Correspondence on 'Interleukin 6 receptor inhibition in primary Sjogren syndrome

We read with interest the correspondence related to the article ‘Interleukin 6 receptor inhibition in primary Sjogren syndrome: a multicentre double-blind randomised placebo-controlled trial’ in which possible explanations for negative findings in recent phase III randomised controlled trials (RCTs) for primary Sjogren’s syndrome (pSS) are discussed, including the RCT with tocilizumab.1–3 This is an important issue to raise, since there is still an unmet need for effective treatment in pSS. As discussed in these letters,2 3 most recent RCTs used the European League Against Rheumatism (EULAR) Sjogren’s Syndrome Disease Activity Index (ESSDAI) as primary endpoint. The ESSDAI is widely applied and seems suitable to assess systemic disease activity in clinical practice and in cohort studies in a standardised way. However, there are some limitations to the ESSDAI as primary endpoint in trials.4 In addition to the points made by our colleagues, it is important to note that in several RCTs, including the tocilizumab trial, large response rates for the ESSDAI minimal clinically important improvement (≥3 points decrease) were seen in both the active treatment …