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Completed

NCT Number: NCT03104855

Clearance of 25-hydroxyvitamin D in Cystic Fibrosis

The goal of this study is to define 25(OH)D3 catabolism in CF patients using gold standard pharmacokinetics studies. Specifically, the investigators will evaluate the metabolic clearance of 25(OH)D3 among participants with CF and matched control subjects. The goal of this work is to provide the first comprehensive characterization of vitamin D metabolism in CF patients and promote novel hypotheses for subsequent studies.

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Key information

Conditions

Cystic Fibrosis Congenital, Hereditary, and Neonatal Diseases and Abnormalities Digestive System Diseases Genetic Diseases, Inborn Infant, Newborn, Diseases Lung Diseases Pancreatic Diseases Respiratory Tract Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 1

Primary location

University of Washington

Seattle, Washington, 98104, United States

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age ≥ 18 years
  • Serum total 25(OH)D 10-50 ng/mL
  • Diagnosis of cystic fibrosis in accordance with CF Foundation Guidelines; OR, normal CONTROL

Exclusion criteria

  • Primary hyperparathyroidism
  • Gastric bypass
  • Tuberculosis or sarcoidosis
  • Current pregnancy
  • Child-Pugh Class B or C cirrhosis (i.e. cirrhosis with ascites, hepatic encephalopathy, bilirubin >=2 mg/dL, serum albumin <=3.5 g/dL, or PT >= 4 seconds)
  • History of kidney transplantation or end stage renal disease treated with dialysis
  • Use of vitamin D3 or vitamin D2 supplements exceeding a mean daily dose of 400 IU, within 3 months (wash-out allowed)
  • Use of 1,25(OH)2D3 or an analogue, calcimimetics, or medications known to induce CYP24A1 within 4 weeks (wash-out allowed)
  • Serum calcium > 10.1 mg/dL
  • Hemoglobin < 9 g/dL

Treatment and study plan

D6-25-hydroxyvitamin D3

Drug

intravenous administration of stable isotope-labeled D6-25(OH)D3

Primary outcomes

  1. Metabolic Clearance of D6-25(OH)D3

    Time frame: 8 weeks

    Metabolic clearance is calculated as the administered dose of 25(OH)D3 divided by the area under the plasma concentration-time curve (AUC). AUC is calculated using the linear trapezoidal method.

Secondary outcomes

  1. AUC of D6-25(OH)D3

    Time frame: 8 weeks

    AUC is calculated using the linear trapezoidal method.

  2. Terminal Half-life of D6-25(OH)D3

    Time frame: 8 weeks

    Terminal half-life is equal to ln2/k, where k is the slope of the terminal regression line estimated using ≥3 plasma concentrations.

  3. Volume of Distribution of D6-25(OH)D3

    Time frame: 8 weeks

    Volume of distribution in the central compartment is calculated as dose/C0, where dose is the administered dose of 25(OH)D3 and C0 is the initial (estimated) concentration of drug in plasma.

Other outcomes

  1. Metabolic Formation Clearance of D6-25(OH)D3 Metabolites

    Time frame: 8 weeks

    Metabolic formation clearance is calculated as the daughter metabolite plasma AUC divided by the AUC of D6-25(OH)D3 (metabolite/parent AUC ratio). AUC is calculated using the linear trapezoidal method.

  2. Serum Concentration of Calcium

    Time frame: 7 days

    Change in the serum concentration of calcium from baseline to 7 days after 25(OH)D3

  3. Serum Concentration of Creatinine

    Time frame: 7 days

    Change in the serum concentration of creatinine from baseline to 7 days after 25(OH)D3

  4. Serum Concentration of AST

    Time frame: 7 days

    Change in the serum concentration of AST from baseline to 7 days after 25(OH)D3

  5. Serum Concentration of ALT

    Time frame: 7 days

    Change in the serum concentration of ALT from baseline to 7 days after 25(OH)D3

Sponsors and collaborators

Lead sponsor

University of Washington

Other

Collaborators

  • National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Registry information

Acronym: CF

Important dates

Study start
2017
Primary completion
2018
Study completion
2023
First posted
Apr 7, 2017
Registry last updated
Oct 12, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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