Background Belimumab, a monoclonal antibody against BAFF registered for the treatment of systemic lupus erythematosus (SLE), was recently employed in primary SS in the BELISS trial (1), with encouraging results reported at 6 months of treatment.
Objectives To report the efficacy and safety of long term treatment of Sjögren's syndrome (SS) with belimumab, targeting the B-cell activating factor.
Methods Patients with primary SS were included in this 1-year open-label trial if they were positive for anti-SSA or anti-SSB antibodies and had systemic complications or persistent salivary gland enlargement or early disease or biomarkers of B-cell activation. Efficacy and safety were analyzed during the 1-year period of treatment. Limitedly to the Italian BELISS protocol, to evaluate a possible delayed response, treatment with belimumab could be also continued up to W48 if both the clinician and the patient agreed to complete the study despite the lack of response at W28, but in the absence of clinical worsening or side effects. A final evaluation was scheduled at W52. Response was defined as the improvement in at least 2 of the 5 following items: ≥30% reduction in dryness score on a visual analogue scale (VAS), ≥30% reduction in fatigue score on a VAS, ≥30% reduction in musculoskeletal pain score on a VAS, ≥30% reduction in systemic activity score on a VAS assessed by the physician, and/or ≥25% reduction in serum levels of any of the following B-cell activation biomarkers (free light chains of immunoglobulin, beta2-microglobulin, immunoglobulin monoclonal component, cryoglobulins, IgG) or ≥25% increase in C4 level.
Results Nineteen out of 30 patients terminated the 52-week study, 15 of them being responders while 4 non-responders at W28. Thirteen of the 15 responders at W28 also responded at W52 (86.7%). Overall, fatigue, and pain appeared to improve with time from W28 to W52, although without any statistical significance, while dryness symptoms remained stable. However, a significant improvement in the physician VAS systemic activity score was recorded (3.2±1.2 at W28 vs. 2.5±1.1 at W52; p=0.04). In the 15 responders at W28, the ESSDAI was 7.5±4.0 at baseline, 3.9±3.1 at W28 (p<0.0001 vs. baseline), with a trend of further improvement at W52, i.e., 3.1±3.2 (p<0.0001 vs. baseline). In the same 15 responders, the ESSPRI was 6.0±1.0 at baseline, 4.5±1.8 at W28 (p=0.003 vs. baseline), and 4.3±2.3 at W52 (p=0.01 vs. baseline) (p=0.7, between W28 and W52). A moderate disease activity (i.e., an ESSDAI score ≥5) was observed in 5/15 (33.3%) patients at W52 vs. 6/15 (40%) at W28 and vs. 10/15 (66.7%) at baseline. Decreases of B-cell biomarkers observed at W28 persisted unchanged until W52, with the exception of the rheumatoid factor, which appeared to further decrease [64.8±78.7 IU/mL at baseline, 51.1±56.8 IU/mL at W28 (p=0.028, W28 vs. baseline) and 42.6±47.3 IU/ml at W52 (p=0.048, W52 vs. baseline)]. The safety of treatment was good at W52.
Conclusions Long-term treatment with belimumab may be beneficial in SS. Randomised, controlled studies in larger populations are encouraged.
Mariette X, et al. Ann Rheum Dis 2013.
Disclosure of Interest None declared
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