Amgen and Wyeth Pharmaceuticals, a division of Wyeth announced the initiation of the largest clinical trial to date to evaluate the impact of a Tumor Necrosis Factor (TNF) inhibitor in patients with rheumatoid arthritis (RA) in the United States.

This second phase of a 10,000-patient study known as RADIUS (Rheumatoid Arthritis DMARD Intervention and Utilization Study) will compare the safety, efficacy and treatment patterns of 5,000 RA patients treated with Enbrel (etanercept) with that of 5,000 patients treated with a variety of disease modifying anti-rheumatic drugs (DMARDs) in the first phase.

"This study will improve the quality of information on which practicing rheumatologists base their treatment decisions," said Dr. Allan Gibofsky, professor of medicine and public health at the Weill Cornell Medical College and an independent advisor to the study.

RADIUS will evaluate patients who meet American College of Rheumatology (ACR) criteria for RA, and who require a change or addition of a new DMARD. Enbrel will be used in eligible patients either as monotherapy or in addition to the patient's current DMARD treatment. Investigators in over 450 study sites will conduct the study and data will be collected for at least five years.

"Rheumatologists have treated over 129,000 patients with Enbrel and have four years of post-marketing experience, so they are already very familiar with its benefits in treating RA and with its proven long-term safety profile," said Dr. Daniel Burge, Amgen's vice president of clinical research. "We are excited to draw from this experience and learn more about the use of Enbrel in a real world setting."

The drug used to initiate RADIUS 2 was produced in a new manufacturing facility for Enbrel located in Rhode Island. This facility is under review by the U.S. Food and Drug Administration.