Abbott Laboratories announced the expansion of its immunology clinical trials program to include studies evaluating the potential of Humira (adalimumab) in psoriasis and psoriatic arthritis. Psoriasis and psoriatic arthritis are autoimmune disorders in which a human protein, tumor necrosis factor-alpha (TNF-a), has been suggested to play a role in the disease development. Data from clinical studies suggest that treatments that inhibit TNF-a may be effective in these disease states. Humira, which is a human monoclonal antibody that resembles antibodies normally found in the body, works by specifically blocking TNF-a.

Humira is the first human monoclonal antibody approved by the U.S. Food and Drug Administration (FDA) for reducing the signs and symptoms and inhibiting the progression of structural damage in adults with moderately to severely active rheumatoid arthritis (RA) who have had insufficient response to one or more traditional disease modifying antirheumatic drugs (DMARDs) and can be used alone or in combination with methotrexate (MTX) or other DMARDs. Humira was created using phage display technology, resulting in an antibody with human-derived heavy and light chains variable regions and human IgG1:K constant regions. The European Agency for the Evaluation of Medicinal Products (EMEA) accepted Abbott's submission for Humira for the treatment of RA in April 2002, and approval is anticipated in mid-2003.

Humira will be studied in a randomized, multicenter, Phase II clinical trial that will assess safety and efficacy in adult patients with moderate to severe chronic-plaque psoriasis. Patient response to treatment will be assessed by using the Psoriasis Area Severity Index score, which is a measure of a patient's disease activity.

Psoriasis is a non-contagious, chronic skin disease characterized by red plaques covered with white scales that presents in different forms and varying degrees of severity. The most common form of psoriasis is "plaque psoriasis," which accounts for approximately 80 percent of psoriasis cases. Plaque psoriasis can appear on any skin surface, although the knees, elbows, scalp, and trunk are the most common locations.

A Phase III study has been initiated that will evaluate Humira in improving signs and symptoms of psoriatic arthritis in adult patients with moderate to severe disease. Patients in the trial will be randomized to receive Humira or placebo, and responses will be measured by improvements in signs and symptoms as measured by American College of Rheumatology response scores.

Flares and remissions characterize the course of psoriatic arthritis, which is an autoimmune disease. If left untreated it can be a progressively disabling disease. The arthritic manifestations often include not only debilitating disease of the hands and feet as is seen in rheumatoid arthritis, but also arthritis of the spine and painful inflammation of tendon insertions. Epidemiological studies indicate that psoriatic arthritis affects as many as 30 percent of the people who have psoriasis. Common symptoms include varying degrees of psoriasis activity along with stiffness, pain, swelling and tenderness of the joints that can lead to a reduced range of motion and potential severe joint destruction.

Humira was discovered through a broad scientific collaboration between Abbott and Cambridge Antibody Technology (CAT). As part of the collaboration, Abbott had the right to select several target antigens for which a joint Abbott/CAT research team would discover human antibody therapeutics. Humira was isolated and optimized by Abbott and CAT as part of this collaboration. Abbott owns exclusive worldwide rights to Humira, including responsibility for clinical development, manufacturing, sales and marketing. Abbott will book all revenues for Humira, and CAT will receive a royalty fee based on Humira sales.