Established medications. New areas of application

During the last 10 years several new medications from hemato-oncology and transplantation medicine have been transferred to rheumatology. Additionally, medications which are approved for rheumatoid arthritis were increasingly also studied and used for other systemic inflammatory rheumatic diseases. This is especially the case for rituximab and mycophenolate and to a lesser extent also for leflunomide, tumor necrosis factor (TNF) antagonists, tocilizumab and abatacept. Recently, rituximab was approved for severe granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) after the publication of two prospective randomized trials in 2010. The situation concerning rituximab is much more problematic for systemic lupus erythematosus (SLE) where randomized placebo-controlled trials exist but unfortunately did not meet the primary endpoint requirements (too many highly effective additional forms of treatment in both arms and unsuitable endpoints), although data from registries suggest efficacy especially in cases resistant to treatment. In the case of mycophenolate (MPS) the problem with SLE is totally different. All prospective trials met the endpoints and in one trial MPS was even superior to azathioprine for treatment of lupus nephritis (LN) which led to the recommendation of MPS for induction and maintenance in LN by EULAR and EDTRA as well as more recently by the ACR. However, MPS still is not approved for SLE or LN. The present manuscript gives an overview of existing data for selected connective tissue diseases and vasculitides (for which at least larger retrospective case series or registry data exist) being treated with medications approved for other indications.