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Study of sildenafil to improve walking distance in patients with peripheral arterial disease and intermittent claudication

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 study focuses on Peripheral Arterial Disease, a condition where blood flow to the legs is reduced, causing pain while walking (known as intermittent claudication). The study will test whether sildenafil citrate can help patients walk longer distances compared to placebo. This medication will be taken orally as tablets for a period of 24 weeks.

The main goal is to determine if sildenafil can improve walking ability in people who experience leg pain that limits their walking distance. Participants will use a treadmill to measure how far they can walk before being stopped by leg pain. The study will track changes in walking distance over time and monitor other aspects of vascular health.

During the study, participants will take either sildenafil or placebo tablets daily. The maximum daily dose of sildenafil will be 140 mg. Throughout the study period, various measurements will be taken to assess walking ability, blood vessel function, and overall health status. The total duration of follow-up will be 48 weeks to evaluate the long-term effects of the treatment.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    You will undergo a treadmill test to measure your walking capacity. You will walk until you cannot continue due to leg pain, or for a maximum of 15 minutes.

    Your doctor will perform several baseline measurements including endothelial function (blood vessel health), pulmonary function (breathing capacity), and blood pressure tests.

    You will complete two questionnaires about your health and quality of life: the SF36 and Peripheral Artery Questionnaire.

  2. Step 2

    Treatment period - First 12 weeks

    You will receive either sildenafil or a placebo (inactive substance) to take by mouth. Neither you nor your doctor will know which one you are receiving.

    After 12 weeks, you will repeat the treadmill test, questionnaires, and other health measurements.

  3. Step 3

    Treatment period - Week 24

    At week 24, you will undergo another complete assessment including the treadmill test, questionnaires, and all health measurements.

    Your walking capacity will be compared to your initial test to measure any improvements.

  4. Step 4

    Final assessment - Week 48

    The final evaluation will take place at week 48.

    You will complete the final treadmill test, questionnaires, and health measurements.

    Your doctor will assess if you have experienced any significant health events during the study period.

  5. Step 5

    Monitoring throughout the study

    Your doctor will monitor your health and any symptoms you experience throughout the 48-week period.

    The study will track how well you follow the treatment plan and any side effects you may experience.

Who can join the trial?

7 criteria

  • Must be 18 years or older
  • Must have peripheral artery disease confirmed by at least one of these tests: - Ankle-brachial index (ABI) of 0.90 or less - Toe-brachial index (TBI) of 0.70 or less - Decrease in ABI by 18.5% after exercise - Specific exercise test showing reduced oxygen levels in tissues
  • Must have stable limiting claudication (pain in legs during walking that forces you to stop) despite receiving standard medical treatment for at least 4 weeks, including: - Blood-thinning medications - Cholesterol-lowering drugs - Blood pressure medications - Regular walking advice
  • Must be able to walk no more than 500 meters during a treadmill test
  • Must be registered with a social security agency
  • Must be able to understand the study requirements and provide written informed consent
  • Both men and women may participate

Who cannot join the trial?

15 criteria

  • Age below 18 or above 80 years old
  • History of severe heart problems or recent heart attack (within last 6 months)
  • Uncontrolled high blood pressure (blood pressure above 170/100 mmHg)
  • Current use of nitrate medications (medications for chest pain or heart conditions)
  • Severe kidney or liver disease
  • History of stroke in the past 6 months
  • Active bleeding disorders
  • Current treatment with medications that interact with sildenafil
  • Pregnancy or breastfeeding
  • Participation in other clinical trials within the last 30 days
  • Known allergic reactions to sildenafil or similar medications
  • Severe vision problems, including a condition called retinitis pigmentosa (a genetic disorder affecting the eyes)
  • Active stomach ulcers
  • Inability to walk independently
  • Mental conditions that could affect the ability to provide informed consent
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Investigated drugs

Sildenafil is a medication that helps improve blood flow throughout the body. In this trial, it is being studied for its potential to help people with peripheral arterial disease walk longer distances without pain. While this medication is commonly known for treating erectile dysfunction, researchers are investigating its ability to improve circulation in leg arteries, which could help patients who experience pain and difficulty walking due to poor blood flow in their legs.

What is already known about the treatment

Sildenafil - A prescription medication administered orally in tablet form, primarily known for treating peripheral arterial disease and its symptoms, particularly intermittent claudication (pain while walking due to poor circulation). This phosphodiesterase type 5 (PDE5) inhibitor works by relaxing blood vessels and improving blood flow to various parts of the body, helping patients achieve better walking capacity and reduced claudication symptoms. Originally developed for cardiovascular conditions, sildenafil has proven effective in multiple therapeutic areas and continues to be studied in clinical trials for various vascular disorders, with its mechanism of action involving the nitric oxide-cGMP pathway that regulates blood vessel dilation.

Investigated diseases

Peripheral Arterial Disease - A circulatory condition where narrowed arteries reduce blood flow to the limbs, most commonly affecting the legs. The condition develops gradually as arteries become hardened and narrowed due to the buildup of fatty deposits called plaque on artery walls. The reduced blood flow causes pain during walking (claudication), which typically subsides with rest. As the disease progresses, patients may experience leg pain even at rest, along with numbness and coldness in the lower legs and feet. The condition can also lead to slow-healing sores on the legs and feet.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-516429-30-00Protocol code35RC17_8844_VIRTUOSEEstimated enrolment220 patientsSponsorCentre Hospitalier Universitaire De Rennes

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).