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Intravenous Sodium Thiosulfate Reduces Vascular Calcification in Hemodialysis 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

The study focuses on Vascular Calcification, a condition where calcium builds up in the walls of blood vessels, making them stiff. The treatment being tested is an intravenous (IV) infusion of a medication known as sodium thiosulfate (code name STS). The medication will be given during routine hemodialysis, a procedure that cleans the blood of people whose kidneys no longer work well. The purpose of the study is to see whether a short course of this drug can lower the blood’s tendency to form calcium deposits.

Participants will attend several dialysis sessions; during some sessions the study drug will be added to the dialysis fluid, while other sessions will be done without it. Blood samples will be taken before and after each session to measure a test called T50, which indicates how quickly calcium particles start to form. The study will also look at tiny particles called CPP and a few other blood markers that reflect inflammation and bone metabolism, with simple explanations provided to participants. The whole participation period lasts a few weeks, and no additional procedures beyond the usual dialysis and blood draws are required.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

Step 1
Initial enrollment and baseline assessment
After joining the study, basic health information is recorded and a physical examination is performed.
Blood samples are taken to measure the baseline level of t50, which indicates how quickly calcium‑phosphate particles form in the blood.
Other laboratory tests are done to evaluate inflammation and bone metabolism, such as crp, il‑6, tnf‑α, p1np, ctx, and calcium.
Step 2
Control dialysis session without medication
The first hemodialysis session is performed without receiving any study drug.
Blood samples are drawn before the start of dialysis and again after the session to compare changes in t50 and other markers.
The results from this session serve as the control for later comparisons.
Step 3
First medication infusion session
During a scheduled hemodialysis session, a single dose of sodium thiosulfate is given.
The dose is 25 g of a 25 % solution, administered as an intravenous infusion throughout the dialysis treatment.
Blood samples are taken immediately before the infusion and after the dialysis session to assess changes in t50 and other laboratory values.
The patient is monitored for any immediate reactions, such as changes in blood pressure or discomfort at the infusion site.
Step 4
Second medication infusion session
A second hemodialysis session includes the same 25 g dose of sodium thiosulfate given by intravenous infusion.
Pre‑dialysis and post‑dialysis blood samples are collected to track the effect on t50 and related markers.
The patient continues to be observed for any side effects during and after the infusion.
Step 5
Third medication infusion session
A third hemodialysis session repeats the administration of 25 g of sodium thiosulfate via intravenous infusion.
Blood is drawn before the start of dialysis and after the session to provide the final set of measurements for the study.
Standard monitoring for safety continues throughout the procedure.
Step 6
Final follow‑up and study completion
After the last infusion session, a final review of all laboratory results is performed.
The patient may have a brief visit with the study team to discuss any remaining questions, but no further study medication is given.
All data are recorded, and the patient’s participation in the trial is considered complete.

Who can join the trial?

6 criteria

Adults who are 18 years old or older.
Receiving hemodialysis (a treatment that cleans the blood when the kidneys cannot) for at least 3 months.
Have not had a sudden or severe illness in the last 14 days.
Have a stable dialysis prescription (the same treatment plan) for at least 4 weeks.
Each dialysis session lasts between 3 and 5 hours.
Can give written informed consent (sign a form showing they understand and agree to join the study).

Who cannot join the trial?

9 criteria

Known intolerance to sodium thiosulfate: you have had a bad reaction or allergy to this medication before.
Significant metabolic acidosis at screening (Base excess < -5.0): your blood is too acidic, indicating a serious imbalance in your body’s chemistry.
Current participation in another interventional clinical study: you are already enrolled in a different research trial that involves a treatment or procedure.
Unstable cardiovascular disease within 90 days, including acute coronary syndrome (ACS) (a heart attack or similar event), stroke or transient ischemic attack (TIA) (a brief loss of brain blood flow), decompensated heart failure (worsening heart function), life‑threatening arrhythmia (dangerous irregular heartbeat), or unplanned coronary revascularization (unexpected procedure to restore blood flow to the heart).
Pregnancy or breastfeeding: you are pregnant or are feeding a baby.
Use of sodium thiosulfate within the previous 3 months: you have taken this medication in the last three months.
Elevated phosphate (>2 mmol/L): the level of phosphate (a mineral in your blood) is higher than normal.
Calciphylaxis: a rare condition where calcium builds up in small blood vessels, causing painful skin lesions.
Albumin‑corrected hypocalcemia < 2.1 mmol/L, or ionized calcium < 1.05 mmol/L at screening: your blood calcium level is too low, either after adjusting for albumin (a protein that carries calcium) or in its active form.

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Verified sites

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Rijnstate Ziekenhuis Stichting
Verified
Arnhem, The Netherlands
Stichting Radboud University Medical Center
Verified
Nijmegen, The Netherlands

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Investigated drugs

Sodium thiosulfate is given as an intravenous (IV) solution during a regular hemodialysis session. In this trial, the medicine is being tested to see if it can quickly lower the tendency of calcium‑phosphate particles in the blood to turn into solid deposits. By doing this, researchers hope the drug will help slow down or prevent the hardening of blood vessels (vascular calcification) that often occurs in people on dialysis. The treatment is administered directly into the bloodstream through the dialysis line, allowing it to mix with the blood as the dialysis machine cleans it.

Sodium Thiosulfate Pentahydrate

What is already known about the treatment

Sodium thiosulfate - This medication is given as a 25 % solution for intravenous infusion, usually mixed into the dialysis fluid during a hemodialysis session. It is an approved antidote for cyanide poisoning and is also used off‑label for treating calciphylaxis, while recent studies are exploring its use to slow vascular calcification. The drug works by delivering sulfide ions that bind calcium and form soluble complexes, helping to prevent calcium deposits and providing antioxidant protection. It is classified as a calcium‑binding agent and antioxidant antidote.

Investigated diseases

Vascular Calcification - A condition where calcium deposits build up in the walls of blood vessels, making them stiff and less flexible. It often starts as tiny calcium crystals that gradually enlarge and merge. Over time, the hardened vessels can narrow, reducing blood flow to organs. The process tends to progress silently, becoming more extensive with age or chronic kidney disease. As the calcification spreads, the vessels lose their ability to expand and contract normally.