In this review, we summarise the clinical efficacy and safety of B-cell targeted therapies for primary Sjögren's syndrome (pSS).
A systematic literature review was conducted using databases including MEDLINE, EMBASE and Cochrane. Only articles reporting controlled or prospective studies of b-DMARDs modulating B cells in treatment of pSS were selected. The highest-quality studies were selected for meta-analysis. The primary outcome of interest was clinical efficacy at week 24 on fatigue, dryness, Schirmer test, salivary flow rate and the full ESSDAI score including biological domain. For the efficacy criteria used, the difference between rituximab and placebo groups was expressed as mean difference (MD).
Eighteen articles (13 of rituximab, 3 of belimumab, 1 of epratuzumab and 1 of baminercept) were identified for detailed evaluation. 4 controlled randomised trials of rituximab treatment vs. placebo involving 300 patients were included for quantitative analysis. No significant differences were observed between groups in the meta-analysis of mean improvements between baseline and week 24 in fatigue VAS [MD -3,24 95% CI (-30,21 to 23,72)], oral dryness VAS [MD -8,41 95% CI (-35,06 to 18,24)], salivary flow rate [MD 0,04 95% CI (-0,03 to 0,11)] and Schirmer test [MD 0,35 95% CI (-2,13 to 2,82)]. Rituximab was relatively safe compared to placebo.
Our review shows that rituximab is not effective in pSS with the designs and outcomes proposed in the trials. Controlled randomised trials are needed to prove the efficacy of belimumab and epratuzumab in this indication. The randomised controlled trial evaluating baminercept failed to achieve its primary endpoint.