Calcitriol Monotherapy for X-Linked Hypophosphatemia

NCT ID: NCT03748966

Last Updated: 2025-10-01

Basic Information

• Recruitment Status: ACTIVE_NOT_RECRUITING
• Clinical Phase: EARLY_PHASE1
• Total Enrollment: 20 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2019-03-28
• Study Completion Date: 2026-05-31

Brief Summary

Children and adults with XLH recruited will be treated with calcitriol alone (without phosphate supplementation) for one year, during which the calcitriol dose will be escalated during the first 3 months of therapy. The investigators hypothesize that treatment of adults and children with XLH alone will improve serum phosphate levels and skeletal mineralization without causing an increase in kidney calcifications. The study will also examine if calcitriol therapy will improve growth in children.

Conditions

X-linked Hypophosphatemia; Hypophosphatemic Rickets; Hypophosphatemic Rickets, X-Linked Dominant

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

Adults with XLH

Adults with X-linked hypophosphatemia will be treated with optimized doses of calcitriol (without phosphate supplementation) for one year

Group Type: EXPERIMENTAL

Calcitriol

Intervention Type: DRUG

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.

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

Group Type: EXPERIMENTAL

Calcitriol

Intervention Type: DRUG

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.

Interventions

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.

Intervention Type: DRUG

Other Intervention Names

1,25 dihydroxyvitamin D

Eligibility Criteria

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.

• Minimum Eligible Age: 3 Years
• Maximum Eligible Age: 70 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)

NIH

Sponsor Role: collaborator

Massachusetts General Hospital

OTHER

Sponsor Role: lead

Responsible Party

Eva Liu

Assistant Professor of Medicine

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Eva Liu, MD

Role: PRINCIPAL_INVESTIGATOR

Massachusetts General Hospital and Brigham and Women's Hospital

Locations

Massachusetts General Hospital

Boston, Massachusetts, United States

Countries

United States

References

Liu ES, Martins JS, Raimann A, Chae BT, Brooks DJ, Jorgetti V, Bouxsein ML, Demay MB. 1,25-Dihydroxyvitamin D Alone Improves Skeletal Growth, Microarchitecture, and Strength in a Murine Model of XLH, Despite Enhanced FGF23 Expression. J Bone Miner Res. 2016 May;31(5):929-39. doi: 10.1002/jbmr.2783. Epub 2016 Feb 2.

Reference Type: BACKGROUND

PMID: 26751835 (View on PubMed)

Other Identifiers

2016P001000

Identifier Type: -

Identifier Source: org_study_id