Belimumab, a monoclonal anti-B lymphocyte Stimulator (BLyS) antibody, appeared effective in Sjögren's syndrome (SS) in the phase II open-label 52-week BELISS study. Herein, the follow-up after the end of the BELISS study and suspension of the drug was reported in order to further verify the efficacy of belimumab in SS.
13 SS patients were followed after the end of the belimumab treatment. The patients were all female, aged 54±15 years; all the patients presented anti-SSA and/or anti-SSB positivity. Composite scores for SS disease activity were collected at month 6 and month 12 after the end of the trial. The changes of IgG, IgA, IgM immunoglobulin serum levels, and rheumatoid factor (RF) level were reported. BLyS serum levels were also analysed. Statistics for paired comparisons were used.
ESSDAI score increased from 3.5±3.7 at week 52 (end of the trial) to 7.0±5.7 at month 12 after the end of the trial (p=0.003). RF level increased from 31.0 (8.0-224.6) IU/ml at week 52 to 69 (11-666) IU/ml at month 12 after the end of the trial (p=0.008). IgM level increased from 131.9±73.6 mg/dl at week 52 to 165±84.6 mg/dl at month 12 after the end of the trial (p=0.04). A significant increase of serum BLyS levels also increased from 1304 (667-3835) pg/ml at week 52 to 2882 (1353-6178) pg/ml twelve months after belimumab suspension (p=0,04).
Targeting BLyS by belimumab appears effective in SS, with the inhibition of RF-positive B cell proliferation.