This is a follow-up study to evaluate the safety for the subjects with ALLO-ASC-DFU treatment in phase 3 clinical trial (ALLO-ASC-DFU-301) for 24 months

This is an open-label follow up study to evaluate the safety for the subjects with ALLO-ASC-DFU treatment in phase 3 clinical trial (ALLO-ASC-DFU-301) for 24 months. ALLO-ASC-DFU is a hydrogel sheet containing allogenic adipose-derived mesenchymal stem cells. Adipose-derived stem cells have anti-inflammatory effect and release growth factors such as vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF), which can enhance wound healing and regeneration of new tissue, finally may provide a new option in treating a Diabetic Foot Ulcer.

Inclusion Criteria:

1. Subjects who are treated with ALLO-ASC-DFU sheet or Vehicle sheet in phase 3 clinical trial of ALLO-ASC-DFU-301.
2. Subjects who are able to give written informed consent prior to study start and to comply with the study requirements.

Exclusion Criteria:

1. Subjects who are considered not suitable for the study by the principal investigator.

Subjects who are treated with ALLO-ASC-DFU sheet or Vehicle sheet in phase 3 clinical trial of ALLO-ASC-DFU-301.