Calcitriol Monotherapy for X-Linked Hypophosphatemia
![]() |
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. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. |
ClinicalTrials.gov Identifier: NCT03748966 |
Recruitment Status :
Recruiting
First Posted : November 21, 2018
Last Update Posted : March 31, 2022
|
- Study Details
- Tabular View
- No Results Posted
- Disclaimer
- How to Read a Study Record
Condition or disease | Intervention/treatment | Phase |
---|---|---|
X-linked Hypophosphatemia Hypophosphatemic Rickets Hypophosphatemic Rickets, X-Linked Dominant | Drug: Calcitriol | Early Phase 1 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 20 participants |
Allocation: | Non-Randomized |
Intervention Model: | Parallel Assignment |
Intervention Model Description: | Adults or children (age 3-17) with X-linked hypophosphatemia (XLH) will be enrolled the study. All research subjects will be treated with optimized doses of calcitriol alone (without phosphate supplementation) for one year. |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | Calcitriol Monotherapy for X-Linked Hypophosphatemia: Effects on Mineral Ions, Growth and Skeletal Parameters |
Actual Study Start Date : | March 28, 2019 |
Estimated Primary Completion Date : | March 2023 |
Estimated Study Completion Date : | March 2024 |

Arm | Intervention/treatment |
---|---|
Experimental: Adults with XLH
Adults with X-linked hypophosphatemia will be treated with optimized doses of calcitriol (without phosphate supplementation) for one year
|
Drug: Calcitriol
Adults and children (age 3-17) with X-linked hypophosphatemia will be treated with calcitriol therapy without phosphate supplementation. Doses of calcitriol will be escalated and optimized in the first three months of the study. Calcitriol is an oral medication taken once a day.
Other Name: 1,25 dihydroxyvitamin D |
Experimental: Children with XLH
Children (age 3-17) with X-linked hypophosphatemia will be treated with optimized doses of calcitriol (without phosphate supplementation) for one year
|
Drug: Calcitriol
Adults and children (age 3-17) with X-linked hypophosphatemia will be treated with calcitriol therapy without phosphate supplementation. Doses of calcitriol will be escalated and optimized in the first three months of the study. Calcitriol is an oral medication taken once a day.
Other Name: 1,25 dihydroxyvitamin D |
- Change from baseline in serum phosphate in adults and children with XLH [ Time Frame: up to 12 months ]
- Change from baseline in TmP/GFR in adults and children with XLH [ Time Frame: up to 12 months ]a measure of kidney resorption of phosphate
- Rickets score for children with XLH [ Time Frame: up to 12 months ]a score of rickets severity determined by reading x-rays of wrists and knees (10 point Thacher score with 0 being normal and 10 being severe)
- Change from baseline in nephrocalcinosis grade [ Time Frame: up to 12 months ]determine if there is change in amount of calcifications in the kidneys: graded from grade 0 (normal) to grade IV (stone formation, solitary focus of echos at the tip of the renal pyramid)
- Growth in children with XLH [ Time Frame: up to 12 months ]Z-score of growth

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 3 Years to 70 Years (Child, Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Clinical diagnosis of XLH with family history excluding male-to-male transmission, or positive genotype for PHEX mutation
- Serum PTH levels less than 1.5x the upper limit of normal
- Serum calcium levels less than 10.0 mg/dl
- eGFR >= 60 mL/min/1.73m2
- 25(OH) vitamin D level >= 20 ng/dL
Exclusion Criteria:
- Known allergy to calcitriol
- Pregnancy or breast feeding
- Use of skeletally active agents such as bisphosphonates, teriparatide, SERMS, hormone replacement therapy and progesterone-only contraceptive agents (combination oral contraceptive use in premenopausal women is not an exclusion criterion).
- Unwilling or unable to stop therapy with calcitriol and phosphate therapy for two weeks prior to study
- Therapy with cinacalcet within the past two weeks
- Current use of growth hormone therapy
- Use of diuretics or medications that alter renal handling of mineral ions.
- Use of glucocorticoids for more than 14 days in the past 12 months with the exception of inhaled agents.
- History of malignancy except basal and squamous cell carcinoma of the skin.
- Significant history of psychiatric disease per DSM-5.
- Substance use disorder per DSM-5.
- Significant cardiopulmonary disease (unstable CAD or stage D ACC/AHA heart failure).
- Absence of laboratory values for serum calcium, phosphate and creatinine in the 24 months prior to enrollment.

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): NCT03748966
Contact: Eva S Liu, MD | 16175255412 | esliu@bwh.harvard.edu | |
Contact: Marie Demay, MD | 16177263273 | demay@helix.mgh.harvard.edu |
United States, Massachusetts | |
Massachusetts General Hospital | Recruiting |
Boston, Massachusetts, United States, 02114 | |
Contact: Eva Liu, MD 617-525-5412 esliu@bwh.harvard.edu | |
Contact: Marie Demay, MD 6177263273 demay@helix.mgh.harvard.edu |
Principal Investigator: | Eva Liu, MD | Massachusetts General Hospital and Brigham and Women's Hospital |
Responsible Party: | Eva Liu, Assistant Professor of Medicine, Massachusetts General Hospital |
ClinicalTrials.gov Identifier: | NCT03748966 |
Other Study ID Numbers: |
2016P001000 |
First Posted: | November 21, 2018 Key Record Dates |
Last Update Posted: | March 31, 2022 |
Last Verified: | March 2022 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | No |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
Product Manufactured in and Exported from the U.S.: | No |
XLH calcitriol x-linked hypophosphatemia rickets 1,25 dihydroxyvitamin D |
bone disorder rare bone disease vitamin D hypophosphatemic rickets |
Rickets Familial Hypophosphatemic Rickets Rickets, Hypophosphatemic Hypophosphatemia Phosphorus Metabolism Disorders Metabolic Diseases Bone Diseases, Metabolic Bone Diseases Musculoskeletal Diseases Calcium Metabolism Disorders Vitamin D Deficiency Avitaminosis Deficiency Diseases Malnutrition Nutrition Disorders |
Hypophosphatemia, Familial Renal Tubular Transport, Inborn Errors Kidney Diseases Urologic Diseases Metal Metabolism, Inborn Errors Metabolism, Inborn Errors Genetic Diseases, Inborn Calcitriol Dihydroxycholecalciferols Calcium-Regulating Hormones and Agents Physiological Effects of Drugs Calcium Channel Agonists Membrane Transport Modulators Molecular Mechanisms of Pharmacological Action Vasoconstrictor Agents |