Belimumab reduces autoantibodies, normalizes low complement levels, and reduces select B cell populations in patients with systemic lupus erythematosus.

OBJECTIVE: To assess the effects of the B lymphocyte stimulator (BLyS)-specific inhibitor belimumab on immunologic biomarkers, including B cell and T cell populations, and maintenance of antibody titers to prior vaccines in autoantibody-positive systemic lupus erythematosus (SLE) patients. METHODS: Pooled data from 2 phase III trials, the Study of Belimumab in Subjects with SLE 52-week (BLISS-52) and 76-week (BLISS-76) trials, comparing belimumab 1 mg/kg or 10 mg/kg versus placebo (plus standard SLE therapy for each group) were analyzed for changes in autoantibody, immunoglobulin, and complement levels. BLISS-76 patients were also analyzed for changes in B cell and T cell populations and effects on prior vaccine-induced antibody levels. RESULTS: Belimumab-treated patients experienced significant sustained reductions in IgG and autoantibodies and improvement in C3/C4 levels, resulting in greater positive-to-negative conversion rates for IgG anti-double-stranded DNA (anti-dsDNA), anti-Sm, anticardiolipin, and anti-ribosomal P autoantibodies and normalization of hypergammaglobulinemia and low C3/C4 levels. Belimumab-treated patients experienced significant decreases in the numbers of naive and activated B cells, as well as plasma cells, whereas memory B cells and T cell populations did not decrease. Belimumab did not substantially affect preexisting antipneumococcal or anti-tetanus toxoid antibody levels. Post hoc analysis showed greater reductions in SLE disease activity and the risk of severe flares in patients treated with belimumab 10 mg/kg (P≤0.01) who were anti-dsDNA positive and had low C3/C4 levels at baseline. Normalization of the C3 or anti-dsDNA level by 8 weeks, irrespective of therapy, was predictive of a reduced risk of severe flare over 52 weeks. CONCLUSION: Belimumab appears to promote normalization of serologic activity and reduce BLyS-dependent B cell subsets in serologically and clinically active SLE. Greater serologic activity may predict a better treatment response to belimumab.

Effect of belimumab on vaccine antigen antibodies to influenza, pneumococcal, and tetanus vaccines in patients with systemic lupus erythematosus in the BLISS-76 trial.

OBJECTIVE: In patients with systemic lupus erythematosus (SLE), evidence suggests that most vaccines (except live-virus vaccines) are safe, although antibody response may be reduced. This substudy from the phase III, randomized, double-blind, placebo-controlled BLISS-76 trial evaluated the effects of belimumab on preexisting antibody levels against pneumococcal, tetanus, and influenza antigens in patients with SLE. METHODS: In BLISS-76, patients with autoantibody-positive, active SLE were treated with placebo or belimumab 1 or 10 mg/kg every 2 weeks for 28 days and every 28 days thereafter, plus standard SLE therapy, for 76 weeks. This analysis included a subset of patients who had received pneumococcal or tetanus vaccine within 5 years or influenza vaccine within 1 year of study participation. Antibodies to vaccine antigens were tested at baseline and Week 52, and percentage changes in antibody levels from baseline and proportions of patients maintaining levels at Week 52 were assessed. Antibody titers were also assessed in a small number of patients vaccinated during the study. RESULTS: Consistent with preservation of the memory B cell compartment with belimumab treatment, the proportions of patients maintaining antibody responses to pneumococcal, tetanus, and influenza antigens were not reduced. In a small group receiving influenza vaccine on study, antibody responses were frequently lower with belimumab, although titer levels were > 1:10 in all patients treated with 10 mg/kg and in the majority treated with 1 mg/kg. CONCLUSION: Treatment with belimumab did not affect the ability of patients with SLE to maintain antibody titers to previous pneumococcal, tetanus, and influenza immunizations. [ClinicalTrials.gov registration number NCT 00410384].

Efficacy and safety of rituximab in moderately-to-severely active systemic lupus erythematosus: the randomized, double-blind, phase II/III systemic lupus erythematosus evaluation of rituximab trial.

OBJECTIVE: B cells are likely to contribute to the pathogenesis of systemic lupus erythematosus (SLE), and rituximab induces depletion of B cells. The Exploratory Phase II/III SLE Evaluation of Rituximab (EXPLORER) trial tested the efficacy and safety of rituximab versus placebo in patients with moderately-to-severely active extrarenal SLE. METHODS: Patients entered with >or=1 British Isles Lupus Assessment Group (BILAG) A score or >or=2 BILAG B scores despite background immunosuppressant therapy, which was continued during the trial. Prednisone was added and subsequently tapered. Patients were randomized at a ratio of 2:1 to receive rituximab (1,000 mg) or placebo on days 1, 15, 168, and 182. RESULTS: In the intent-to-treat analysis of 257 patients, background treatment was evenly distributed among azathioprine, mycophenolate mofetil, and methotrexate. Fifty-three percent of the patients had >or=1 BILAG A score at entry, and 57% of the patients were categorized as being steroid dependent. No differences were observed between placebo and rituximab in the primary and secondary efficacy end points, including the BILAG-defined response, in terms of both area under the curve and landmark analyses. A beneficial effect of rituximab on the primary end point was observed in the African American and Hispanic subgroups. Safety and tolerability were similar in patients receiving placebo and those receiving rituximab. CONCLUSION: The EXPLORER trial enrolled patients with moderately-to-severely active SLE and used aggressive background treatment and sensitive cutoffs for nonresponse. No differences were noted between placebo and rituximab in the primary and secondary end points. Further evaluation of patient subsets, biomarkers, and exploratory outcome models may improve the design of future SLE clinical trials.

14. Immunologic rheumatic disorders.

We provide the basics for the clinician who might be called on to consider the diagnosis of diseases such as systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA) in their practice. We will emphasize clinical recognition and first-line laboratory testing. Only characteristics of the classic rheumatic inflammatory diseases, RA, SLE, Sjögren syndrome, scleroderma, and dermatomyositis/polymyositis, will be covered. In the past decade, RA is the only disease for which treatment has substantially improved. The treatment of RA has been revolutionized by the use of methotrexate and, more recently, tumor necrosis factor inhibitors. The goal of RA treatment today is to induce a complete remission as early as possible in the disease process, with the mantra being "elimination of synovitis equals elimination of joint destruction." The hope is that if the major mediators of Sjögren syndrome or SLE or scleroderma can be identified and then blocked, as in the example of tumor necrosis factor inhibitors in RA, more specific treatments will become available. Thus, RA has become an excellent model of this evolving paradigm. Through the identification of major mediators in its pathogenesis, novel and highly efficacious therapeutic agents have been developed.