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Study on the Safety of TOP-N53 for Treating Digital Ulcers in Systemic Sclerosis Patients

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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 safety and tolerability of a new treatment called TOP-N53 for patients with digital ulcers caused by systemic sclerosis. Systemic sclerosis, also known as scleroderma, is a condition that affects the skin and connective tissues, leading to the development of painful sores or ulcers on the fingers, known as digital ulcers. The treatment being tested, TOP-N53, is a solution that releases a substance called nitric oxide, which is applied directly to the wound. This study aims to understand how safe and tolerable this treatment is when used on these ulcers.

Participants in the study will receive different doses of TOP-N53 applied to their digital ulcers. The study will also include a comparison with a placebo, which is a substance with no active medication, to see how the treatment performs. The trial will observe the effects of the treatment over a period of time, with doses being increased gradually to assess how well patients tolerate the treatment and to monitor any side effects that may occur. The study will also collect information on how the treatment affects pain and other symptoms related to the ulcers.

Throughout the study, participants will be closely monitored by healthcare professionals to ensure their safety and to gather data on the treatment's effects. The goal is to determine if TOP-N53 can be a safe and effective option for managing digital ulcers in patients with systemic sclerosis. This research could potentially lead to new ways to help those suffering from this challenging condition.

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 visit and consent

    Upon joining the clinical trial, participants will attend an initial visit. During this visit, participants will be asked to provide written informed consent, confirming their understanding and agreement to participate in the study.

    Participants will undergo a physical examination to ensure they meet the eligibility criteria. This includes having at least one active digital ulcer due to systemic sclerosis, which is a condition affecting the skin and connective tissues.

  2. Step 2

    Baseline assessment

    Participants will have a baseline assessment to record their current health status. This includes measuring vital signs such as blood pressure and pulse rate, and conducting laboratory tests.

    An electrocardiogram (ECG) will be performed to check heart function. Participants will also be asked to complete a diary to record symptoms related to their digital ulcers, such as pain and itching.

  3. Step 3

    Treatment phase

    Participants will receive the investigational product TOP-N53 applied directly to their digital ulcers. The treatment will be administered in escalating doses: 0 micrograms (vehicle), 2 micrograms, 4 micrograms, and 8 micrograms.

    Each dose will be applied for a 3-hour exposure time, with the highest dose (8 micrograms) also being tested for a 24-hour exposure time. The treatment aims to assess the safety and tolerability of TOP-N53.

  4. Step 4

    Ongoing assessments

    Throughout the treatment phase, participants will have regular assessments to monitor their response to the treatment. This includes checking for any adverse effects and evaluating the condition of the digital ulcers.

    Participants will continue to complete their symptom diaries, noting any changes in pain, itching, or other symptoms related to their digital ulcers.

  5. Step 5

    Follow-up visit

    After the treatment phase, participants will attend a follow-up visit. This visit will occur approximately 7 to 9 days after the last treatment application.

    During the follow-up visit, participants will undergo a final assessment, including a physical examination, laboratory tests, and an ECG. The aim is to ensure the participant's safety and to gather final data on the treatment's effects.

Who can join the trial?

11 criteria

  • Participants who are able to understand and follow instructions during the clinical trial.
  • Covered by a health insurance system or in compliance with national laws related to biomedical research.
  • Signed written informed consent in accordance with international guidelines and local laws before joining the clinical trial.
  • Male or female participants aged 18 to 69 years with systemic sclerosis (SSc), which is a condition affecting the skin and other organs.
  • At least one active digital ulcer (DU) due to SSc, which is a sore on the fingertip, at least 3 mm in diameter, involving the skin layer called the dermis.
  • Participants must meet one of the following criteria:
    • On stable oral sildenafil treatment (20 mg, three times a day) for at least 2 weeks before screening.
    • Not taking any oral PDE5 inhibitors (like sildenafil, tadalafil) or unselective PDE inhibitors (like theophylline) for at least 4 weeks before screening.
    • The physical examination must not show any disease findings except for SSc, unless the investigator considers it irrelevant to the trial's outcome.
    • If applicable, medications like endothelin receptor antagonists, calcium channel blockers, and antiplatelets must have been used at stable doses for at least 2 weeks before screening.
    • Female volunteers who can have children must either be permanently sterile or agree to use a highly effective birth control method throughout the trial and for at least 7 weeks after the last administration of the investigational product.
    • A male participant with a female partner who can have children must agree to use adequate contraceptive methods as required by local regulations or practices.

Who cannot join the trial?

10 criteria

  • Patients with **active infections** that are not being treated. An active infection means you have a disease caused by germs, like bacteria or viruses, that is currently making you sick.
  • Patients who have **allergies** to any of the ingredients in the study medication. An allergy is when your body reacts badly to something, causing symptoms like itching or swelling.
  • Patients who are currently participating in another clinical trial. This means you are already part of a different study testing another treatment or medication.
  • Patients who have had a **major surgery** within the last 4 weeks. Major surgery is a big operation that usually requires a hospital stay.
  • Patients with **severe heart disease**. This refers to serious problems with the heart that affect how well it works.
  • Patients who are pregnant or breastfeeding. This means you are expecting a baby or are feeding a baby with milk from your body.
  • Patients with **uncontrolled diabetes**. Uncontrolled diabetes means your blood sugar levels are not being managed well, even with medication.
  • Patients with **severe kidney or liver disease**. This means your kidneys or liver are not working properly, which can affect your overall health.
  • Patients who have had a **stroke** in the past 6 months. A stroke is a medical emergency where blood flow to the brain is interrupted.
  • Patients with **cancer** that is not in remission. Cancer in remission means the disease is not currently active or growing.
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Investigated drugs

TOP-N53 is a special type of medication that is being tested to see if it can help heal wounds on the fingers of people with a condition called systemic sclerosis. This medication is applied directly to the wound in the form of a gel. It works by releasing a substance called nitric oxide, which can help improve blood flow and promote healing. The goal of the trial is to see if this medication is safe and well-tolerated when used on these types of wounds.

What is already known about the treatment

TOP-N53 – TOP-N53 is a medication applied directly to the skin in the form of a hydrogel, specifically on wounds caused by digital ulcers in patients with systemic sclerosis. It is currently being studied in clinical trials to assess its safety and tolerability. The main therapeutic use of TOP-N53 is to help heal digital ulcers, which are painful sores on the fingers. At the molecular level, it works by releasing nitric oxide, which helps to widen blood vessels and improve blood flow, thereby promoting healing. It is classified as a nitric oxide-releasing phosphodiesterase-5 (PDE5) inhibitor.

Investigated diseases

Digital ulcers in systemic sclerosis – Digital ulcers are open sores that occur on the fingers or toes, often as a result of reduced blood flow. In systemic sclerosis, a condition characterized by hardening and tightening of the skin and connective tissues, these ulcers can develop due to the narrowing of blood vessels. The progression of digital ulcers involves the initial appearance of small, painful sores that can become larger and more painful over time. They may lead to complications such as infection or tissue damage if not properly managed. The ulcers can cause significant discomfort and may interfere with daily activities due to pain and sensitivity. The condition is often associated with other symptoms of systemic sclerosis, such as skin thickening and changes in skin color.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase I/IITrial ID2024-511861-12-00Protocol codeTOP-N53-02Estimated enrolment15 patientsSponsorTopadur Pharma AG

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