An Agency for Healthcare Research and Quality executive summary indicated that better comparative effectiveness trial designs are needed to determine the relative merits of existing versus new and expensive biologic drug therapies for rheumatoid arthritis (RA). There are now 9 biologic therapies approved for treating RA. Four classes of biologics (TNF antagonists, B-cell inhibitors, T-cell co-stimulator blocker, and Interleukin-6 receptor blocker) are approved for use in RA patients with moderate or severe disease activity. Several critical questions have arisen, such as 1) what therapy should be prescribed after failure of methotrexate and/or other oral disease modifying antirheumatic drugs (DMARDs) to adequately control disease activity; 2) what is the level of efficacy of the various biologic therapies when compared in head-to-head trials; and 3) what are the mechanisms associated with failure of methotrexate and/or other oral DMARD therapy and responsiveness to biologic therapies. The MAZERATI study will provide the foundation for answering these questions and determining the mechanisms associated with these biologic therapies.