Efgartigimod shows long-term benefit in Sjögren’s disease study
Small Phase 2 extension found maintained responses up to 72 weeks
Written by |
Efgartigimod, a treatment approved for certain autoimmune diseases, was linked to maintained clinical responses and low disease activity scores for up to 72 weeks in people with Sjögren’s disease, according to data from a small Phase 2 clinical trial and its open-label extension study.
Participants who showed a clinical response on weekly dosing were switched to every-other-week infusions, and responses were generally maintained. The data were presented at the recent European Alliance of Associations for Rheumatology (EULAR) 2026 Congress.
“We are encouraged by the consistency of the long-term data as well as data underscoring efgartigimod’s favorable safety profile across multiple autoimmune … diseases,” Luc Truyen, MD, PhD, chief medical officer at Argenx, the therapy’s developer, said in a company press release. “We are looking forward to additional results evaluating efgartigimod … in Sjogren’s disease next year.”
Phase 3 trial now underway
A global Phase 3 clinical trial, called UNITY (NCT06684847), is now further assessing the efficacy and safety of efgartigimod, given by under-the-skin, or subcutaneous, injections, in a larger group of adults with moderate-to-severe primary Sjögren’s disease. Results are expected in the second half of 2027.
In autoimmune diseases, the immune system mistakenly attacks the body’s own healthy tissues, often driven by self-reactive antibodies. In Sjögren’s, the body’s moisture-producing glands are the main targets of these attacks, leading to symptoms such as dry eyes and mouth, although the joints, nervous system, and other organs can also be affected.
Efgartigimod blocks the neonatal Fc receptor (FcRn), a protein that normally helps keep certain antibodies in the bloodstream, including the self-reactive ones that contribute to autoimmune diseases. This is expected to lower levels of these harmful antibodies and reduce disease activity.
Two formulations of the therapy are approved in the U.S. for adults with generalized myasthenia gravis: an into-the-vein, or intravenous, version sold as Vyvgart, and a subcutaneous version sold as Vyvgart Hytrulo. Vyvgart Hytrulo is also approved for adults with chronic inflammatory demyelinating polyneuropathy, another autoimmune disease.
Argenx is now evaluating efgartigimod’s potential to treat a broader range of autoimmune conditions, including Sjögren’s.
Phase 2 study tested IV efgartigimod
The proof-of-concept Phase 2 RHO clinical trial (NCT05817669) was designed to evaluate the preliminary benefits of efgartigimod for Sjögren’s. It enrolled 34 adults with moderate-to-severe Sjögren’s disease, who received weekly intravenous infusions of either efgartigimod or a placebo for about six months.
Disease activity was measured with the Clinical EULAR Sjögren’s Syndrome Disease Activity Index (ClinESSDAI). Overall treatment responses were assessed with the Composite of Relevant Endpoints for Sjögren’s Syndrome (CRESS), a composite measure that incorporates disease activity, patient-reported symptoms, tear gland function, salivary gland function, and blood levels of disease-related antibodies.
Results showed a numerical difference favoring efgartigimod in CRESS response rates (45.5% vs. 11.1%) and reductions in certain immune markers compared with a placebo. However, because this was a small proof-of-concept study, the findings were considered preliminary.
Participants who completed RHO could then enter its open-label extension study, RHO-plus (NCT06203457), in which all initially received weekly intravenous efgartigimod for up to 48 weeks. Participants who met ClinESSDAI-assessed response criteria were switched from weekly to every-other-week dosing.
Newly presented data concerned the 17 participants who had Week 48 assessments in RHO-plus and were included in the efficacy analysis, including 13 who continuously received efgartigimod and four who switched from the placebo.
The results showed that those continuously receiving efgartigimod generally maintained clinical responses they had achieved in the original study, including after switching from weekly to every-other-week dosing, according to Argenx.
For those who switched from a placebo to efgartigimod, clinical improvements were observed in ClinESSDAI, along with higher CRESS response rates.
Low disease activity seen at 72 weeks
According to the abstract submitted for presentation, in a post hoc analysis comparing Week 48 results with the start of RHO, 38% of participants who continuously received efgartigimod were considered CRESS treatment responders, as were 75% of those who switched from the placebo.
After 72 weeks, spanning the RHO and RHO-plus studies, ClinESSDAI scores in both groups reflected low disease activity, defined as scores lower than five, with a median of 2.5 in those continuously receiving efgartigimod and 2.0 in the placebo-to-efgartigimod group.
Efgartigimod was well tolerated, with no new safety signals identified, Argenx reported.
The ongoing Phase 3 UNITY study is comparing efgartigimod against a placebo in 631 adults with moderate-to-severe primary Sjögren’s disease, with the main goal of evaluating changes in ClinESSDAI scores after about a year.
In another presentation, researchers reported that efgartigimod had a consistent safety profile across multiple clinical trials, encompassing 834 patients with autoimmune diseases. Most adverse events were mild or moderate, and their rates did not increase with longer treatment use.
“Our presentations at EULAR further support the rationale for targeting FcRn in autoimmune rheumatic diseases and underscore its potential to address significant unmet patient need,” Truyen said.
Leave a comment
Fill in the required fields to post. Your email address will not be published.