Digital Ulcers in Systemic SclerosisPhase 2TOP-N53-02NCT06954597
Safety and Tolerability of TOP-N53 Applied on Digital Ulcers in Patients With Systemic Sclerosis
A Phase 2 study testing TOP-N53 and Sildenafil in people with Digital Ulcers in Systemic Sclerosis, run by Topadur Pharma AG at 6 sites in 2 countries.
Trial summary
The main goal of this clinical trial is to learn about how safe the new drug TOP-N53 solution is when it is applied to open wounds on the fingertip (digital ulcers) in people with an uncommon illness that results in hard, thickened areas of skin and additional problems with internal organs and blood vessels (systemic… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Digital Ulcers in Systemic Sclerosis
- What is being tested?
- TOP-N53 and Sildenafil
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 15 participants
- Where
- 6 sitesin 2 countries
- Study dates
- 4 Feb 2025to 31 Oct 2026
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Participants who are able to understand and follow instructions during the clinical trial.
- Signed written informed consent in accordance with ICH-GCP and local legislation prior to admission to the clinical trial.
- Male or female participants aged ≥18 years of age at screening (V0) with SSc, limited or diffuse cutaneous, according to 2013 American College of Rheumatology (ACR)/EULAR criteria (*sex refers to biological characteristics).
- At least one active DU, considered as the cardinal DU, due to SSc, ≥2 mm in diameter at screening (V0) and baseline (V1/V1b) with at least an involvement of the dermis, located at the interphalangeal fingertip or on the volar surface distal to the proximal joint.
- Participants meeting one of the following 2 criteria:
- On stable PO sildenafil treatment at 20 mg TID [3 times per day] for at least 2 weeks prior screening (V0).
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- Not on any PO PDE5 inhibitor (sildenafil, tadalafil, vardenafil, mirodenafil) or unselective PDE inhibitors (theophylline, dipyridamole) at any dose (including for recreational purposes) for at least 4 weeks prior screening (V0).
- The physical examination must be without disease findings except SSc unless the investigator considers an abnormality to be irrelevant to the outcome of the clinical trial (screening [V0] and baseline [V1/V1b]).
- Concomitant medication as endothelin receptor antagonists, calcium channel blockers, and antiplatelets must have been used at stable doses at least 2 weeks prior to screening (V0), if applicable.
- Female volunteers of childbearing potential1 must either be permanently sterile or agree to use a highly effective birth control method (failure rate ˂1% per year when used consistently and correctly) throughout the clinical trial and for at least 7 weeks after last administration of IP.
- A male participant with a female partner of childbearing potential1 must agree to use adequate contraceptive methods (adequate contraceptive measures as required by local regulation or practice).
- Covered by health insurance system and/or in compliance with the recommendations of national law in force relating to biomedical research.
Who cannot join
- Any DU accompanied by one of the following complications: Clinical infection of active ulcer/peri-ulcer, osteitis, gangrene (screening [V0] and baseline [V1/V1b]).
- Participants with modified Rodnan Skin Score (mRSS) >35 (screening [V0]).
- Intractable pain from DUs (NRS ≥6) (screening [V0] and baseline [V1/V1b]).
- Active or previous history of calcinosis at the site of the designated cardinal DU.
- Unstable organ manifestations of SSc that require immediate medical attention and treatment e.g., scleroderma renal crisis, or where other organ manifestations of SSc (interstitial lung disease [ILD], pulmonary hypertension, gastrointestinal with malabsorption syndrome or bleeding, symptomatic primary myocardial involvement) are poorly controlled and/or are determinants of clinical symptomatology.
- Any documented active or suspected malignancy or history of malignancy within 5 years prior to the screening visit (V0), except appropriately treated basal cell carcinoma of the skin, actinic keratoses, "under surveillance" prostate cancer or in situ carcinoma of uterine cervix.
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- Participants with underlying chronic liver disease (Child Pugh A, B or C hepatic impairment).
- Participants with a significant disease or condition other than SSc which in the opinion of the investigator, may put the participant at risk because of participation, interfere with clinical trial procedures, or cause concern regarding the participant's ability to participate in the clinical trial or any medical condition which is expected to lead to a life expectancy <12 months.
