Background Biologics used in combination with methotrexate or other non-biologic disease modifying anti-rheumatic drugs (DMARDs) are associated with improved efficacy compared to biologic monotherapy alone in most studies.
Objectives The objective of this analysis was to examine the prevalence of non-biologic DMARD use among Medicare beneficiaries with rheumatoid arthritis (RA) initiating biologic therapies from 2006 to 2009.
Methods Using data from the 100% sample of U.S. Medicare beneficiaries, we identified RA patients (≥2 RA diagnoses from rheumatologist visit between 7 and 365 days apart) who initiated a new biologic. These patients were then categorized into two groups: 1) beneficiaries who were not exposed to any biologic during the preceding 6 months (new users); and 2) beneficiaries who were exposed to a different biologic in the preceding 6 months (switchers). Within each group, we examined the proportion of patients exposed to non-biologic DMARDs within 121 days after initiation of the biologic therapy. The following hierarchy was applied to classify non-biologic DMARD use: any oral methotrexate; any subcutaneous methotrexate; any use of sulfasalazine, hydroxycholoroquine or leflunomide; other non-biologic DMARDs (e.g. gold); and none.
Results: Results We identified 17,662 new users and 13,608 switchers. Among new users, patients initiating etanercept, infliximab, or adalimumab totaled 12,360, accounting for 70% of all new users. Among switchers, they accounted for only 43% (n=5,802). The proportion of new users receiving biologic monotherapy ranged from 24% (infliximab) to 51% (certolizumab). A greater proportion of new infliximab users received oral methotrexate (53%) compared with users of other biologics. Although the same pattern persisted, significantly less variation was observed among switchers; the proportion of switchers receiving monotherapy ranged from 30% (infliximab) to 44% (certolizumab) (Figure).
Conclusions From 2006 to 2009, among Medicare beneficiaries with RA, approximately 25% to 50% of RA patients initiating or switching biologics were not on methotrexate or other DMARDs. Additional research identifying the most effective biologics that can be used as monotherapy appears warranted given the large number of RA patients with this treatment need.
Acknowledgements This work was supported by (R01 HS018517). Dr. Curtis receives support from the NIH (AR 053351).
Disclosure of Interest J. Curtis Grant/research support from: Amgen, Genentech, Consultant for: Amgen, AbbVie, BMS, Pfizer, Janssen, UCB, Roche/Genentech, CORRONA, J. Zhang Grant/research support from: Amgen, Genentech, F. Xie: None Declared, E. Delzell Grant/research support from: Amgen, L. Chen: None Declared, M. Kilgore Grant/research support from: Amgen, H. Yun Grant/research support from: Amgen, K. Saag: None Declared, J. Lewis Grant/research support from: Shire, Centocor, Takeda, Consultant for: Amgen, Millennium, Abbott,