Infliximab treatment of rheumatoid arthritis and Crohn's disease.

OBJECTIVE

To review the pharmacology, pharmacokinetics, efficacy, safety, and pharmacoeconomic impact of infliximab in the treatment of Crohn's disease (CD) and rheumatoid arthritis (RA).

DATA SOURCES

MEDLINE and Pre-MEDLINE (1966-June 2002) and manufacturer prescribing literature were employed to find English-language articles on infliximab. Additional studies and abstracts were identified from the bibliographies of reviewed literature and conference proceedings.

STUDY SELECTION/DATA EXTRACTION: All articles identified from data sources were evaluated, and all information deemed relevant was included in this review. Information regarding basic pharmacology was collected from studies in animals. Pharmacokinetic data were collected from human trials. Safety data were extracted from clinical trials and postmarketing surveillance. Priority was given to randomized, double-blind, placebo-controlled studies for the assessment of efficacy. All available economic evaluations were included.

DATA SYNTHESIS

Infliximab is a new monoclonal antibody that appears to work by a unique mechanism: inhibiting the action of tumor necrosis factor-alpha (TNF-alpha). Infliximab is administered by intravenous infusion. In clinical trials in CD, infliximab significantly decreased the CD activity index compared with placebo in treatment-resistant disease and significantly reduced the number of draining fistulas in fistulizing disease. In RA, when infliximab was added to methotrexate (MTX), it resulted in a significant improvement in most disease outcome measures when compared with MTX plus placebo. Few major adverse effects were reported in the clinical trials; however, serious adverse events, including malignancy and demyelination, have been reported in postmarketing surveillance. Also, increased susceptibility to infections (including tuberculosis) has been reported.

CONCLUSIONS

Infliximab is an effective new agent for the treatment of CD and RA. Its apparent unique mechanism of action makes infliximab an important addition to therapy. Caution should be exercised when considering infliximab for individuals who have chronic or recurrent infections, mild congestive heart failure (New York Heart Association [NYHA] class I/II), nervous system disorders, or live or have lived in an area endemic for histoplasmosis. Infliximab is contraindicated for patients with a clinically important, active infection, moderate to severe congestive heart failure (NYHA class III/IV), or an allergy to mouse proteins or any of the ingredients in infliximab. Further long-term efficacy, safety, and economic data on infliximab are required. Also, for the treatment of RA, the burden of administering infliximab (as a 2-hour supervised infusion) has to be considered when choosing among anti-TNF-alpha medication (as the other 2 approved agents, etanercept and adalimumab, can be self-administered by subcutaneous injection).