This prospective, randomized, single-blind, controlled clinical investigation evaluates the efficacy and safety of ZKARE®, a topical polymeric gel dressing, and its accessory applicator ZKAPI®, for the treatment of chronic, hard-to-heal ulcers. The study includes 134 ulcers of different etiologies-pressure ulcers, neuropathic diabetic foot ulcers, and venous leg ulcers-meeting predefined selection criteria. Participants are randomized to receive either ZKARE® in addition to standard wound care or standard care alone.

The primary efficacy endpoint is the change in wound condition assessed through the RESVECH 2.0 scale, recorded at baseline and throughout treatment and follow-up visits. The primary safety endpoint is the incidence of serious adverse events (SAEs). Secondary outcomes include percentage and rate of wound closure, total closure rate, estimated time to full closure, quality-of-life measures (DLQI), patient satisfaction, investigator global assessment, cost-effectiveness, and product usability. The study aims to generate evidence on the performance, safety, and clinical usefulness of ZKARE® for chronic wound management.

Chronic ulcers such as pressure ulcers, neuropathic diabetic foot ulcers and venous leg ulcers frequently fail to follow normal healing phases and require comprehensive management. Many existing dressings act through a single mechanism and are limited in effectiveness for complex or exudative wounds. ZKARE® is a sterile, biocompatible polymeric gel intended for topical use that provides a moist microenvironment, absorbs excess exudate and contributes to bacterial control. The product is applied using ZKAPI®, a sterile Luer-Lock applicator designed to improve precision and ease of administration.

This prospective, randomized, single-blind, controlled clinical investigation compares ZKARE® plus standard care with standard care alone in 134 chronic ulcers of different etiologies. Patients may contribute more than one ulcer if lesions are independent. After informed consent, ulcers are randomized, and treatment sessions follow routine clinical practice, with ZKARE® added only in the investigational arm. Blinding is maintained by preventing direct visualization of the wound and through iso-appearance of materials. Follow-up visits occur at approximately 2, 4, 8 and 12 weeks.

The primary efficacy endpoint is the change in RESVECH 2.0 score, recorded at baseline, each treatment session and all follow-up visits; a ≥2-point improvement at Week 4 is considered clinically relevant. The primary safety endpoint is the incidence of serious adverse events. Secondary outcomes include percentage and rate of wound closure, total closure rate, estimated time to full closure, DLQI, patient satisfaction, investigator global assessment, usability and cost-effectiveness, as well as non-serious adverse events.

Group comparisons use appropriate statistical tests for categorical and continuous variables, repeated-measures analyses and ANCOVA where applicable, under an intention-to-treat approach. The sample size of 134 ulcers gives 80% power to detect expected differences in RESVECH 2.0 change. The study aims to evaluate the clinical performance and safety of ZKARE® and ZKAPI® in the treatment of chronic hard-to-heal ulcers

Inclusion Criteria:

• Adult patients (≥18 years).
• Presence of at least one chronic hard-to-heal ulcer, including any of the following etiologies: Grade II, III or IV pressure ulcers; neuropathic diabetic foot ulcers (grade I, II or III), Wagner Grade I-III or Texas 0, I, II, III / Stage B; class C6/C6r venous leg ulcers measured with CEAP scale ; neuro-ischaemic ulcers with adequate distal perfusion (ABI/ITB ≥ 0.7-0.89; mild PAD); mixed-etiology venous ulcers and any chronic lower-limb lesion with palpable distal pulses.
• Ulcer size between 1 cm² and 100 cm².
• Ability and willingness to comply with all study visits and procedures according to the clinical protocol.
• Ability to understand and sign the informed consent, obtained before performing any protocol-specific procedures.

Exclusion Criteria:

• Ulcers of etiologies not listed in the inclusion criteria.
• Ischaemic, neoplastic or atypical ulcers.
• Severe comorbidities judged to compromise safety or study compliance, including: severe malnutrition, palliative/terminal status, severe anemia, decompensated heart failure, chronic kidney disease stage III/IV or in dialysis.
• Ulcers with moderate-severe or severe infection per PEDIS-IDSA infection grading scale.
• Known allergy or sensitivity to any component of the investigational product.
• Any condition that, in the investigator's opinion, may compromise patient safety or adherence to the protocol.
• Pregnancy or planned breastfeeding.