Tumor necrosis factor (
TNF) antagonists have dramatically improved the outcomes of
rheumatoid arthritis (RA). Three agents currently available in the USA--
infliximab,
etanercept, and
adalimumab--have been designed to modify the
biologic effects of TNF.
Infliximab and
adalimumab are
monoclonal antibodies, and
etanercept is a soluble
protein. The pharmacokinetic and pharmacodynamic properties of each differs significantly from those of the others. All three agents are effective and safe, and can improve the quality of life in patients with RA. Although no direct comparisons are available, clinical trials provide evidence that can be used to evaluate the comparative efficacy of these agents.
Infliximab, in combination with
methotrexate, has been shown to relieve the signs and symptoms of RA, decrease total joint score progression, prevent joint erosions and joint-space narrowing, and improve physical function for up to 2 years.
Etanercept has been shown to relieve the signs and symptoms of RA, decrease total joint score progression, and slow the rate of joint destruction, and might improve physical function.
Etanercept is approved with and without
methotrexate for patients who have demonstrated an incomplete response to
therapy with
methotrexate and other disease-modifying
anti-rheumatic drugs (DMARDs), as well as for first-line
therapy in early RA,
psoriatic arthritis, and juvenile RA.
Adalimumab relieves the signs and symptoms of RA with and without
methotrexate and other DMARDs, decreases total joint score progression, prevents joint erosions and joint-space narrowing in combination with
methotrexate, and might improve physical function. When selecting a
TNF antagonist, rheumatologists should weigh evidence and experience with specific agents before a decision is made for use in
therapy.