Shares for Argenx soared over 13% Monday morning after the company announced positive data from a Phase 3 trial for a rare autoimmune condition that could expand use of its blockbuster drug Vyvgart.
The Dutch biopharmaceutical company said Monday an under-the-skin injection version of Vyvgart, called Vyvgart Hytrulo, met its primary endpoint in a late-stage combined study of people with myositis, a rare autoimmune disease that attacks the muscles and has limited treatments. The company said that Vyvgart, when compared to placebo, showed improvements in two subsets of the disease, as measured by a scale evaluating muscle strength and physical health known as Total Improvement Score, or TIS.
“For people living with myositis, the goal is straightforward: regain strength and function, and get off long-term steroids. Until now we have had limited targeted therapies to offer patients,” said Rohit Aggarwal, the co-director of the Myositis Center at the University of Pittsburgh and an ALKIVIA investigator, in a statement.
The study enrolled people with two forms of myositis known as dermatomyositis, or DM, which leads to skin rash, and immune-mediated necrotising myopathy, or IMNM, a more aggressive form of the disease that breaks down muscle cells with no approved treatment options, and an approximate patient population of 20,000.
When compared to placebo, Vyvgart displayed “rapid and sustained benefit” starting as early as week four in adults with the condition and lasting a year with steroid tapering. Vyvgart also demonstrated a 15.4-point greater improvement in mean TIS after 52 weeks, according to Argenx. Safety was consistent with prior studies.
Results were driven by strong efficacy data in those with the IMNM form of myositis. And while Vyvgart displayed similar meaningful improvement in those with DM, it did not reach statistical significance.
However, those results did not prompt investors to falter. Leerink Partners analyst Thomas Smith told clients in a note Monday the results are “a positive outcome representing a meaningful expansion opportunity for the Vyvgart franchise, particularly in the IMNM subset where there are no approved therapies and profound unmet need.”
The blockbuster Vyvgart has made Argenx one of biotech’s most valuable companies, with a market capitalization now topping $60 billion. The drug, which reduces the antibody immunoglobulin G, gained its first clearance for the treatment of the autoimmune condition generalized myasthenia gravis, or gMG, in 2021. The drug has since been formulated as a subcutaneous injection and gained label expansion in another autoimmune condition, generating billions for Argenx and, so far this year, climbing close to $2.9 billion between January and June.
Argenx has been on a mission to expand the drug’s use, but has already faced setbacks in other conditions.
The latest study results now provide another expansion opportunity for Vyvgart, with RBC Capital Markets analyst Luca Issa calling the trial a “big win” for the company. Issa added in a note Monday that while the drug missed its primary goal in DM, he believes the drug missed because of small sample size, and will ultimately gain approval “either on this trial or a new larger trial replicating this evidence should the FDA decide to play hard ball.”
Argenx said detailed results will be presented at an upcoming medical meeting.
