Advances in molecular biology have led to the development of biologic therapies. This is particularly relevant in systemic lupus erythematosus (SLE), which is a multisystem autoimmune rheumatic disease (ARD) associated with potentially life-threatening complications if not adequately treated. The availability of new biologic drugs has improved the prognosis of SLE in selected cases associated with unsatisfactory response to conventional therapies. Over the last decade, there have been developments in the availability of biologic agents for SLE treatment based upon the advances in the understanding of the disease pathogenesis. Even if the evidence of biologic treatment efficacy in SLE is weaker than in other autoimmune rheumatic diseases, such as rheumatoid arthritis (RA), significant progress was made, as the first biologic treatment for use in SLE patients received approval in 2011. These new biologic therapies for SLE range from anti-CD20/CD22 (clusters of differentiation characteristic to B cells), to anti-B cell activating factors and anti-interferon alpha (IFNα). This chapter reviews the various biologic agents used in SLE, their mechanism of action and safety profile. The most common side effects to biologic treatments include infection, tuberculosis (TB) reactivation and allergic reactions. Less common side effects include development of lymphoma and anti-drug or autoimmune antibody formation. Despite their toxicity profile, biologic agents are gaining ground in clinical practice due to the limited efficacy or increased toxicity of conventional disease modifying agents (DMARD’s). Biologic therapies targeting B cells, such as rituximab, and B cell activation factors, such as belimumab, are currently used in the treatment of refractory SLE. Furthermore, aggressive treatment, including the use of biologic agents, reduces long-term complications associated with prolonged use of steroids in SLE, such as cardiovascular disease and osteoporosis. In the short term, the biologic agents are expensive when compared to traditional DMARDs; however there is evidence that their use is associated with long term benefits for patients with SLE, such as reduced hospital admission and disease complications, and improved patient outcomes. This chapter provides a summary of most biologic agents tested in SLE patients, considering their efficacy and safety profile, as well as the health implications associated with their use. We also take a brief look at newer agents currently investigated in clinical trials
