 mmol/L)
  2. <TAB>Tertiary hyperparathyroidism as evidenced by concurrent PTH and calcium levels above the upper limit of normal
  3. <TAB>History of parathyroid surgery and/or hypoparathyroidism
  4. <TAB>Hypercalciuria as defined as > 4 mg/kg/day (0.1 mmol/kg/day) on optimized conventional therapy (as determined during SOC optimization phase)
  5. <TAB>Moderate to severe hepatic insufficiency as defined by total bilirubin > 2 mg/dL and serum albumin < 3 g/dL and International Normalized Ratio (INR) >2 OR presence of ascites or hepatic encephalopathy.
  6. <TAB>A calculated eGFR < 50 mL/min/1.73 m(2), using the CKD-EPI equation
  7. <TAB>History of a non-febrile seizure disorder
  8. <TAB>History of a clinically significant cardiac arrhythmia
  9. <TAB>History of chronic gastrointestinal disease
  10. <TAB>Current therapy (at the time of informed consent) bisphosphonates, calcitonin, diuretics or medications that may have a significant drug interaction with cinacalcet
  11. <TAB>Known hypersensitivity to cinacalcet or any of its constituents
  12. <TAB>Positive pregnancy test or lactation
  13. <TAB>Use of another investigational agent (i.e., in the context of a clinical trial, use of an investigational product that may have impact on the study) within the last 3 months

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 identifier (NCT number): NCT01748812

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United States, Maryland
National Institutes of Health Clinical Center, 9000 Rockville Pike
Bethesda, Maryland, United States, 20892
Sponsors and Collaborators
National Institute of Dental and Craniofacial Research (NIDCR)
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Principal Investigator: Rachel I Gafni, M.D. National Institute of Dental and Craniofacial Research (NIDCR)
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Responsible Party: National Institute of Dental and Craniofacial Research (NIDCR) Identifier: NCT01748812    
Other Study ID Numbers: 130025
First Posted: December 13, 2012    Key Record Dates
Last Update Posted: July 5, 2018
Last Verified: July 7, 2015
Keywords provided by National Institutes of Health Clinical Center (CC) ( National Institute of Dental and Craniofacial Research (NIDCR) ):
Tumor Induced Osteomalacia
Hypophosphatemic Rickets
Additional relevant MeSH terms:
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Phosphorus Metabolism Disorders
Metabolic Diseases
Bone Diseases, Metabolic
Bone Diseases
Musculoskeletal Diseases
Calcium Metabolism Disorders
Vitamin D Deficiency
Deficiency Diseases
Nutrition Disorders