From its initial nod in generalized myasthenia gravis (gMG) in 2021 to a subcutaneous approval this summer—and now, a stellar showing in a second neuromuscular disease—Argenx’s flagship drug Vyvgart is proving its merit as a potential franchise.
In the latest victory for Argenx, Vyvgart Hytrulo—the subcutaneous version of the company’s autoimmune med—came out on top in a study of adults with chronic inflammatory demyelinating polyneuropathy (CIDP), slashing the risk of relapse 61% over placebo.
Further, 67% of patients in the open-label Stage A arm of Argenx’s ADHERE trial showed evidence of clinical improvement, validating the company’s hypothesis that immunoglobulin G (IgG) type antibodies play a significant role in the underlying biology of CIDP.
CIDP is a rare autoimmune disease of the peripheral nervous system that causes fatigue, muscle weakness and loss of feeling in patients’ arms and legs. That weakness may worsen over time or come and go, with the potential for symptoms to significantly impair a person’s ability to function day-to-day. Without treatment, one-third of people living with CIDP will need a wheelchair, Argenx points out.
The disease affects about 16,000 people in the U.S.
ADHERE, meanwhile, represents the largest clinical trial of CIDP patients to date, Argenx said. The study—which will be presented in full at an upcoming medical meeting—enrolled both treatment-naïve adults as well as those currently on immunoglobulin therapy or corticosteroids.
According to Argenx’s chief operating officer, Karen Massey, Vyvgart Hytrulo has the potential to “ignite a real paradigm shift” as “the first innovation in the treatment of CIDP in 30 years.”
Current standard of care, Massey said on a conference call Monday, comes with “many trade-offs” that in turn present Argenx with an “opportunity for transformative change.”
Aside from efficacy and safety perks demonstrated in the ADHERE study, Argenx is pitching Vyvgart Hytrulo’s potential convenience edge over standard CIDP therapy, which Massey noted costs patients “long hours in the infusion chair.”
Vyvgart, by comparison, boasts “high-speed administration” and is given as a speedy 30- to 90-second injection.
Massey further highlighted the fact that 91% of patients in Argenx’s trial chose to stick with Vyvgart in the open-label extension portion of the study, which she heralded as “proof of the [drug’s] value proposition for patients.”
Regarding future launch plans, Massey noted that Argenx plans to leverage the infrastructure it’s already built in gMG “across many other neuromuscular diseases.” Plus, the company’s not stopping there: “We will take the learnings around neuromuscular franchises and apply them to our expansion in hematology, dermatology and rheumatology,” the COO added.
Since its initial U.S. approval in December 2021, Vyvgart has racked up successive gMG nods across six regions globally, most recently in China. For all of 2022, the drug brought home $401 million in worldwide sales. And in the first quarter of 2023 alone, the drug managed to reel in $218 million globally, Massey pointed out.
Argenx sees gMG and CIDP as the tip of the iceberg for Vyvgart, which CEO Tim Van Hauwermeiren is aiming at a slate of other autoimmune diseases. Speaking to Fierce Pharma around the drug’s initial green light, Van Hauwermeiren noted there are more than 100 IgG-mediated autoimmune diseases, all of which could be addressed with a neonatal Fc receptor antagonist like Vyvgart.
In the meantime, Vyvgart has continued to build momentum, most recently with a subcutaneous green light in late June. With that nod, Vyvgart Hytrulo became the first below-the-skin injectable for gMG, leveraging Halozyme’s Enhanze drug delivery tech.