This study is a platform study designed to efficiently test multiple biomarkers to identify diabetic foot ulcers (DFUs) with a higher potential for healing versus not healing that ultimately could be applied at the point of care to drive personalized management decisions, and to better inform clinical trials of wound healing interventions

This study is a platform study designed to efficiently test multiple biomarkers to identify diabetic foot ulcers (DFUs) with a higher potential for healing versus not healing that ultimately could be applied at the point of care to drive personalized management decisions, and to better inform clinical trials of wound healing interventions The platform study is designed to be flexible so that it is suitable for a wide range of studies relevant to patients with open (active) DFUs.

This platform study will enroll patients with DFUs seen in an outpatient setting in diabetic foot and wound care clinics across a range of healthcare systems, including community settings and tertiary care hospitals, participating in the DFC.

The platform study will include common procedures that are applicable across the entire spectrum of DFUs (e.g., uniform biospecimen collections, clinical and usual care characteristics, social determinants of health, and patient reported outcomes). Blood, wound fluid (by a variety of methods), wound dressings, and debridement tissue (if debridement is performed during the participant's clinical wound care) will be collected from all participants to support a biorepository for concurrent and future research. Urine samples will be collected if participants agree to provide them, and collection will be encouraged. Biomarker-specific studies requiring additional data or biospecimens not required in the platform study will be included as appendices, as needed. Other biomarker-specific studies that use platform study biospecimens and study data will follow the DFC ancillary study process.

Eligible participants enrolled in the master protocol who signed the informed consent may be enrolled in multiple biomarkers sub studies associated with the master protocol without the need to sign an additional informed consent.

This platform study is non-interventional; no study prescribed agents or therapies are administered.

Eligible and consented participants are managed at each DFC site according to the usual clinical care, which is expected to be in line with the current standards of care recommendations1-3. The study will collect relevant details regarding the care provided at each clinic visit and participant outcomes.

Follow-up for participants will vary based upon the occurrence and timing of healing:

• All participants will be followed every other week for one month and monthly thereafter until the wound is healed or week 52 if the wound has not healed.
• Participants who experience wound healing prior to week 52 will have a confirmation visit 2 weeks later. These participants will also be assessed for recurrence of their DFU at weeks 52 and 78 via phone call or video visit.
• Participants who experience wound healing at week 52 will have a confirmation visit 2 weeks later. These participants will also be assessed for recurrence of their DFU at week 78 via phone call or video visit.
• Participants who do not experience wound healing by week 52 will have an additional phone call or video visit scheduled at week 78 to assess patient-reported wound healing, infection, or amputation with confirmation by electronic medical records (EMR), if available.

Study visits may occur in conjunction with the participant's scheduled clinical follow-up visits. After wound healing has been confirmed, the visit may be conducted by remote means.

The master protocol will enable evaluation of the time to healing over a 78-week period and of expectations on the natural history of wound healing in contemporary DFU participants. It also enables exploring rates of DFU recurrence in those who healed. These data will lead to more accurate DFU-specific standards of care guidelines that will have a direct impact and benefit in the clinical care, for a personalized approach.

General and biomarker-specific analyses will be performed. Participants who share common demographic or clinical characteristics may be pooled across substudies.

Inclusion Criteria:

1. Provision of signed and dated informed consent form.
2. Age 18 years or older.
3. Clinically diagnosed with diabetes or meeting the American Diabetes Association (ADA) criteria. [ADA Standards of Clinical Care Diabetes Care 2022, Suppl 1]
4. Open foot ulcer, defined as an open wound from malleolus down. This includes post-surgical wounds within this area left open to heal by secondary intention. In case of multiple ulcers, the largest ulcer will be considered the study index DFU.
5. Agreement to adhere to protocol visits and provide all required biospecimens and clinical data.

Exclusion Criteria:

1. Participation in an interventional clinical trial for DFU within 1 month of Visit 1.
2. Currently receiving radiation to target area or chemotherapy.
3. Gangrene in any portion of the foot with the index ulcer.
4. Planned revascularization or under evaluation for revascularization of the index limb for advanced ischemia within next 4 weeks of Week 0.
5. Severe limb ischemia (SVS WIfl Ischemia grade 3).
6. Any concomitant medical or psychiatric condition that, in the opinion of the investigator(s), would compromise the participant's ability to safely complete the study.

Adults with diabetes with at least one open diabetic foot ulcer.