This is a prospective, multi-national, multi-centre, randomized, non-blinded (photo evaluation is blinded), controlled clinical investigation in patients suffering from diabetic wounds reaching to tendon, bone, or joint. Patients will be randomised to received intact fish skin (Kerecis™ Omega3 Wound) plus standard of care or standard of care alone, and wound healing compared over 16 weeks.

This study is a multi-center study in France, Germany, Italy, and Sweden on the healing effect of Kerecis™ Omega3 Wound in severe diabetic ulcers and open amputation wounds compared to standard of care treatment.

Cell and/or tissue based wound treatment products (CTPs) have been advancing in the treatment of non-healing ulcers in the last 20 years. In 2013, a new product was approved in Europe and by the FDA, intact fish skin, delivered as a sterilized, freeze-dried material, for the treatment of acute and chronic wounds. Fish skin has the benefit of not requiring treatment with antibiotics, or virus inactivating methods, thereby allowing the natural content of the skin to remain, and is a by-product of food industry. Therefore, the fish derived CTP is both ecologically sustainable as well as rich in naturally occurring soluble molecules and omega-3 fatty acids.

A study evaluating the prognosis of diabetic ulcers from large registry data found that the deeper, larger, and more long-standing ulcers would take longer to heal. If a wound was older than 2 months, larger than 2 cm2 and reached bone or tendon, the likelihood of healing in 20 weeks was 19%. The average cost to close a diabetic foot wound with advanced moist wound healing has been calculated at €2300 per cm2, so closing a 3 cm2 wound would cost €6900..

A wealth of clinical experience on diabetic wounds exists on the Kerecis fish skin material. This is, however, mainly in the form of case series and has been published through posters and case reports. The main indication for Kerecis is deep or non-healing diabetic ulcers, which are the biggest problem in diabetic wound care ultimately leading to amputation. Studies on CTPs have almost solely been done on shallow diabetic ulcers to get a homogeneous study population which then is randomized to treatment with the studied product or the control product. This means that in the case of a favourable outcome in the study, those products are not really tested on the ulcer for which they are ultimately intended, ulcers where the next step is amputation.

This randomized controlled study on deep diabetic wounds is designed to prove the efficacy of Kerecis™ Omega3 Wound for the indications it is intended for - severe diabetic foot ulcers - and to show the cost effectiveness of using Kerecis™ Omega3 Wound over standard of care. Wounds resulting from an amputation that are left open with an opening into bone, or from a dehisced amputation where the sutures have gone up, are included. Acute amputations where the metatarsal bones are exposed are included, provided that the patient has diabetes and the amputation is a result of an ulcer.

This study is probably the first study on severe diabetic ulcers where the CTP is used on the types of wounds that it is intended for, thereby giving a straight answer to the actual savings included in healing a serious diabetic wound earlier or changing the stage to a smaller shallower ulcer (changing grade of ulcer), thus, radically changing the prognosis.

Inclusion Criteria:

• Diabetic patient with chronic lower extremity wounds: Grade 2 or 3 according to University of Texas score: Grade 2: "Wounds that penetrate to tendon or capsule". Grade 3: "wounds that penetrate to bone or into the joint". In this context, probing gently to bone means that the wound reaches bone.
• OR patients with diabetes that are recently amputated below the ankle, where the wound has not been closed or has dehisced and bones/tendons are exposed.
• Patients that have moderately decreased or normal arterial circulation. In this study the cutoff point is Ankle Brachial Index (ABP) below 0.6. (Toe pressure and TPCO2 values will be obtained if possible. Toe pressure of 50mmHg and a TCPO2 value of 40mm on the dorsum of the foot is often considered as indicative of adequate perfusion.)
• Patients who will tolerate aggressive debridement. Light bleeding of the wound surface should be seen after debridement.
• Patient has had his/her ulcer for one month.
• Participant is willing and able to give informed consent for participation in the clinical trial.
• Male or Female, over 18 years.
• Geographical distance compatible with taking part in the study. Observe though that the patient can be treated at a "home clinic" every other week as long as the end point is not imminent and photos and acetate tracers with cm markers are fed into the photo portal.
• Negative pregnancy test for a woman of childbearing age.
• Patient is able (in the investigator's opinion) and willing to comply with all the clinical trial requirements.

Exclusion Criteria:

• Patient whose wound surface is not measurable.
• Patients suffering from unmanaged osteomyelitis. With adequate treatment the patient can be re-screened for the study.
• Patient with severe ischemia (Ankle Brachial Index (ABI) <0.6).
• Patient with necrotic wound who will not tolerate aggressive debridement.
• Patient with immune deficiency or autoimmune disease.
• Patients having done arterial reconstruction within one month. These patients can be re-screened later.
• Patient on systemic corticosteroids or other treatments causing delayed wound healing.
• Female participants who are pregnant, breast feeding or planning pregnancy during the course of the clinical trial.
• Any other significant disease or disorder which, in the opinion of the Investigator, may either put the participants at risk because of participation in the clinical trial, or may influence the result of the clinical trial, or the participant's ability to participate in the clinical trial.
• Patient with known allergy to fish.
• Patient deprived of liberty by judicial or administrative decision, person subject to a legal protection measure.

Evaluation of wound closure at defined time points will be done by an assessor blinded to the treatment group.