- Systolic BP (SBP) <95 mmHg or diastolic BP (DBP) <50 mmHg , pulse rate <50 beats per minute at sitting position (if participant is very athletic as assessed by the investigator, exception to a pulse <50 bpm is permissible) at the screening visit (V0) or baseline visit (V1/V1b); one repeat measurement will be permitted.
- Clinically significant findings in the ECG at the screening visit (V0) or in historic ECG including 24 h Holter recordings, in particular prolongation of the QT interval corrected for HR (QTcB) ≥450 msec for men and ≥460 msec for women, ventricular arrhythmias or ectopic ventricular beats.
- Major surgery within 8 weeks prior to the screening visit (V0).
- Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) >1.5 x upper limit of normal (ULN) and total Bilirubin >1.5 x ULN.
- Estimated glomerular filtration rate (eGFR) (Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI] formula) formula ≤60 ml/min/1.73 m2 (corresponds to ≥ mildly to moderately reduced glomerular filtration rate [GFR]).
- Clinical laboratory values outside the reference range that in the investigator's opinion require further investigation and preclude enrollment into the clinical trial (clinically significant).
- Positive test for human immunodeficiency virus (HIV) antibodies, unless known from medical history.
- Positive hepatitis B-virus surface antigen (HBsAg) test, unless known from medical history.
- Positive anti-hepatitis C-virus antibodies (anti-HCV) test, unless known from medical history.
- Treatment with IV prostanoids: Either ongoing, or taken in the 4 weeks before enrollment or intended for the 4 weeks after last treatment with IP during the clinical trial.
- Treatments with PO prostanoids (selexipag), nitrovasodilators (e.g., glycerol trinitrate, isosorbide dinitrate, isosorbide mononitrate, molsidomine), soluble guanylate cyclase stimulators (riociguat) for 1 week prior screening (V0).
- Treatment with any other PDE5 inhibitor (tadalafil, vardenafil) except sildenafil if meeting inclusion criterion no. 5a or unselective PDE inhibitor (theophylline, dipyridamole) at any posology for the 4 weeks prior screening (V0) and during the clinical trial.
- Treatment with systemic glucocorticoids and immunosuppressants (unless used as stable background treatments for SSc at unchanged doses [as prescribed by participant's treating physicians] for at least 4 weeks prior to screening [V0]).
- Contraindications according to the IB of sildenafil and SmPC of Sildenafil-Teva only applicable for those participants meeting inclusion criterion no 5a:
- Hypersensitivity to the active substance or to any of the excipients of sildenafil.
- Co-administration with NO donors (such as amyl nitrite) or nitrates in any form due to the hypotensive effects of nitrates.
- However, in the current clinical trial with the topical, on wound administration of the NO donor and PDE5 inhibitor TOP-N53 as IP 2 in patients on sildenafil any risk of hypotensive effects are minimal because the plasma exposure of TOP-N53 is expected as < MABEL.
- The co-administration of PDE5 inhibitors, including sildenafil, with guanylate cyclase stimulators, such as riociguat, is contraindicated as it may potentially lead to symptomatic hypotension.
- Combination with the most potent of the CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, ritonavir).
- Participants who have loss of vision in one eye because of non-arteritic anterior ischaemic optic neuropathy (NAION), regardless of whether this episode was in connection or not with previous PDE5 inhibitor exposure.
- Recent history of stroke or myocardial infarction.
- Known or suspected hypersensitivities or known allergic reactions to components of the IPs or other dressings required for SoC during the clinical trial treatment.
- Known allergy to local amide anesthetics.
- Currently enrolled in another clinical investigation or clinical trial, or less than 30 days prior to screening visit (V0) (less than 2 months for any investigative clinical trials with PDE5 inhibitors, guanylate cyclase activators or stimulators, or any other intervention interfering with the broader cGMP pathway) since ending another clinical investigation or clinical trial(s), or receiving other investigational treatment(s).
- Pregnant women or breast-feeding women.
- In the opinion of the investigator the participant should not participate in the clinical trial if they are not expected to comply with the clinical trial protocol requirements or not expected to complete the clinical trial as scheduled.
- Close affiliation with the investigator (e.g., a close relative) or persons working at the clinical trial center(s) or participant is an employee of sponsor(s).
