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This trial is complete. It is no longer accepting participants. Results may be available on ClinicalTrials.gov.

NCT03748966

NCT03748966
Completed Early Phase 1

Who may be able to join

Who might be able to join this trial:

  • You have been diagnosed with XLH (X-linked hypophosphatemia), confirmed either by a family history where no father passed it to a son, or by a genetic test showing a PHEX gene mutation
  • Your parathyroid hormone (PTH) blood level is below 1.5 times the upper limit of the normal range (confirm with trial site)
  • Your blood calcium level is below 10.0 mg/dl
  • Your kidneys are working at a reasonable level, with a filtering rate (eGFR) of 60 or above
  • Your vitamin D level (specifically 25(OH) vitamin D) is at least 20 ng/dL

Who may not be able to join:

  • You have a known allergy to calcitriol (a form of vitamin D)
  • You are currently pregnant or breastfeeding
  • You are taking certain bone-affecting medications such as bisphosphonates, teriparatide, SERMs, hormone replacement therapy, or progesterone-only contraceptives (note: combination birth control pills are generally allowed — confirm with trial site)
  • You are unwilling or unable to stop taking calcitriol and phosphate treatments for two weeks before the study begins
  • You have taken cinacalcet within the past two weeks
  • You are currently using growth hormone therapy
  • You are taking water pills (diuretics) or other medicines that affect how your kidneys handle minerals
  • You have taken steroid medications (such as prednisone) by mouth or injection for more than 14 days in the past year (inhaled steroids are generally allowed — confirm with trial site)
  • You have a history of cancer, except for certain common skin cancers (basal cell or squamous cell)
  • You have a significant psychiatric condition as defined by DSM-5 guidelines (confirm with trial site)
  • You have a substance use disorder as defined by DSM-5 guidelines (confirm with trial site)
  • You have serious heart or lung disease, such as unstable coronary artery disease or advanced heart failure
  • You do not have blood test results for calcium, phosphate, and creatinine from within the past 24 months

Important: Always verify eligibility with the trial site directly before applying.

Based on publicly available eligibility criteria from ClinicalTrials.gov. Verify directly with the trial site before acting. This is not medical advice.

Early Phase 1: approximately ~10% of drugs entering this phase reach regulatory approval, based on published industry-wide historical data. This is not specific to this trial.

Trial details

Status
Completed
Phase
Early Phase 1
Sponsor
Massachusetts General Hospital
Registry
clinicaltrials_gov
Start date
28 March 2019
Est. completion
1 March 2025

Where this trial is recruiting

🇺🇸 United States

Primary endpoints

Change in Serum Phosphate in Adults and Children With XLH Between Baseline and 12 Months; Change From Baseline in TmP/GFR in Adults and Children With XLH; Rickets Score for Children With XLH; Change From Baseline in Nephrocalcinosis Grade

Can't join this trial?

Expanded access pathways

If this trial is not available to you, other access pathways may exist. In Australia, the TGA Special Access Scheme allows access to unapproved therapeutic goods for individual patients.

TGA Special Access Scheme information

Find other recruiting trials on ClinicalTrials.gov

Data last synced from ClinicalTrials.gov: 30 June 2026. Trial status can change. Always verify current status directly with the trial site before making any decision.

View original record on ClinicalTrials.gov