Argenx's Vyvgart launch finds quick neurologist support over AstraZeneca's well-entrenched Soliris for myasthenia gravis

Argenx nabbed an FDA approval for its rare disease drug Vyvgart just before Christmas and is wasting no time launching the generalized myasthenia gravis (gMG) med and setting it up to compete with AstraZeneca's Soliris.

Vyvgart marks the biopharma's first ever regulatory green light, while Soliris won its FDA nod for gMG back in 2017 and was the crown jewel of AstraZeneca's $39 billion buyout of Alexion, a deal first announced in December 2020. 

But while Soliris has several years of a head start on Vyvgart and is well entrenched, Argenx's speedy launch is already paying dividends, it seems. A new report out from Spherix found that more than half (51%) of the surveyed U.S. neurologists perceived Vyvgart “to offer a substantial advance over other currently available therapies.”

Argenx's field team had mobilized in late December, soon after approval, and Vyvgart along with its direct-to-consumer advertising has already launched, its CEO Tim Van Hauwermeiren said in a January interview with Fierce Pharma.

RELATED: Argenx snags first FDA approval with Vyvgart win in generalized myasthenia gravis

The DTC campaign's TV ad is titled simply “New Treatment Option” and focuses heavily on a new FDA-approved treatment option but does not call out Vyvgart by name. Argenx is also tapping patients’ voices, tweeting out a video of a gMG sufferer talking about the difficulties of living with the disease.

Argenx's sales and marketing strategy appears to be paying off. Among the 72 U.S. neurologists Spherix surveyed, under half (44%) of those who had prescribed Vyvgart scored their satisfaction with the drug as “high” and 56% as “moderate.” GMG has a prevalence of around 14 to 20 per 100,000. It is a chronic autoimmune, neuromuscular disease that causes weakness in the skeletal muscles. Soliris is a C5 complement inhibitor, while Vyvgart is a neonatal Fc receptor blocker.

Vyvgart has already “commanded a sizeable prescriber base” the report found, despite there being limited patients due to its rarity. When the survey was undertaken in early February, Vyvgart's market share among biologic drugs for gMG was 2.9% while Soliris' was 12.3%, the report found.

And the good news keeps coming, as although Vyvgart is argenx’ first commercial launch, sales representatives have already engaged with half of surveyed neurologists, Spherix said, which “has helped fuel high brand awareness.” 

But Spherix did find that neurologists are sitting on a “wait and see” attitude towards rating the execution of the company's commercial roll out. Month-over-month trends “will help illuminate how effectively Argenx is able to compete with big pharma on support and outreach,” the firm said.

Nonetheless, Spherix predicts that in six months Vyvgart will sit at 18.6%,  a lead—albeit a thin one—over Soliris, which will be at 18.5%.

Soliris made $1.8 billion for AstraZeneca last year, although it is also approved for paroxysmal nocturnal hemoglobinuria (PNH) to reduce hemolysis and for patients with atypical hemolytic uremic syndrome. Soliris costs $470,000 annually in the gMG setting, a price which was criticized by the Institute of Clinical and Economic Review last summer, while Vyvgart costs around $225,000, though that comes after weight-based dosing for both drugs and value-based arrangements with payers.

AstraZeneca is already lining up its next-gen, long-acting C5 complement inhibitor Ultomiris as a follow-up to Soliris, which starts to lose patent protection from 2027. So far, Ultomiris has an FDA nod for PNH.

RELATED: AstraZeneca's newly acquired Soliris is overpriced in myasthenia gravis, cost watchdog says

Argenx, for its part, is hoping Vyvgart will be a “pipeline in a product” given the new indications it will be gunning for. In the near term, it has five phase 3 trials reading out in the next four quarters. First up, a subcutaneous formulation of efgartigimod in MG is due to deliver results in the first quarter.

The quarter after that, Argenx is expecting a readout of the first of two registration trials in immune thrombocytopenia, and then the pemphigus readout in the fourth quarter followed by data in chronic inflammatory demyelinating polyradiculoneuropathy in the first three months of 2023.

It’s not a surprise that Van Hauwermeiren has designs for the drug to help Argenx become an “immunology powerhouse” in the future.

Both drugs may also soon have another contender to deal with as UCB is also gunning to file for a U.S. approval of its late-stage FcRn candidate rozanolixizumab later this year. It is also working on a C5 inhibitor, known as zilucoplan, which has an FDA orphan drug tag.