B-lymphocyte stimulator benefits SLE using novel combined response endpoint

Belimumab - an inhibitor of soluble B-lymphocyte stimulator - has been shown in phase II studies to produce a sustained improvement in systemic lupus erythematosus (SLE) disease activity.Presenting at the annual meeting of the European Congress of Rheumatology Professor Ellen Ginzler (University of New York) comments that clinical variety of SLE makes it difficult to use a single index to adequately assess therapeutic responses.Therefore, the group used a new combined responder index to assess whether 449 phase II trial subjects responded to belimumab. This combined index defined a response as an improvement of at least four on the SELENA SLEDAI (SS) score with no new British Isles Lupus Assessment Group (BILAG) 1A or 2B flares and no Physician's Global Assessment (PGA) worsening (less than a 0.3-point increase).All participants had SS scores >4 and were randomised to belimumab (1, 4, 10 mg/kg) or placebo to standard of care therapy. Overall, 71.5% of participants had baseline serology of ANA >1:80 or anti-dsDNA Ab >30 IU and were evaluated for response to treatment by SS, the PGA, the BILAG scale, and the Health Questionnaire Short Form 36 (SF-36).Among patients in the belimumab group, the average reduction in SS was 29%, compared with placebo (p=0.044) at week 52; increasing to an average of 38% at week 76. There were also significant Improvements in PGA and SF-36 physical component score (PCS) scores (p=0.001 and pSuccessful treatment using the combined response index was achieved in 46% of those on belimumab and 29% of those on placebo (p=0.006), increasing to 56% of those on belimumab at 76 weeks.Responders had a greater reduction in activated B-cells (36% vs 20%) and anti-dsDNA (53% vs 38%) than non-responders (p"Belimumab treatment resulted in sustained improvement of SLE disease activity, PGA, SF-36 PCS and biomarkers and fewer BILAG flares" Professor Ginzler's group comment.They add that combining multiple disease activity measures into a combined response endpoint improves assessment of disease activity and is predictive of biomarker and quality of life improvements.Reference...