Belimumab: a BLyS-specific inhibitor for systemic lupus erythematosus.

OBJECTIVE: To review the efficacy, safety, dosing, drug interactions, as well as economic and therapeutic considerations of belimumab, an investigational B-lymphocyte stimulator (BLyS) inhibitor.

DATA SOURCES: A systematic, English-language MEDLINE search (1966-August 2010) was conducted using the search terms belimumab, Benlysta, B-lymphocyte stimulators, BLyS-specific inhibitors, and systemic lupus erythematosus (SLE). Press releases and bibliographies were reviewed for additional information and citations.

STUDY SELECTION AND DATA EXTRACTION: Belimumab was first identified and studied as a human protein target in 1999. Therefore, all published clinical trials and abstracts evaluating the safety and efficacy of belimumab for treatment of SLE as well as review articles from 1999 to present were evaluated for inclusion. Additional data were extracted from the manufacturer's Web site and Food and Drug Administration (FDA) documents.

DATA SYNTHESIS: Current therapies for SLE target nonspecific sites for inflammatory reduction and immune system suppression. Belimumab is a target-specific, human IgG1λ monoclonal B-lymphocyte stimulator inhibitor currently in late stage investigation for the treatment of SLE. Unpublished Phase 3 trials have reported statistically significant results for primary endpoints when belimumab 10 mg/kg plus standard of care was compared to placebo plus standard of care in seropositive patients with SLE. Overall, belimumab has been relatively well tolerated with discontinuation rates and adverse events similar to those of placebo. If belimumab is approved by the FDA, its US market launch would be expected in 2011.

CONCLUSIONS: Belimumab has shown significant benefits for patients with SLE in the few Phase 3 trials that have been published. However, questions remain regarding optimal patient population, duration of treatment, place in therapy, and long-term adverse effects.