Belimumab--an anti-BLyS human monoclonal antibody for rheumatoid arthritis.

INTRODUCTION: B lymphocyte stimulator (BLyS) is a major regulatory factor that controls the development and survival of B cells. Elevated serum levels of BLyS have been associated with rheumatoid arthritis (RA). Belimumab is a fully human monoclonal antibody that inhibits BLyS and it is being developed for the treatment of RA. This review aims to summarize up-to-date pharmacological and clinical data of belimumab in the treatment of RA. AREAS COVERED: A literature search was performed on PubMed using keywords, including belimumab, LymphoStat-B, benlysta, BLyS inhibitor, rheumatoid arthritis and autoimmune disease. References of relevant studies were searched by hand. Abstracts of international conferences up to October 2012 were also included. Belimumab was well tolerated in the treatment of RA over 24 weeks. It significantly increased American College of Rheumatology (ACR)20 responses at week 24, especially in patients with high disease activity, positive rheumatoid factor, no anti-TNF treatment experience and those who had failed methotrexate therapy. However, belimumab failed to demonstrate significantly improved ACR50 and ACR70 responses in the single Phase II clinical trial of RA. EXPERT OPINION: These results suggest that the clinical efficacy of belimumab for RA needs to be further investigated in future clinical trials. Careful patient selection may be necessary for belimumab to achieve optimal clinical outcomes in RA.