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Study on the Effectiveness of Cholecalciferol and Calcifediol in Treating Severe Vitamin D Deficiency in Patients

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying the treatment of severe vitamin D deficiency, a condition where the body has very low levels of vitamin D, which is essential for maintaining healthy bones and immune function. The study will compare two treatments: cholecalciferol (also known as vitamin D3) and calcifediol. Cholecalciferol is a form of vitamin D that is commonly used to increase vitamin D levels in the body, while calcifediol is a different form of vitamin D that is sometimes used for the same purpose.

The purpose of the study is to evaluate how effective and safe these treatments are in correcting vitamin D deficiency. Participants will be randomly assigned to receive either cholecalciferol or calcifediol. The study will last for a total of 12 weeks, with the main focus on the first 6 weeks. During this time, participants will take the assigned treatment orally, and their vitamin D levels will be monitored to see if they reach a healthy level. The study will also look at how well participants stick to the treatment plan and their satisfaction with the treatment.

Throughout the study, the safety of the treatments will be closely monitored by checking for any side effects. The goal is to determine which treatment is more effective in raising vitamin D levels to a healthy range and to ensure that the treatments are safe for participants. This information could help improve the management of severe vitamin D deficiency in the future.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    Upon joining the study, an initial assessment is conducted to confirm eligibility. This includes verifying age, vitamin D levels, and body mass index.

    Eligibility criteria require adults aged 18 years or older with severe vitamin D deficiency, defined as 25(OH)D levels of 12 ng/ml or lower.

  2. Step 2

    Randomization and treatment assignment

    Participants are randomly assigned to receive either cholecalciferol or calcifediol.

    Both medications are administered orally in the form of hard capsules.

  3. Step 3

    Treatment phase I

    The treatment lasts for 6 weeks. During this period, the primary goal is to correct vitamin D deficiency.

    The effectiveness of the treatment is evaluated by measuring the percentage of participants achieving 25(OH)D levels of 20 ng/ml or higher.

  4. Step 4

    Evaluation after phase I

    After 6 weeks, an evaluation is conducted to measure changes in vitamin D levels and other related parameters.

    Participants' satisfaction with the treatment is assessed using a questionnaire.

  5. Step 5

    Treatment phase II

    Participants continue the treatment for an additional 6 weeks, making a total of 12 weeks of treatment.

    The focus remains on achieving and maintaining adequate vitamin D levels.

  6. Step 6

    Final evaluation

    At the end of 12 weeks, a final evaluation is conducted to assess the overall effectiveness and safety of the treatment.

    The study measures the percentage of participants achieving the desired vitamin D levels and evaluates any changes in bone metabolism parameters.

  7. Step 7

    Safety and satisfaction assessment

    Throughout the study, the safety of the treatment is monitored by recording any adverse events.

    Participants' satisfaction and adherence to the treatment are evaluated at both 6 and 12 weeks.

Who can join the trial?

4 criteria

  • Adults of both genders who are **18 years or older**.
  • Patients with **severe vitamin D deficiency**, which means their vitamin D level is **12 ng/ml or lower**.
  • Patients with a **body mass index (BMI)** between **18.5 and 34.9 kg/m²**. BMI is a measure that uses height and weight to estimate body fat.
  • Patients who have **agreed in writing** to participate in the study.

Who cannot join the trial?

8 criteria

  • Patients with a history of **allergic reactions** to vitamin D or any of its components cannot participate. An allergic reaction is when your body reacts negatively to a substance, causing symptoms like rash or difficulty breathing.
  • Individuals who are currently taking medications that affect **vitamin D metabolism** are excluded. Metabolism refers to how your body processes and uses substances like vitamins.
  • Participants with **kidney disease** that affects vitamin D processing are not eligible. The kidneys are organs that help filter waste from the blood and manage vitamin levels.
  • People with **liver disease** that impacts vitamin D metabolism cannot join. The liver is an organ that helps process nutrients and detoxify the body.
  • Pregnant or breastfeeding women are not allowed to participate. This is to ensure the safety of both the mother and the baby.
  • Individuals with **hypercalcemia** are excluded. Hypercalcemia means having too much calcium in the blood, which can cause health problems.
  • Patients who have participated in another clinical trial within the last 30 days are not eligible. This is to avoid interference with the results of the study.
  • Anyone with a **malabsorption syndrome** is excluded. Malabsorption syndrome is a condition where the body cannot properly absorb nutrients from food.
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Investigated drugs

  • Cholecalciferol

    is a form of vitamin D that is used in this clinical trial to help increase vitamin D levels in people who have a severe deficiency. It is often referred to as vitamin D3 and is important for maintaining healthy bones and supporting the immune system.

  • Calcifediol

    is another form of vitamin D used in the trial. It is a more active form compared to cholecalciferol and is used to quickly increase vitamin D levels in the body. This medication helps in managing severe vitamin D deficiency by improving bone health and overall well-being.

What is already known about the treatment

  • Cholecalciferol

    Cholecalciferol is administered orally, typically in the form of capsules or tablets. It is currently being studied in clinical trials to evaluate its effectiveness in correcting severe vitamin D deficiency. The main therapeutic indication for cholecalciferol is to treat and prevent vitamin D deficiency, which is crucial for maintaining healthy bones and immune function. At the molecular level, cholecalciferol is converted in the liver to calcifediol, which is then further converted in the kidneys to its active form, calcitriol, helping to regulate calcium and phosphate levels in the body. It is classified as a vitamin D analog.

  • Calcifediol

    Calcifediol is also administered orally, often in capsule form. It is being compared to cholecalciferol in clinical trials to determine its efficacy in treating severe vitamin D deficiency. The primary therapeutic use of calcifediol is to manage vitamin D deficiency, which is essential for bone health and overall well-being. Calcifediol is a pre-hormone that is directly converted to the active form of vitamin D, calcitriol, in the kidneys, aiding in the regulation of calcium and phosphate metabolism. It belongs to the pharmacological class of vitamin D analogs.

Investigated diseases

Severe Vitamin D Deficiency – This condition occurs when the body has significantly lower levels of vitamin D than required for optimal health. Vitamin D is crucial for maintaining bone health, as it helps the body absorb calcium. A deficiency can lead to weakened bones, increasing the risk of fractures and bone disorders. It may also affect muscle function and the immune system. The deficiency progresses as the body continues to lack sufficient vitamin D, potentially leading to more severe health issues over time. Symptoms can include bone pain, muscle weakness, and fatigue.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-514528-17-00Protocol codeRES-6128-C1Estimated enrolment120 patientsSponsorItf Research Pharma S.L.

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