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.