A Phase 3 interventional study of Colchicine 0.5 MG Oral Tablet and Placebo in Venous Thrombosis Deep (Limbs), Post-thrombotic Syndrome and Venous Thromboembolism (VTE), sponsored by Azienda Sanitaria Locale ASL 6, Livorno. Not yet recruiting. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-02-25.
Sponsored by Azienda Sanitaria Locale ASL 6, Livorno · Phase 3, Interventional, and Prevention
Deep vein thrombosis (DVT) is a condition in which a blood clot forms in the deep veins of the leg and can lead to long-term problems such as leg pain, swelling, and reduced quality of life. Standard treatment with blood-thinning medication lowers the risk of complications, but some patients still develop long-term damage to the veins. Inflammation is thought to play an important role in these complications.
This study will evaluate whether adding colchicine, an anti-inflammatory medication already used for other conditions, to standard anticoagulant therapy can improve outcomes in patients with acute DVT. Participants will be randomly assigned to receive either colchicine or a placebo, in addition to usual blood-thinning treatment, and will be followed for one year.
The main goal of the study is to determine whether colchicine reduces the risk of developing long-term vein problems after DVT. The study will also assess the risk of new blood clots, vein recovery, quality of life, and the safety of colchicine treatment.
Deep vein thrombosis (DVT) of the lower limbs is a serious condition in which a blood clot forms in the deep veins of the leg. DVT can lead to long-term complications such as post-thrombotic syndrome (PTS), chronic leg swelling, pain, skin changes, and impaired quality of life. Standard treatment with anticoagulants helps prevent clot progression and reduces the risk of recurrent venous thromboembolism (VTE), but many patients still develop long-term vein damage.
Inflammation is believed to play a key role in clot development, vein-wall injury, and delayed resolution of DVT. Colchicine is an anti-inflammatory medication that has been widely used in other cardiovascular and inflammatory conditions and has a favorable safety profile when used in low doses. Preliminary studies suggest colchicine may help reduce inflammation associated with DVT and promote vein recovery.
The COLT-DVT study is a multicenter, randomized, double-blind, placebo-controlled clinical trial being conducted in Italy. The study will enroll approximately 940 adult patients with a first episode of acute proximal DVT of the lower limbs. Participants will be randomly assigned in a 1:1 ratio to receive either low-dose colchicine or a matching placebo, in addition to standard anticoagulant therapy. Colchicine treatment will be administered as 0.5 mg twice daily for the first month, followed by 0.5 mg once daily for the subsequent five months. Participants will be followed for a total of 12 months.
The main goal of the study is to determine whether the addition of colchicine reduces the incidence of post-thrombotic syndrome one year after DVT. Secondary objectives include assessing recurrent VTE, vein reopening and valve function via duplex ultrasound, health-related quality of life using validated questionnaires, and the safety and tolerability of colchicine treatment.
This study aims to provide new evidence on whether targeting inflammation in DVT can improve patient outcomes, reduce long-term complications, and potentially change standard care practices. Participants will be closely monitored for safety, and any side effects will be recorded and managed according to standard clinical practice.
785 studies on the registry are indexed under Venous Thrombosis; 110 are open to participants now.
This study's planned enrollment of 940 is above the median of 152 across 477 interventional studies indexed under Venous Thrombosis.
Browse Venous Thrombosis studies →Azienda Sanitaria Locale ASL 6, Livorno is the lead sponsor of 3 studies on the registry; 1 is open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Planned initiation of standard anticoagulation therapy, including:
Exclusion Criteria:
Participants meeting any of the following criteria will be excluded:
History of active or chronic gastrointestinal disease that may interfere with colchicine tolerance, including:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Creatinine clearance (CrCl)
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Life expectancy
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CYP3A (CYP3A4) inhibitors and inducers
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants in this arm will receive low-dose colchicine in addition to standard anticoagulant therapy for deep vein thrombosis. Colchicine will be administered as 0.5 mg twice daily for the first month, followed by 0.5 mg once daily for the subsequent five months. Participants will be monitored for safety, efficacy, and outcomes including post-thrombotic syndrome, recurrent venous thromboembolism, vein recanalization, and quality of life over a 12-month follow-up period.
