RHO study supports proof-of-concept in primary Sjogren's disease

Decision informed by favorable safety profile and consistency across efficacy and biomarker measures

March 27, 2024, 7:00 AM CET

Amsterdam, the Netherlands – argenx SE (Euronext & Nasdaq: ARGX), a global immunology company committed to improving the lives of people suffering from severe autoimmune diseases, today announced its plan to continue the development of efgartigimod to Phase 3 in adults with primary Sjogren's disease (SjD), following the analysis of topline data from the Phase 2 RHO study. Detailed results will be presented at a future medical meeting.

"We are excited to be advancing efgartigimod's development in Sjogren's disease based on the totality of the data generated from the RHO study," said Luc Truyen, M.D., Ph.D., Chief Medical Officer of argenx. "Consistent with our indication selection strategy, we confirmed our IgG biology hypothesis with these data, and now have a demonstrated clinical effect across multiple efficacy scales to support proof-of-concept. Sjogren's disease can be debilitating, predominantly affects women, and given its heterogeneous nature, is often misdiagnosed with its symptoms poorly understood. With no current approved therapies to treat the underlying disease, the unmet need is substantial, and we recognize the opportunity to advance a new potential alternative treatment to these patients."

The decision to advance the clinical development of efgartigimod in SjD was supported by the safety, efficacy and biomarker results from the study. The observed safety and tolerability profile was consistent with other clinical trials. Efficacy assessments showed a treatment effect across multiple clinical endpoints, which were also consistent with biomarker data.

RHO Study Design

The Phase 2 RHO study was a randomized, double-blinded, placebo-controlled multicenter proof of concept study to evaluate the safety and efficacy of VYVGART in adults with SjD. In order to enter the study, patients needed to test positive for anti-Ro autoantibodies and maintain residual salivary flow. Thirty four patients were randomized 2:1 to receive either efgartigimod or placebo for up to 24 weeks. Multiple endpoints and biomarkers were evaluated in the signal-finding study, including the primary endpoint of CRESS (Composite of Relevant Endpoints for Sjogren's Syndrome). Within CRESS there are five components spanning: systemic disease activity as measured by the ESSDAI (EULAR Sjogren's Syndrome Activity Index), patient reported outcomes as measured by the ESSPRI (EULAR Sjogren's Syndrome Patient Reported Index), tear and salivary gland function and serology. To be a CRESS responder, patients needed to demonstrate a clinically meaningful benefit in at least 3 of the 5 composite items. Additional datapoints were gathered including the clinESSDAI, STAR (Sjogren's Tool for Assessing Response), biomarker data, and the change in lymphocytic infiltrate levels through parotid biopsies.