argenx SE 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. 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. 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. Sjogren?s Disease (SjD) is a chronic, slowly progressive inflammatory systemic autoimmune disease characterized by immune-mediated destruction of exocrine glands.

SjD can be severely debilitating and have a negative impact on patient quality of life, with common symptoms reported as dry eyes and mouth, fatigue, joint point and impaired cognitive function. In addition, a substantial subset of patients suffer from extraglandular systemic disease. While the presence of anti-Ro and anti-LA IgG autoantibodies are considered a hallmark of disease, the underlying cause of SjD is believed to be multi-factorial, triggered by environmental factors, leading to auto-immunity and chronic inflammation.

SjD predominantly impacts women with a 9:1 female:male incidence ratio. Given the heterogeneous nature of the disease, the treatment journey can be challenging with long delays and high rates of misdiagnosis. There are no FDA-approved treatments targeting the disease itself, leaving current treatments to focus primarily on individual symptom management.

Efgartigimod is an antibody fragment designed to reduce pathogenic immunoglobulin G (IgG) antibodies by binding to the neonatal Fc receptor and blocking the IgG recycling process. Efgartigimod is being investigated in several autoimmune diseases known to be mediated by disease-causing IgG antibodies, including neuromuscular disorders, blood disorders, and skin blistering diseases, in both an intravenous and subcutaneous (SC) formulation. Efgartigimod is marketed as VYVGART® for the treatment of generalized myasthenia gravis in more than 30 regions globally and immune thrombocytopenia in Japan.