Amgen’s Enbrel for Psoriasis

On April 30, 2004 Amgen Inc. announced that its biological therapy Enbrel® (etanercept) had received approval from the FDA. The drug is approved for the treatment of psoriasis in adult patients who are candidates for systemic therapy and who suffer from chronic moderate-to-severe plaque psoriasis. This most recent approval adds to Enbrel’s previously approved indications of Rheumatoid Arthritis, Juvenile Rheumatoid Arthritis, Ankylosing Spondylitis, and Psoriatic Arthritis. Amgen reported that the FDA approval was based on data from more than 1,200 adults with plaque psoriasis in two Phase III studies. Patients were treated with a 50 mg dosing regimen of Enbrel twice-weekly for three months followed by a 50 mg weekly maintenance dose for up to 12 months. The company stated that 46% of patients receiving the 50 mg twice-weekly dose achieved the primary endpoint of a 75% or greater improvement in the Psoriasis Area Severity Index (PASI 75) at three months.

Enbrel is a protein that is thought to exert its action through the binding and subsequent inactivation of a naturally produced cytokine known as Tumor necrosis factor (TNF). TNF is produced by the body’s immune system, and in patients with psoriasis and other autoimmune diseases, certain immune cells increase production of TNF. This increased TNF activity is thought to be critical in mediating the overactive immune response that causes the tissue damage that is a hallmark of psoriasis and rheumatoid arthritis. Amgen has indicated that approximately 234,000 patients have already been treated with Enbrel worldwide. Amgen reports total sales of Enbrel for 2003 in the 1.3 billion dollar range

The true incidence of psoriasis in the United States is difficult to determine. Estimates of prevalence suggest that approximately 4.5 million people are affected by psoriasis with approximately one third of these suffering from the ‘plaque’ type of the disease. Psoriasis is characterized by the development of red, itchy skin plaques that are often painful and disfiguring.

Enbrel satisfies all Biohorizon criteria for High Impact Technologies: it is an innovative therapy, it has diffused rapidly, it has demonstrated efficacy in clinical trials, and with this most recent approval, it is indicated for more prevalent conditions. In light of the psoriasis indication, clients should begin or revisit assessment activities at this time.

Technology Details
Target Disease / Indication: Psoriasis
Technology Classification: Drug
Body System: Integumentary System
Program Area: Medicine/Dermatology
Regulatory Status: Approved
BioHorizon Impact Score: 76/100 – High