- Participant is institutionalized because of legal or regulatory order.
- Participant is vulnerable (under legal protection).
Trial locations and contacts
6 sites in 2 countries. Contact the study team or a site near you to ask about taking part.
6 sites in 2 countries
France4 sites, 4 recruiting
- Recruiting
Centre Hospitalier Universitaire de Bordeaux, Service de Rhumatologie
Bordeaux, 33000
Marie-Elise Truchetet, Professeur, +33.05.56.79.61.40, marie-elise.truchetet@chu-bordeaux.fr
Justine Landrin, +33.05.56.79.61.40, justine.landrin@chu-bordeaux.fr
- Recruiting
CHU Grenoble Alpes
La Tronche, 38 700
Zaza Putkaradze, +33(0) 4 76 76 78 42, zputkaradze@chu-grenoble.fr
Sophie Blaise, Professor
- Recruiting
CHRU Lille, Hôpital Claude Huriez, Rue Michel Polonosvski
Lille, 59000
Quentin Ducrocq, quentin.ducrocq@chu-lille.fr
David Launay, Prof
- Recruiting
Hôpital Cochin
Paris, 75014
Ouardia Berkouk, +33 (0)1 58 41 15 03, ouardia.berkouk@aphp.fr
Benjamin Chaigne, Dr
Switzerland2 sites, 2 recruiting
- Recruiting
Reha Rheinfelden, Salinenstrasse 98
Rheinfelden, Canton of Aargau, 4310
Corina Schuster, Dr, c.schuster@reha-rhf.ch
Ulrich Gerth, Dr
- Recruiting
Universitätsspital Zürich, Klinik für Rheumatologie, Rämistrasse 100
Zurich, Canton of Zurich, 8091
Eva-Maria Deschauer, Dr, +41 44 255 30 58, eva-maria.deschauer@usz.ch
Meier Chantal, Dr., +41 44 255 30 58, chantal.meier@usz.ch
About this study
Official title: Local and Systemic Safety and Tolerability of Ascending Doses of TOP-N53, a Nitric Oxide (NO)-Releasing Phosphodiesterase-5 (PDE5) Inhibitor, Administered Topically, on Wounds in Patients With Digital Ulcers (DU) in Systemic Sclerosis (SSc) in an Open-label, Vehicle-controlled, Phase 2a, Multi-center Clinical Trial
The main goal of this clinical trial is to learn about how safe the new drug TOP-N53 solution is when it is applied to open wounds on the fingertip (digital ulcers) in people with an uncommon illness that results in hard, thickened areas of skin and additional problems with internal organs and blood vessels (systemic sclerosis). Another goal is to learn if different strengths of TOP-N53 can treat certain aspects of the illness. Men and women between 18 and 69 years of age with this illness may participate in the clinical trial. A parallel treatment with Sildenafil 20 mg is allowed for clinical trial participants.
The main questions the clinical trial aims to answer are:
Read more
- Does TOP-N53 cause medical problems at the fingertip wound after it is directly applied to the wound?
- Does TOP-N53 affect certain aspects of the illness like blood flow in the fingertip wounds, itch, pain, redness, bruises and bleeding at or beyond the fingertip wounds?
Researchers will compare TOP-N53 solution in different strengths to a placebo (a look-alike substance that contains no drug) to see if TOP-N53 works to affect the aspects of the illness listed above.
Participants will receive one or two treatments with the placebo or different strengths of TOP-N53. The higher strength of the drug will only be given to participants after the lower strength was found to be safe.
Participants will visit the clinic up to 8 times within a maximum of 31 days. 2 visits may be done by telephone. The doctors will ask questions to ensure that it is safe for the participants to be in the clinical trial, apply the drug and follow-up on any medical problem after the treatment. They will also test if the drug works to treat the illness by several test methods before and after the treatment. Participants will help to find out whether the drug works to treat the illness and is safe by answering questions in a diary at different timepoints before and after treatment.
- Conditions
- Digital Ulcers in Systemic Sclerosis
- Being tested
- TOP-N53, Sildenafil, TOP-N53 vehicle
- Keywords
- digital ulcer, systemic sclerosis, safety, PDE5 inhibitor
- Medical subject headings
- digital ulcers, Scleroderma, Systemic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
TOP-N53Drug
TOP-N53 solution (IMP) containing 80 µg/ml TOP-N53 is applied topically directly to the digital ulcer of patients with systemic sclerosis. The dose if defined by volume and exposure time of the IMP.
