Recruiting
Early Phase 1

Observational Study

Sponsor:

Yale University

Code:

NCT03771105

Conditions

Hypophosphatemia

Rickets

Hypercalciuria

XLH

HHRH

Eligibility Criteria

Sex: All

Age: 13+

Healthy Volunteers: Not accepted

Interventions

phosphate

Study Details

Brief summary:

Determine the association between duration and dose of chronic conventional therapy with Pi and renal (nephrocalcinosis/nephrolithiasis), vascular (endothelial function), and cardiovascular function (echo- cardiography) in patients with hereditary hypophosphatemic rickets with hypercalciuria (HHRH) and patients with X-linked hypophosphatemia (XLH).

Conditions

Hypophosphatemia

Rickets

Hypercalciuria

XLH

HHRH

Study ID

NCT03771105

Start date

Jan 1, 2019

Status verified date

May, 2026

Completion date

Apr, 2028

Anticipated

Primary completion date

Apr, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 13+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Children above the age of 13 years
  • Younger and older adults with XLH and HHRH with confirmed NPT2c mutations affecting both copies of the NPT2c gene (HHRH) or one copy of the PHEX gene (XLH)
  • Be willing to provide access to prior medical records to determine eligibility including imaging, biochemical, medical, and surgical history data
  • Be willing and able to complete all aspects of the study
  • Be willing to adhere to the study visit schedule and comply with the assessments (in the opinion of the investigator).

Exclusion Criteria:

  • Subjects will be excluded, if they are children younger than age 13 years
  • Subjects that have other diseases likely to impact bone and mineral metabolism (e.g. renal, hepatic, gastrointestinal disorders, and malignancy),
  • Subjects that are currently pregnant,
  • Subjects that received medical therapy or developed any condition, which in the opinion of the investigator, could present a concern for either subject safety or difficulty with data interpretation.
  • Subjects will be excluded from Aim 2, if they are unable to tolerate supplemental phosphate.

Study Design

Enrollment

30 participants

Anticipated

Allocation

Non randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Patients with hereditary hypophosphatemic rickets with HHRH

Hereditary hypophosphatemic rickets with hypercalciuria (HHRH)

active comparator: Patients with X-linked Hypophosphatemia

Patients with X-linked hypophosphatemia

active comparator: 15 Patients with X-linked Hypophosphatemia

15 Patients with X-linked Hypophosphatemia that will receive phosphate treatment for 30 days.

active comparator: 15 Patients Hereditary hypophosphatemic rickets with HHRH

15 patients withHereditary hypophosphatemic rickets with hypercalciuria (HHRH) that will receive phosphate treatment for 30 days.

Interventions

phosphate

The target daily phosphate (Pi) intake is 3,500 mg/day (dietary intake plus our supplementation) for this study. Subjects will take a supplement of Pi (as KPhos Neutral 250 mg/tablet) to reach this target. Subjects will receive treatment for 30 days.

Primary outcome measure

  • Parathyroid Hormone (PTH) levels [ Time Frame: 30 days ]
  • Fibroblast Growth Factor 23 (FGF23) levels [ Time Frame: 30 days ]

Central Contacts and Locations

Central contacts

Clemens Bergwitz, MD

203-737-5450clemens.bergwitz@yale.edu

Locations

Yale University School of Medicine

Recruiting

New Haven, Connecticut, United States, 06511

Contacts

Clemens Bergwitz, M.D.

203-737-5450clemens.bergwitz@yale.edu

More Information

Sponsor

Yale University

Last update posted

May 27, 2026

Last verified

May, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Yale University on 2026-05-27.