Abatacept: A Review of the Treatment of Polyarticular-Course Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) encompasses several forms of chronic inflammatory arthritis of unknown etiology presenting in children < 16 years of age, with a minimum symptom duration of 6 weeks. Approximately half of affected children have polyarticular-course JIA (pJIA), a functional concept related to several clinically and genetically heterogeneous JIA categories (systemic, extended oligoarthritis, polyarticular rheumatoid factor-positive or rheumatoid factor-negative, enthesitis-related arthritis, and psoriatic arthritis), which has as its defining feature the involvement of five or more joints during the disease course. Chronic inflammation and joint damage lead to the manifestations of JIA such as pain, limitation of motion, and loss of physical function, all of which negatively impact patients’ quality of life. The American College of Rheumatology recommends initial treatment with a conventional synthetic disease-modifying antirheumatic drug (csDMARD), such as methotrexate (MTX) and, in patients with pJIA who have an inadequate response or intolerance to MTX, the use of a biologic DMARD (bDMARD) such as a tumor necrosis factor inhibitor, abatacept, or tocilizumab. Abatacept selectively modulates the CD80/CD86:CD28 co-stimulatory signal required for full T cell activation, and thus has a distinct mechanism of action upstream of that of other currently available bDMARD treatments for rheumatic diseases. To enable physicians to make informed treatment decisions, it is important to review available data for the existing therapeutic agents. Here, we summarize the current evidence from phase III pivotal trials of intravenous (IV) and subcutaneous (SC) abatacept and from an ongoing registry of patients with JIA treated with abatacept. In the pivotal trials for IV and SC abatacept, either with or without MTX, both formulations demonstrated clinical efficacy, with a high proportion of patients achieving stringent clinical responses, as well as improvements in patient-reported outcomes and a favorable safety profile, particularly with regard to infections.