SildenafilDrug
Parallel treatment with Sildenafil 20 mg 3-times per day is permitted if patient has been on a stable dose for 2 weeks prior to screening.
TOP-N53 vehicleDrug
TOP-N53 vehicle solution will be topically applied to digital ulcers of systemic sclerosis patients.
| Study group | Role | What they receive |
|---|---|---|
| Treatment step 1 | Placebo comparator | Treatment with vehicle (= 0 µg TOP-N53), 3h exposure Receives: Drug: Sildenafil; Drug: TOP-N53 vehicle |
| Treatment Step 2 | Experimental | Treatment with 2 µg TOP-N53, 3h exposure Receives: Drug: TOP-N53; Drug: Sildenafil |
| Treatment step 3 | Experimental | Treatment with 4 µg TOP-N53, 3h exposure Receives: Drug: TOP-N53; Drug: Sildenafil |
| Treatment step 4 | Experimental | Treatment with 8 µg TOP-N53, 3h exposure Receives: Drug: TOP-N53; Drug: Sildenafil |
| Treatment step 5 | Experimental | Treatment with 8 µg TOP-N53, 24h exposure Receives: Drug: TOP-N53; Drug: Sildenafil |
What is being measured
The primary outcome is the main question the study is designed to answer.
Local treatment emergent adverse events (TEAEs)
Frequency of local TEAEs from treatment initiation until follow-up (FU) visit
Measured: From first treatment until Follow-up visit; up to 37 days
Investigator-solicited digital ulcer (DU)-related patient reported outcome (DU-PRO) - Pain
Frequency and mean score of pain (actual) at the cardinal DU as assessed by using a numeric rating scale (NRS, graduating intensity from 0 ['no pain'] to 10 ['worst imaginable pain']).
Measured: Per dose/time escalation step at screening, at treatment days prior and several times after treatment as well as on follow-up visits during a maximum time period of 37 days.
Secondary outcomes (8)
Clinical digital ulcer (DU) assessment (CDUA) endpoint - erythema at the peri ulcer area of the cardinal DU
Frequency and mean score of erythema at the peri ulcer area of the cardinal DU (by scoring using a 7-point Robinson scale; score 0: no reaction, score 6: worst reaction (bullous reaction or grade 3-5 reaction spreading beyounf the DU)
Measured: Per dose/time escalation step at screening, at treatment days prior and several times after treatment as well as on follow-up visits during a maximum time period of 37 days.
Clinical digital ulcer (DU) assessment (CDUA) endpoint - bruising at the peri-ulcer area of the cardinal DU or beyond
Frequency of bruising at the peri-ulcer area of the cardinal DU or beyond (as assessed by closed question: YES/NO)
Measured: Per dose/time escalation step at screening, at treatment days prior and several times after treatment as well as on follow-up visits during a maximum time period of 37 days.
Clinical digital ulcer (DU) assessment (CDUA) endpoint - hemorrhage in the cardinal DU
Frequency of hemorrhage in the cardinal DU (as assessed by closed question: YES/NO)
Measured: Per dose/time escalation step at screening, at treatment days prior and several times after treatment as well as on follow-up visits during a maximum time period of 37 days.
Clinical digital ulcer (DU) assessment (CDUA) endpoint - perilesional newly emerging, wound related edema at the cardinal DU
Frequency of perilesional newly emerging, wound related edema at the cardinal DU (as assessed by closed question: YES/NO)
Measured: Per dose/time escalation step at screening, at treatment days prior and several times after treatment as well as on follow-up visits during a maximum time period of 37 days.
Clinical digital ulcer (DU) assessment (CDUA) endpoint - clinical infection at the cardinal DU
Frequency of clinical infection at the cardinal DU (as assessed by closed question: YES/NO)
Measured: Per dose/time escalation step at screening, at treatment days prior and several times after treatment as well as on follow-up visits during a maximum time period of 37 days.
