Argenx Trial Success
Argenx Shares Surge as Vyvgart, Hytrulo Show Positive Phase 3 Results for Autoimmune Diseases
Key Points
ADAPT OCULUS enrolled 141 patients across North America, Europe and Asia-Pacific; Vyvgart given subcutaneously achieved a mean MGII PRO improvement of 4.04 points at Week 4 versus 1.99 for placebo, with no new safety concerns and a safety profile consistent with prior studies, supporting a planned sBLA to expand the label to ocular myasthenia gravis.
Argenx shares rose about 8% in early trading to 788.40 euros, and were up roughly 10% year-to-date, reflecting broad investor optimism around the trial readouts.
Luc Truyen, Argenx's Chief Medical Officer, said the patient response to efgartigimod was durable and multidimensional, with separation from placebo emerging early and persisting through a full year of treatment.
Analysts from KBC Securities noted that Argenx plans to pursue an accelerated approval for IMNM and will discuss a potential filing for dermatomyositis with US health authorities.
Argenx shares jumped roughly 8% to 788.40 euros after the Belgian biotech reported strong phase 3 results for its drug efgartigimod (Vyvgart) in autoimmune myositis — a rare muscle disease with no approved treatments. MarketScreener reported the stock was also up about 10% year-to-date, reflecting growing investor confidence in the company's pipeline.
The ALKIVIA trial showed patients receiving VYVGART Hytrulo gained a 15.4-point advantage over placebo on a standard muscle function score at 52 weeks. Investing.com reported the drug met its primary endpoint across patients with immune-mediated necrotizing myopathy (IMNM) and dermatomyositis (DM) — two serious forms of the disease.
IMNM Results Strong, DM Falls Short on Statistics
In IMNM patients, efgartigimod produced a 14.8-point improvement over placebo on the Total Improvement Score (TIS). The TIS measures how much a patient's muscle strength, function, and symptoms improve. That gap was both statistically significant and clinically meaningful, according to Grafa.
In dermatomyositis patients, the drug showed a 14.5-point improvement over placebo — nearly as large. But the result was not statistically significant, likely because the DM group was smaller. MarketScreener noted that Argenx plans to discuss a potential DM filing with US regulators and will seek accelerated approval for the IMNM indication.
Drug Worked Fast and Kept Working for a Full Year
One of the most striking findings was how quickly the drug worked. Patients started separating from placebo as early as Week 4 of treatment. That early effect then held steady through the full 52-week study period.
Luc Truyen, Argenx's Chief Medical Officer, said the patient response was "durable and multidimensional." He added that the separation from placebo emerged early and persisted through a full year of treatment. Grafa also reported consistent improvements across all patient subgroups in the ALKIVIA trial.
Vyvgart Eyes New Label for Ocular Myasthenia Gravis
Argenx also released data from a separate trial called ADAPT OCULUS. That study enrolled 141 patients across North America, Europe, and Asia-Pacific. It focused on ocular myasthenia gravis (oMG) — a condition where the eye muscles weaken and cause drooping eyelids and double vision.
Patients receiving Vyvgart subcutaneously showed a 4.04-point improvement on a patient-reported eye symptom score at Week 4. The placebo group improved by just 1.99 points. No new safety concerns appeared, and the safety profile matched earlier studies. Investing.com reported Argenx plans to file an sBLA — a supplemental drug application — with the FDA to expand Vyvgart's label to cover oMG.
Analysts See Path to Multiple New Indications
Analysts from KBC Securities said the results open a clear regulatory path. Argenx plans to pursue accelerated approval for IMNM and will hold talks with US health authorities about filing for DM. Both moves could add major new revenue streams for a drug already approved for other autoimmune diseases.
MarketScreener noted the trial data could support new indications across multiple autoimmune conditions — strengthening Vyvgart's position as a broad platform drug. Efgartigimod works by lowering harmful antibodies that attack the body's own tissues, a mechanism that applies to a wide range of autoimmune diseases.
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