The rheumatoid arthritis (RA) market has come a long way since Enbrel (etanercept, Amgen Inc.) was first approved to treat the disease in 1998. Nearly two decades later, there are now a handful of additional TNF-alpha inhibitors, including some long-acting varieties, and multiple other drugs working through different mechanisms of action that have been approved by the FDA to treat RA. In addition to the multitude of biologics, there's even an oral disease-modifying antirheumatic drug (DMARD), Xeljanz (tofacitinib, Pfizer Inc.) that works by inhibiting Janus kinase (JAK).