Investigator-solicited digital ulcer (DU)-related patient reported outcome (DU-PRO) - Itching
Mean score of itching (actual) at the cardinal DU as assessed by using a numeric rating scale (NRS; graduating intensity from 0 ['no itch'] to 10 ['worst imaginable itch']).
Measured: Per dose/time escalation step at screening, at treatment days prior and several times after treatment as well as on follow-up visits during a maximum time period of 37 days.
Further investigator-solicited digital ulcer (DU) patient reported outcome (DU-PRO)
Number of Raynaud's phenomenon (RP) attacks since IP initiation (0-5 minutes time point) and number of RP attacks since IP removal (60 minutes time point). RP attacks are defined as episodes of reduced blood flow to the end of blood vessels usually in fingers and toes.
Measured: Per dose/time escalation step at 0-5 minutes after inititation of treatment and 60 minutes after removal of the IP within a time frame of up to 25 hours after IP application durng the trial period of up to 37 days.
Systemic TEAEs
Frequency of clinically significant abnormal values for:
- Vital signs: Mean systemic arterial blood pressure and mean pulse rate, aural body temperature (only at screening, the enrollment visit for sildenafil participants, prior IP exposure when participant arrives, and at the Follow-up visit),
- 12 lead electrocardiogram (ECG): mean and mean changes in ECG values,
- Safety laboratory (clinical chemistry, hematology, urinalysis, serology): mean and mean changes in laboratory values.
Measured: From treatment initiation until Follow-up visit; up to 37 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 May 2025
- Study start4 Feb 2025
- Primary completion31 Oct 2026 (estimated)
- Study completion31 Oct 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Digital Ulcers in Systemic SclerosisStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Model description
- The treatment will be performed sequentially with ascending doses and treatment durations of the IMP starting with placebo treatment. The next higher dose will only be applied after safety evaluation of data of at least 2 participants per treatment group.
- Masking
- None (open label)
- Enrolment
- 15 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Topadur Pharma AG
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Bioskin GmbH
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06954597
- Sponsor's protocol ID
- TOP-N53-02
- Other IDs
- 2024-511861-12-00
- Acronym
- TOP-N53-02
- Status last verified
- Sep 2026
- First submitted
- 14 Apr 2025
- Last updated
- 1 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Apart from commercially confidential information related to the IMP, data collected in the course of this clinical trial is sparse. Therefore, there is no intention to share data as no benefit for the patient community is expected by the Sponsor. This will be reconsidered if larger cohort studies are initiated in the course of the development program.
Study at a glance
From the registry record, last updated by the sponsor on 1 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Local and Systemic Safety and Tolerability of Ascending Doses of TOP-N53, a Nitric Oxide (NO)-Releasing Phosphodiesterase-5 (PDE5) Inhibitor, Administered Topically, on Wounds in Patients With Digital Ulcers (DU) in Systemic Sclerosis (SSc) in an Open-label, Vehicle-controlled, Phase 2a, Multi-center Clinical Trial
- ClinicalTrials.gov ID
- NCT06954597
- Acronym / sponsor ID
- TOP-N53-02 / TOP-N53-02
- Conditions
- Digital Ulcers in Systemic Sclerosis
- Keywords
- digital ulcer, systemic sclerosis, safety, PDE5 inhibitor
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 15 participants (estimated)
- Lead sponsor
- Topadur Pharma AGIndustry (pharma, biotech, devices)
- Collaborators
- Bioskin GmbH
- Study start
- 4 Feb 2025 (actual)
- Primary completion
- 31 Oct 2026 (estimated)
- Study completion
- 31 Oct 2026 (estimated)
- First posted
- 1 May 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The main goal of this clinical trial is to learn about how safe the new drug TOP-N53 solution is when it is applied to open wounds on the fingertip (digital ulcers) in people with an uncommon illness that results in hard, thickened areas of skin and additional problems with internal organs and blood vessels (systemic sclerosis). Another goal is to learn if different strengths of TOP-N53 can treat certain aspects of the illness. Men and women between 18 and 69 years of age with this illness may participate in the clinical trial. A parallel treatment with Sildenafil 20 mg is allowed for clinical trial participants.
The main questions the clinical trial aims to answer are:
- Does TOP-N53 cause medical problems at the fingertip wound after it is directly applied to the wound?
