Argenx posts J&J-rivaling Sjögren's data, massively upscales Vyvgart patient population at R&D day

Even as argenx begins to chart a course toward a future beyond Vyvgart, the company’s flagship FcRn inhibitor still has plenty of tricks in store for the remainder of the decade.

By 2030, argenx is aiming to have five new preclinical assets in phase 3 development, 10 approved indications across Vyvgart and other near-term prospective launches, and 50,000 patients on therapy across current and future argenx products, the company said at an R&D day Tuesday. The plan has been dubbed “Vision 2030: Taking Breakthrough Science to 50,000 Patients.”

While up-and-coming candidates like the C2 scavenger antibody empasiprubart and ARGX-121 are certainly expected to contribute to argenx’s growth in the coming years, Vyvgart—which won its original nod in generalized myasthenia gravis (gMG) in late 2021 and another in chronic inflammatory demyelinating polyneuropathy (CIDP) this summer—still has an outsized role to play in the company’s burgeoning success story.

For one, argenx has drastically overhauled its projection for the total addressable gMG market. The company now figures the market opportunity for Vyvgart has swelled to 42,000 patients, up from an original estimate of 17,000, analysts at Citi wrote in a note to clients.

Argenx credits that market growth to the expansion of biologics share in gMG, plus the increasing use of Vyvgart in earlier lines of therapy. What’s more, argenx figures it could snare another 11,000 seronegative and 7,000 ocular gMG patients through potential label expansions to bring its total addressable population up to roughly 60,000.

Argenx is currently marketing Vyvgart for gMG in the U.S., Canada and multiple European countries, as well as China and Japan. The company also has Vyvgart distribution deals in places like the Middle East and Eastern Europe.

As for Vyvgart’s CIDP launch, the drug has so far reached two patients, according to a note from analysts at William Blair. One of those patients was commercial, while the other’s medication was reimbursed by Medicare.  

According to the William Blair team, argenx is actively working through formulary placements with payers and expects prior authorization and coverage denial headwinds to improve as these are finalized. Despite some initial hurdles with the rollout, the William Blair team said that “early underlying demand appears strong” in CIDP.

To hear analysts at Citi tell it, meanwhile, over 25% of key CIDP physician targets were reached within the first two weeks of Vyvgart’s launch. Argenx said it’s seeing early adoption and noted that doctors have written prescriptions for multiple CIDP patients. At the same time, roughly 20% of those doctors are first-time Vyvgart prescribers, suggesting an “early expansion of the Vyvgart prescriber base,” according to the Citi team.

In argenx’s final Vyvgart trick of the day, the company also posted positive phase 2 data in Sjögren's disease (SjD), where Johnson & Johnson recently found midstage success with its own phase 2 candidate nipocalimab.

Argenx’s data provide “encouraging validation for the FcRn mechanism in Sjogren’s,” the team of Citi analysts said, adding that argenx plans to kick off a phase 3 trial of Vyvgart in SjD by year-end. Analysts at Leerink Partners, for their part, said argenx’s SjD data were “encouraging” and “appear competitive” versus J&J’s.

Argenx first telegraphed plans for the new Vision 2030 program in mid-June.

“[A]rgenx today is better positioned than ever before to deliver on our commitment to transform the autoimmunity treatment landscape for patients,” CEO Tim Van Hauwermeiren said in a statement at the time. “We have grown from our R&D roots over the last five years into a true global innovator, pioneering novel targets into a robust pipeline and delivering safe and effective first-in-class medicines to more than 10,000 patients around the world.”