The purpose of this research is to evaluate the safest and most effective dose of a Food and Drug Administration (FDA) approved drug (XIAFLEX) in the treatment of lipoma (fatty tumors of varying sizes that occur commonly in the adult population). The fat in the lipoma is like normal fat except that it is enclosed in a balloon-like structure which is made of collagen (fibrous tissue). Treatment of the lipoma with an injection of XIAFLEX (a protein that breaks down collagen fibers) may dissolve the collagen/fibrous strands thereby decreasing the size of the lipoma or removing it.

Lipomas are common mesenchymal, benign, fatty tumors of varying sizes that occur in the general adult population. They usually present as painful or annoying lumps that are palpable and often visible in the subcutaneous tissue. Many subcutaneous lipomas are asymptomatic and are removed for non-medical reasons. However, they may cause the subject pain or discomfort or interfere with normal activity.

Spontaneous remission of lipomas has not been reported. A lipoma, once it presents itself, remains there for the lifetime of a person who carries it and may stay small or become larger. Alternative treatments of the lipoma are surgery or liposuction. If a large excision is performed there is the problem of having a very large scar and the accompanying issues of healing a large scar, or possible formation of a hematoma followed by consolidation of the hematoma and the remnants of a mass of scar tissue. This is often painful and more problematic than the original lipoma. liposuction also has the potential for hematoma formation followed by scar mass residual.

To avoid the complications listed above, a non-invasive method of treatment, such as enzyme mediated disassociation of adipose tissue, would be desirable. The primary aim of this study is to perform a step-wise approach in dosing to evaluate the safety and efficacy of clostridium histolyticum as a non-operative treatment for lipoma.

Inclusion Criteria:

• Clinical history lipoma at least one year and no treatment within last 90 days
• Lipoma diagnosed as benign
• Lipoma is a single mass with easily definable edges
• Lipoma has an area of 2.0 to 17 cm squared
• Women of childbearing potential must use an acceptable method of birth control

Exclusion Criteria:

• Lipomas on the head, neck, hand or foot, or female breast
• Women who are nursing or pregnant
• Subjects who have participated in any investigational drug trial within 45 days of enrollment in this study
• Subjects with known allergy to collagenase or any of the inactive ingredients in XIAFLEX
• Subjects with diabetes or any medical condition that would make the subject unsuitable for enrollment.
• Subjects having a history of trauma in the area of the lipoma
• Subjects with a history of connective tissue diseases or rheumatological diseases.
• Subjects with uncontrolled hypertension
• Subjects currently receiving or planning to receive anticoagulant medication except for less than 150 mg aspirin daily and over-the-counter nonsteroidal anti-inflammatory drugs) within 7 days before injection of study drug
• Subjects having the following laboratory abnormalities:
• ALT/AST greater than 3 times the upper limit of normal
• Creatinine greater than 2
• Hemoglobin/hematocrit and WBC outside the normal range

Adverse Events were collected from Day 0 through 6 months post administration of study medication