Allogeneic ABCB5-positive Dermal Mesenchymal Stromal Cells for Treatment of Therapy-resistant CVU (Phase III)

Inclusion Criteria:

1. Patients at least 18 years old;

2. Chronic venous leg ulcer at lower leg and/or ankle region that has not been presentlonger than 15 years, diagnosed by Doppler or Duplex sonography, ankle brachialindex, physical examination and dermatological review;

3. Wound size at V1 and V2 between 1 and 25 cm˄2 as measured by standardizedphotography;

4. If patients have 2 or more ulcers at the same extremity, the target ulcer has to beseparated from the other ulcers with a bridge of epithelialized skin at least 1 cmwide;

5. Body mass index between 15 and 50 kg/m²;

6. Patients able to understand the nature of the study and able to provide writteninformed consent prior to any clinical trial procedures;

7. Women of childbearing potential must have a negative urine pregnancy test at Visit 1;

8. During the course of the clinical trial women of childbearing potential and theirmale partners must be willing to use highly effective contraceptive methods asdefined in the EMA CTCG "Recommendations related to contraception and pregnancytesting in clinical trials" Version 1.2.

Exclusion Criteria:

1. Evidence of the ulcer extending to the underlying muscle, tendon, or bone;

2. Uncontrolled Diabetes mellitus i.e. Hemoglobin A1c (HbA1c) >9.0% (75 mmol/mol) (measured by blood test);

3. Peripheral Artery Disease including claudication with need of treatment orintervention;

4. Acute deep vein thrombosis diagnosed within 30 days before V1, or untreated deepvein thrombosis;

5. Wounds showing size reduction of more than 40% at Visit 2 compared to Visit 1;

6. Patients with known hypersensitivity and/or clinical contraindications to thecompression systems used in the clinical trial, or inability/unwillingness totolerate leg ulcer compression systems;

7. Acute wound infection of ulcer requiring treatment as judged clinically;

8. Current use of medications that are known to influence wound healing i.e. systemicimmunosuppressives, cytotoxic medicinal products, systemic steroids (aboveCushingthreshold level) at investigator´s discretion;

9. Patients who, in the opinion of the investigator, for any reason are unable orunwilling to complete the trial per protocol (e.g. alcohol or substance abuse, notmobile, short life expectancy) or there is an evidence of any other medicalcondition (such as psychiatric illness, physical examination, or laboratoryfindings) that may interfere with the planned treatment, affect the patient'scompliance, or place the patient at high risk of complications related to thetreatment;

10. Any malignancy within the past 5 years, excluding successfully treated carcinoma insitu, basal cell carcinoma or squamous cell carcinoma of the skin without evidenceof metastases;

11. Pregnant or lactating women;

12. Known hypersensitivities to the active substance or to any of the excipients in theIP or the placebo;

13. Surgical procedure affecting the CVU, such as bypass or mesh graft performed withintwo months prior to Visit 1;

14. Current or previous (within 30 days of enrollment) treatment with another IP, orparticipation in another clinical trial, including follow-up phase;

15. Previous participation in this clinical trial (except for screening failures due toan inclusion or exclusion criterion);

16. Employees of the sponsor, or employees or relatives of the investigator(s).