The current focus of treatment in primary Sjögren's syndrome (SS) is symptom management. Since SS is an autoimmune disease with multisystem involvement, systemic immunosuppression may have a role in improving signs and symptoms and preventing progression. We undertook this review to assess the efficacy and safety of immunomodulation on primary SS from randomized clinical trials (RCTs).
Five electronic databases (Medline, Embase, Central, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform) were searched to include RCTs for the treatment of SS. Primary outcome measures included ocular dryness, oral dryness, tear production, and salivary function. Serious adverse events (AEs) and withdrawals due to AEs were also assessed.
The search yielded 32 trials evaluating 19 different medications. The average duration of diagnosis was long (up to 9.2 years). Twenty-two trials examined ocular and oral dryness, for which only 2 and 4 trials showed statistically significant improvements, respectively. No studies found a benefit for tear production; few studies found improvements for unstimulated salivary flow (3 of 16 RCTs) and stimulated salivary flow (2 of 14 RCTs). Meta-analysis at 6 months found improvements as compared to placebo for unstimulated salivary flow (P = 0.003) and a decrease in the erythrocyte sedimentation rate (P = 0.007). No differences were seen for serious AEs, but there were increased withdrawals from AEs (risk ratio 2.33; P = 0.03).
Reducing inflammation potentially improves salivary gland function. No individual immunomodulatory drug demonstrated a consistent benefit in xerostomia and xerophthalmia. Further work is needed to identify SS patients with an ability to improve and with outcomes that are valid and sensitive to change within clinical trials. Tradeoffs in the future between benefit and safety may also be important, because more withdrawals occurred with active treatment.