after providing informed consent, a baseline visit is scheduled.

during this visit, the study team records personal information, measures vital signs (such as blood pressure and heart rate), performs a physical examination, obtains a 12‑lead ecg (a test that records the heart’s electrical activity), and collects blood and urine samples for laboratory analysis.

the chronic wound is measured in size (area in cm²) and evaluated using a wound‑bed score and a pain scale.

a single fb-plus topical patch containing a low amount of human fibroblasts (cells taken from a donor) is applied to the wound.

the patch is placed on the wound and left in place according to the protocol (usually for a few days).

no repeat dosing is required; the study evaluates the effect of this one application.

follow‑up visits are conducted to observe any treatment‑emergent adverse events (new side effects that appear after the patch is applied).

at each visit, the team repeats the physical exam, checks vital signs, reviews the ecg, and repeats blood and urine tests to detect any changes.

the investigator records tolerability using a 5‑point scale, where 1 indicates the patch was very well tolerated and 5 indicates it was not tolerated at all.

if the low‑strength patch is found to be safe, a second group receives a single fb-plus topical patch with a higher amount of human fibroblasts.

the application procedure is identical to the first step: the patch is placed on the wound and left in place as directed.

the same series of follow‑up visits and examinations described in step 3 are performed to assess safety, tolerability, and any adverse events associated with the higher dose.

based on the safety and tolerability information gathered from the two dose groups, the investigators choose the dose that showed the best balance of safety and potential benefit.

this selected dose will be used in the next part of the study.

participants receive one fb-plus topical patch containing the selected dose of human fibroblasts.

the patch is applied once to the wound, following the same procedure as in the escalation phase.

regular visits are scheduled to evaluate wound healing. measurements include ulcer size change, wound‑bed score, pain level (using a visual analogue scale), and patient‑reported quality of life.

the investigator also records any adverse events and repeats the safety examinations (vital signs, ecg, blood and urine tests).

the overall satisfaction with the product’s efficacy is rated on a 5‑point scale.

at the end of the study period, a final assessment is performed to summarize safety, tolerability, and wound‑healing results.

the data are compiled to determine whether the treatment met the study objectives.