Using Different Doses of Active Vitamin D Combined With Neutral Phosphate in Children With X-linked Hypophosphatemia

Chinese Academy of Medical Sciences & Peking Union Medical College

Status and phase: Unknown; Phase 4

Conditions: X-linked Hypophosphatemia

Treatments: Drug: Calcitriol

Study type: Interventional

Funder types: Other

Identifiers

NCT03820518

JS-1824

Details and patient eligibility

About

X-linked hypophosphatemia (XLH) is the most common form of heritable rickets. Current treatments include active vitamin D metabolites (e.g. calcitriol) and phosphate salts. There is no consistent weight-based dosing of calcitriol and phosphate now. The primary objective of this study is to establish the efficacy of different dose of calcitriol combined with neutral phosphate in children with XLH.

Enrollment: 100 estimated patients

Sex: All

Ages: 1 to 12 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Male or female, aged 1-12 years, inclusive
• Diagnosis of XLH by clinical features: serum phosphorus level < 2.5 mg/dl; ALP?; RSS total score ≥2; bowed legs; short stature; family history with appropriate X-linked inheritance
• Meet at least one of the following: confirmed Phosphate regulating gene with homology to endopeptidases located on the X chromosome (PHEX) mutation in the participant, or serum FGF23 level >30 pg/ml (Kainos assay)
• Willing to participate the study, and provide an informed consent
• Able to complete all aspects of study and adhere to the visit schedule

Exclusion criteria

• Use of growth hormone within 12 months before first visit
• Height >50 percentile for age and sex specific data
• Presence of nephrocalcinosis or nephrolithiasis
• Serum intact parathyroid hormone level>170 pg/ml
• Plan to receive orthopaedic surgery in 12 months
• Poor compliance
• Use of gonadotropin-releasing hormone therapy right now
• Use of aluminium hydroxide, steroid, acetazolamide or thiazide drugs within 7 days before first visit
• Not be fit to participant in the study, by the judgement of investigators

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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100 participants in 2 patient groups

High-dose

Experimental group

Description:

Receiving 60 ng/kg/day of calcitriol and 30 mg/kg/day of elemental phosphorus.

Treatment:

Drug: Calcitriol

Low-dose

Experimental group

Description:

Receiving 20 ng/kg/day of calcitriol and 30 mg/kg/day of elemental phosphorus.

Treatment:

Drug: Calcitriol