Utilization of biologic agents in rheumatoid arthritis in the United States: analysis of prescribing patterns in 16,752 newly diagnosed patients and patients new to biologic therapy.

BACKGROUND: Treatment of rheumatoid arthritis (RA) has shifted toward earlier and more aggressive therapy with tra- ditional disease-modifying antirheumatic drugs (DMARDs) and biologics. However, the extent to which these agents are used in current clinical practice in the United States (U.S.) has not been systematically evaluated.

MATERIALS AND METHODS: This analysis of a large claims database assessed patterns of use of biologics within clinical practice in a broad U.S. population with RA. We identifed two cohorts of adults with RA using Thomson Healthcare MarketScan Research databases. Patients newly diagnosed with RA between 1999 and 2004 with 12 months or more of continuous enrollment prior to diagnosis and with 24 months or more post-diagnosis were included in one cohort. The second cohort included RA patients who appeared to be newly treated with biologic therapy and had continu- ous enrollment for 12 months or more prior to frst use of a biologic agent and 18 months or more following initial treatment. A total of 16,752 patients, newly diagnosed with RA, and 8218, new to biologics therapy, were included.

RESULTS: Utilization of biologics increased from 3% of patients in 1999 to 26% in 2006. Patients initiated biolog- ics both as monotherapy (30%) and in combination with methotrexate (36%). Regimen modifcations were frequent, with a large percentage of patients requiring addition or subtraction of methotrexate.

CONCLUSIONS: The use of biologics to treat RA is increas- ing, either as monotherapy or in combination with another DMARD. Modifcations to drug regimens are frequent and episodes are often of comparatively short duration.