- Does TOP-N53 affect certain aspects of the illness like blood flow in the fingertip wounds, itch, pain, redness, bruises and bleeding at or beyond the fingertip wounds?
Researchers will compare TOP-N53 solution in different strengths to a placebo (a look-alike substance that contains no drug) to see if TOP-N53 works to affect the aspects of the illness listed above.
Participants will receive one or two treatments with the placebo or different strengths of TOP-N53. The higher strength of the drug will only be given to participants after the lower strength was found to be safe.
Participants will visit the clinic up to 8 times within a maximum of 31 days. 2 visits may be done by telephone. The doctors will ask questions to ensure that it is safe for the participants to be in the clinical trial, apply the drug and follow-up on any medical problem after the treatment. They will also test if the drug works to treat the illness by several test methods before and after the treatment. Participants will help to find out whether the drug works to treat the illness and is safe by answering questions in a diary at different timepoints before and after treatment.
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 5
- Model description
- The treatment will be performed sequentially with ascending doses and treatment durations of the IMP starting with placebo treatment. The next higher dose will only be applied after safety evaluation of data of at least 2 participants per treatment group.
| Arm | Type | Receives |
|---|---|---|
| Treatment step 1 | Placebo comparator | Drug: Sildenafil, Drug: TOP-N53 vehicleTreatment with vehicle (= 0 µg TOP-N53), 3h exposure |
| Treatment Step 2 | Experimental | Drug: TOP-N53, Drug: SildenafilTreatment with 2 µg TOP-N53, 3h exposure |
| Treatment step 3 | Experimental | Drug: TOP-N53, Drug: SildenafilTreatment with 4 µg TOP-N53, 3h exposure |
| Treatment step 4 | Experimental | Drug: TOP-N53, Drug: SildenafilTreatment with 8 µg TOP-N53, 3h exposure |
| Treatment step 5 | Experimental | Drug: TOP-N53, Drug: SildenafilTreatment with 8 µg TOP-N53, 24h exposure |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (12 listed)
- Participants who are able to understand and follow instructions during the clinical trial.
- Signed written informed consent in accordance with ICH-GCP and local legislation prior to admission to the clinical trial.
- Male or female participants aged ≥18 years of age at screening (V0) with SSc, limited or diffuse cutaneous, according to 2013 American College of Rheumatology (ACR)/EULAR criteria (*sex refers to biological characteristics).
- At least one active DU, considered as the cardinal DU, due to SSc, ≥2 mm in diameter at screening (V0) and baseline (V1/V1b) with at least an involvement of the dermis, located at the interphalangeal fingertip or on the volar surface distal to the proximal joint.
- Participants meeting one of the following 2 criteria:
Key exclusion criteria (37 listed)
- Any DU accompanied by one of the following complications: Clinical infection of active ulcer/peri-ulcer, osteitis, gangrene (screening [V0] and baseline [V1/V1b]).
- Participants with modified Rodnan Skin Score (mRSS) >35 (screening [V0]).
- Intractable pain from DUs (NRS ≥6) (screening [V0] and baseline [V1/V1b]).
- Active or previous history of calcinosis at the site of the designated cardinal DU.
- Unstable organ manifestations of SSc that require immediate medical attention and treatment e.g., scleroderma renal crisis, or where other organ manifestations of SSc (interstitial lung disease [ILD], pulmonary hypertension, gastrointestinal with malabsorption syndrome or bleeding, symptomatic primary myocardial involvement) are poorly controlled and/or are determinants of clinical symptomatology.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| TOP-N53TOP-N53 solution (IMP) containing 80 µg/ml TOP-N53 is applied topically directly to the digital ulcer of patients with systemic sclerosis. The dose if defined by volume and exposure time of the IMP. | Drug | Treatment Step 2, Treatment step 3, Treatment step 4, Treatment step 5 |
| SildenafilParallel treatment with Sildenafil 20 mg 3-times per day is permitted if patient has been on a stable dose for 2 weeks prior to screening. | Drug | Treatment Step 2, Treatment step 1, Treatment step 3, Treatment step 4, Treatment step 5 |
| TOP-N53 vehicleTOP-N53 vehicle solution will be topically applied to digital ulcers of systemic sclerosis patients. | Drug | Treatment step 1 |
Primary outcome
Local treatment emergent adverse events (TEAEs)
Time frame: From first treatment until Follow-up visit; up to 37 days
Frequency of local TEAEs from treatment initiation until follow-up (FU) visit
Investigator-solicited digital ulcer (DU)-related patient reported outcome (DU-PRO) - Pain
Time frame: Per dose/time escalation step at screening, at treatment days prior and several times after treatment as well as on follow-up visits during a maximum time period of 37 days.