Drug: Colchicine 0.5 MG Oral Tablet
Participants in this arm will receive a matching placebo in addition to standard anticoagulant therapy for deep vein thrombosis. Placebo will be administered following the same schedule as colchicine (0.5 mg twice daily for one month, then 0.5 mg once daily for five months). Participants will be monitored for the same outcomes and safety measures over a 12-month follow-up period.
Drug: Placebo
Low-dose colchicine added to standard anticoagulant therapy for acute proximal deep vein thrombosis. Colchicine is administered 0.5 mg twice daily for the first month, then 0.5 mg once daily for the next five months. Participants are monitored for post-thrombotic syndrome, recurrent venous thromboembolism, vein recanalization, quality of life, and safety over 12 months.
Matching placebo administered alongside standard anticoagulant therapy on the same schedule as colchicine. Participants are monitored for the same outcomes and safety measures.
Post-thrombotic syndrome (PTS)
To determine whether addition of low-dose colchicine to standard anticoagulation reduces the incidence of PTS at 12 months in patients with acute proximal lower-limb DVT. PTS is defined as: chronic clinical condition that occurs after DVT, presenting with symptoms such as leg pain, heaviness, cramps, pruritus, and paresthesia, and signs such as edema, skin hyperpigmentation, venous ectasia, lipodermatosclerosis, or venous ulcer, in the previously thrombosed limb, between 3 to 12 months after the acute event, and not explained by other causes \[31\]. A Villalta score \> 5 is considered diagnostic for PTS.
Time frame: From the start of treatment to the 12-month follow-up visit
Recurrent venous thromboembolism.
To evaluate the effect of low-dose colchicine added to standard anticoagulation on the incidence of recurrent venous thromboembolism (VTE), defined as objectively confirmed recurrent DVT and/or pulmonary embolism (PE), within 12 months of the index event.
Time frame: From the start of treatment to the 12-month follow-up visit
Longitudinal evaluation of PTS severity
Subgroup analysis evaluating differences in efficacy of low-dose colchicine added to standard anticoagulation in mild (5-9) to moderate (10-14) to severe PTS (\> 15).
Time frame: From the start of treatment to the 12-month follow-up visit
Venous healing and function on imaging
To assess the effect of colchicine on venous recanalization and valvular competence at 3 months using duplex ultrasound, including: 1. vein compressibility, 2. residual vein obstruction, 3. presence of venous reflux.
Time frame: From the start of treatment to the 12-month follow-up visit
Change From Baseline in Health-Related Quality of Life (HRQOL) as Measured by the VEINES-QOL/Sym Questionnaire
Change from baseline in health-related quality of life as measured by the Venous Insufficiency Epidemiological and Economic Study - Quality of Life/Symptoms (VEINES-QOL/Sym) questionnaire. The VEINES-QOL score ranges from 0 to 100, with higher scores indicating better quality of life. The VEINES-Sym score ranges from 0 to 100, with higher scores indicating fewer symptoms.
Time frame: From the start of treatment to the 12-month follow-up visit
Adverse event and treatment discontinuation
To determine the 12-months safety profile of colchicine in this population (major and clinically relevant non-major bleeding, defined by ISTH definitions, gastrointestinal adverse events, neutropenia).
Time frame: From the start of treatment to the 12-month follow-up visit
Adherence and persistence to colchicine therapy
To evaluate adherence and persistence to colchicine treatment and to explore their association with clinical outcomes, including PTS severity and recurrent VTE.
Time frame: From the start of treatment to the 12-month follow-up visit
No study locations are listed for this record.
Plan to share: Yes — De-identified individual participant data (IPD) underlying the results reported in this study, including the analyzable dataset and data dictionary, will be made available.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report, Analytic code
Access criteria: Data will be available upon reasonable request to the corresponding author, following approval of a research proposal and in compliance with institutional and ethical regulations. Data will be shared in a de-identified format to protect participant confidentiality.
No publications or documents are linked to this record.
Start is estimated for Jun 2026; primary completion for Jun 2027, 12 months later.
Of 34 phase 3 interventional studies under Venous Thrombosis, half reached primary completion within 44 months of starting (the median), counting those still running; a quarter within 28 and three quarters within 58. This study's planned 12 months is below that.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Feb 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Colchicine
Azienda Sanitaria Locale ASL 6, Livorno