Response to: ‘Association of subcutaneous belimumab and long-term antimalarial treatment reduces antiphospholipid antibodies levels in systemic lupus erythematosus: post-hoc analysis of a randomised placebo-controlled trial–comment on: ‘Effect of belimumab treatment on antiphospholipid antibody levels: post-hoc analysis based on two randomised placebo-controlled trials in systemic lupus erythematosus’ by Chatzidionysiouet al’ by Bettiolet al

We thank Dr Bettiol et al 1 for their interest in our article.2 Dr Bettiol et al performed a post-hoc analysis on a different randomised controlled trial of subcutaneous belimumab in systemic lupus erythematosus (SLE). The authors evaluated the effect of treatment with belimumab on the levels of anticardiolipin antibodies (aCL) (IgG, IgM and IgA) but also of anti-β2-glycoprotein I (antiβ2GPI) antibodies. The latter was unfortunately not available in BLISS-76 and BLISS-52 trials, as acknowledged in the limitations of our post-hoc analysis. The authors have also extended our observation about the effect of co-treatment with antimalarials on antiphospholipid antibody (aPL) titres in the belimumab versus the placebo group, by examining the duration of their use. We agree with the authors that the duration of antimalarials is of high clinical significance. In addition to previous retrospective studies,3 we have recently shown in …