Study underscores the relative safety of infliximab, when used properly

Rheumatoid arthritis patients receiving the recommended starting dose (3mg/kg) of infliximab (REMICADE®) have no more serious rate of infections than do patients taking methotrexate alone; however, patients undergoing induction and treatment with a high dose have more problems with infections, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in San Antonio, Texas.

Biologic disease-modifying antirheumatic drugs (DMARDs), like infliximab, have been given to more than 700,000 people worldwide since their introduction in 1998. These drugs, designed to suppress the inflammation associated with rheumatoid arthritis, have been shown to reduce the signs and symptoms of rheumatoid arthritis, improve physical function and inhibit the progression of joint damage to the joints. But, as is true of any medication that affects the immune system, a concern with this class of medications is that they may increase the risk of infections.

To evaluate the risk of serious infections associated with the use of infliximab plus methotrexate relative to placebo, researchers conducted a year-long multinational double-blind study on 1,082 patients in 12 countries.

Patients were randomized into one of three groups using a 1:1:1 ratio (placebo/methotrexate n=363; 3 mg/kg infliximab plus methotrexate arm n=360; 10 mg/kg infliximab plus methotrexate arm n=361). Group one received placebo for the first 22 weeks, crossing over to 3mg/kg every eight weeks of infliximab up through week 54. Group two was given a dose of 3mg/kg of infliximab at the outset and weeks two and six, followed by every eight weeks until week 22. The dose was then increased by increments of 1.5mg/kg every eight weeks if needed. Group three received a dose of 10mg/kg (outset, weeks two and six, followed by every eight weeks) throughout the length of the study. All patients also received methotrexate through the course of the study.

Findings demonstrated that over the course of a year, the relative risk of serious infection with infliximab given at the recommended induction and maintenance regimen of 3mg/kg was similar to placebo, even though some patients had their dose escalated in the second half of the study. However, infliximab given at the higher induction and maintenance regimen of 10mg/kg was associated with an increased risk of serious infections.

"This study underscores the relative safety of infliximab, when used properly," said David Yocum, MD, University of Arizona, Tucson, and an investigator in the study. "With careful monitoring, more rheumatoid arthritis patients can safely realize the significant benefits of biologic anti-rheumatic therapy."

The American College of Rheumatology is the professional organization for rheumatologists and health professionals who share a dedication to healing, preventing disability and curing arthritis and related rheumatic and musculoskeletal diseases.

For more information on the ACR's annual meeting, see http://www.rheumatology.org/annual.