Editorial: Epratuzumab: Reveille or Requiem? Teachable Moments for Lupus and Sjögren's Syndrome Clinical Trials

Targeted Therapy for Primary Sjögren's Syndrome: Where are We Now?

Primary Sjögren's syndrome (pSS) is an autoimmune exocrinopathy characterized by dryness symptoms. This review briefly describes recent advances in the targeted therapies for pSS. Biologics evaluated for pSS treatment mainly include B cell-depleting agents, inhibitors of B cell activation, and agents that target co-signaling molecules or proinflammatory cytokines. Small molecule inhibitors that target signaling pathways have also been evaluated. However, current evidence for the efficacy of targeted therapies in pSS is still sparse. Although ianalumab (an anti-B cell-activating factor [BAFF]-receptor antibody) and iscalimab (an anti-CD40 antibody) are promising biologics for pSS, their efficacy still needs to be evaluated in larger clinical trials. For other biologics, clinical trials have found no differences versus placebo in the change from baseline in European League Against Rheumatism Sjögren's Syndrome Disease Activity Index (ESSDAI) score and fatigue score. Possible causes of the disappointing outcomes mainly include the inefficacy of those evaluated biologics in treating pSS, the high heterogeneous nature of pSS, irreversible exocrine glandular failure at advanced disease stages, inappropriate recruitment strategy in clinical trials, and outcome measures. Early diagnosis and glandular function-centered outcome measures may help to improve the current situation in the systemic therapy of pSS.

Lessons learned from the failure of several recent trials with biologic treatment in systemic lupus erythematosus

INTRODUCTION

Treatment of systemic lupus erythematosus (SLE) represents a challenge due to variable disease manifestations, clinical course, and outcome. Long-term outcome in SLE remain unsatisfactory and a search for new therapeutic options is definitely warranted. Despite expectations, most clinical trials performed in SLE and lupus nephritis in the last decade did not reach primary outcome, and the only drug that has been licensed is belimumab.

AREAS COVERED

Results of negative trials testing monoclonal antibodies and other biologic agents in SLE are briefly summarized. Reasons for the failure of the trials are listed and discussed.

EXPERT OPINION

Future studies should recruit patients with similar organ involvement, better defined disease manifestations, higher activity, and similar severity. In addition to testing higher efficacy if given as add-on treatment to standard-of-care, the trials should be aimed at reducing dosing, or completely eliminating some parts of the current standard treatment, especially corticosteroids. Median follow-up of the patients should be longer. Moreover, specific biomarkers are needed to help to identify eligible patients and to better define response to treatment. An urgent unmet need is testing these new drugs in patients with severe SLE (including those refractory to current treatment).