This study is being done to find out if an investigational product called HP802-247 can help people with venous leg ulcers. Investigational means that HP802-247 has not been approved by the U.S. Food and Drug Administration (FDA).

At least 250 subjects will participate. The study is going to be conducted in approximately 50 sites in the United States and Canada.

This research is being done to compare the efficacy of HP802-247 plus compression therapy against Vehicle plus compression therapy in achieving complete wound closure over the 16-week treatment period. Vehicle looks the same as HP802-247 but contains no cells. Target wound status is evaluated at each study visit (closed, open, reopened). At wound closure or completion of treatment all subject will enter an observational safety followed up period which ends at one year after initial exposure to test article.

Inclusion Criteria:

• Provide informed consent.
• Age ≥ 18 years and of either sex.
• Willing to comply with protocol instructions, including allowing all study assessments.
• Have a venous leg ulcer (VLU) between the knee and ankle (at or above the malleolus), with a surface area >12 cm2 to ≤ 36 cm2
• Venous insufficiency confirmed by duplex Doppler ultrasound examination for valvular or venous incompetence.
• Arterial supply adequacy confirmed
• Target ulcer involves a full thickness skin loss, but WITHOUT exposure of tendon, muscle, or bone.
• Target ulcer duration ≥ 6 weeks but ≤ 104 weeks (24 months).
• Acceptable state of health and nutrition

Exclusion Criteria:

• History of anaphylaxis, serum sickness, or erythema multiforme reaction to aprotinin, bovine serum albumin or bovine serum proteins, penicillin, streptomycin, amphotericin B.
• Prior diagnosis of Systemic Lupus Erythematosus with elevated anti-DNA antibody titers, Buerger's disease (thromboangiitis obliterans), current diagnosis of vasculitis, or current diagnosis of claudication.
• Therapy with another investigational agent within thirty (30) days of Screening, or during the study.
• A target ulcer of non-venous etiologies (e.g., sickle cell anemia, necrobiosis lipoidica diabeticorum, pyoderma gangrenosum, vasculopathic or vasculitic).
• Documented history of osteomyelitis at the target wound location within 6 months preceding the Screening Visit.
• Refusal of or inability to tolerate compression therapy.
• Therapy of the target ulcer with autologous skin graft, Apligraf™, or Dermagraft™ within 30 days preceding the Screening Visit.
• History of cancer in the preceding 5 years (other than carcinoma in situ of the cervix or adequately treated non-melanoma skin cancers).
• Any prior exposure to HP802-247 or its vehicle.

Results summaries have been sent to each site for distribution to participants