Frequency and mean score of pain (actual) at the cardinal DU as assessed by using a numeric rating scale (NRS, graduating intensity from 0 ['no pain'] to 10 ['worst imaginable pain']).
8 secondary outcomes
Clinical digital ulcer (DU) assessment (CDUA) endpoint - erythema at the peri ulcer area of the cardinal DU
Time frame: Per dose/time escalation step at screening, at treatment days prior and several times after treatment as well as on follow-up visits during a maximum time period of 37 days.
Clinical digital ulcer (DU) assessment (CDUA) endpoint - bruising at the peri-ulcer area of the cardinal DU or beyond
Time frame: Per dose/time escalation step at screening, at treatment days prior and several times after treatment as well as on follow-up visits during a maximum time period of 37 days.
Clinical digital ulcer (DU) assessment (CDUA) endpoint - hemorrhage in the cardinal DU
Time frame: Per dose/time escalation step at screening, at treatment days prior and several times after treatment as well as on follow-up visits during a maximum time period of 37 days.
Clinical digital ulcer (DU) assessment (CDUA) endpoint - perilesional newly emerging, wound related edema at the cardinal DU
Time frame: Per dose/time escalation step at screening, at treatment days prior and several times after treatment as well as on follow-up visits during a maximum time period of 37 days.
Clinical digital ulcer (DU) assessment (CDUA) endpoint - clinical infection at the cardinal DU
Time frame: Per dose/time escalation step at screening, at treatment days prior and several times after treatment as well as on follow-up visits during a maximum time period of 37 days.
Investigator-solicited digital ulcer (DU)-related patient reported outcome (DU-PRO) - Itching
Time frame: Per dose/time escalation step at screening, at treatment days prior and several times after treatment as well as on follow-up visits during a maximum time period of 37 days.
Further investigator-solicited digital ulcer (DU) patient reported outcome (DU-PRO)
Time frame: Per dose/time escalation step at 0-5 minutes after inititation of treatment and 60 minutes after removal of the IP within a time frame of up to 25 hours after IP application durng the trial period of up to 37 days.
Systemic TEAEs
Time frame: From treatment initiation until Follow-up visit; up to 37 days
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 Oct 2026.
- Individual participant dataSharing planned: No. Apart from commercially confidential information related to the IMP, data collected in the course of this clinical trial is sparse. Therefore, there is no intention to share data as no benefit for the patient community is expected by the Sponsor. This will be reconsidered if larger cohort studies are initiated in the course of the development program.
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Scleroderma, Systemic, Digital Ulcer
Not yet recruitingPhase 3
Efficacy of A Non-Invasive Botulinum Toxin Microneedle Pad for the Treatment of Secondary Raynaud's Phenomenon
Systemic Sclerosis (SSc), Raynaud Disease Secondary to Scleroderma
Not yet recruiting
Extracellular Vesicle Dynamics Predicting Vascular Complications and Treatment Response in Systemic Sclerosis
Systemic Sclerosis, Pulmonary Arterial Hypertension
Enrolling by invitationObservational study
Hand Disability In Systemic Sclerosis - Digital Ulcers
Systemic Sclerosis (SSc), Digital Ulcer
RecruitingPhase 2
Subcutaneous Injections of ASC to Heal Digital Ulcers in Patients With Scleroderma.
Systemic Sclerosis
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
6 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing TOP-N53 and Sildenafil in people with Digital Ulcers in Systemic Sclerosis, run by Topadur Pharma AG at 6 sites in 2 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 12 inclusion and 37 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 1 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 6 sites in France, Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Claudia Berger, Ph.D. (+41792025755, claudia.berger@Topadur.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Local treatment emergent adverse events (TEAEs) (time frame: From first treatment until Follow-up visit; up to 37 days). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 1 Oct 2026.