Chronic wounds, such as diabetic ulcers, pressure ulcers, and venous stasis ulcers, cause significant morbidity in millions of patients each year in the United States. Individuals with long-standing diabetes develop both peripheral vascular disease and peripheral neuropathy. These patients may not feel pressure from shoes or objects which can damage their skin. Once a wound is formed, it may heal very slowly or not at all due to diabetic complications.

Platelet-derived growth factor-B (PDGF-B) has been approved for use in diabetic ulcers. However, delivery and maintenance of the drug at the wound site in sufficient quantities for a sufficient period of time is a major hurdle to widespread use.

Gene activated matrix (GAM) technology offers the opportunity to place a therapeutic gene contained within a structural matrix into a wound site. This study will evaluate the safety and potential clinical utility of topical applications of GAM501, a gene for PDGF-B contained within an E1-deleted adenoviral vector and formulated in a bovine type I collagen gel. This formulation allows for the migration of wound repair cells into the structural matrix, where they encounter the viral vector and subsequently produce the therapeutic protein within the local wound environment.

Participants in this study will receive up to four treatments with GAM501. Participants will be followed by multiple observations over a 6 to 7 month period.

Inclusion Criteria

• Adequately controlled diabetes mellitus (type I or II) as defined by HbA1c < 10.0%
• Cutaneous, lower extremity, plantar medial or lateral surface ulcer between 1 and 10 cm2 post-debridement
• Ulcer present for > 6 weeks prior to study entry
• Ulcer free of all necrotic and infected soft tissue
• Affected limb transcutaneous oxygen pressure (TcpO2) > 30 mmHg at screening or a palpable dorsal pedal or posterior tibial pulse
• Inability to perceive 10 grams pressure using a Semmes-Weinstein 5.07 monofilament in the peri-ulcer area