Spherix Global Insights

August 24, 2022

Argenx’s Vyvgart and Alexion’s Ultomiris Go Toe-to-Toe in Generalized Myasthenia Gravis, According to Spherix Global Insights

Positive perceptions for both brands will drive expansion of patient share and prescriber base

EXTON, Pa., August 24, 2022/ PRNewswire/ – Competition in the generalized myasthenia gravis (gMG) market is heating up with the launches of argenx’s Vyvgart and Alexion’s Ultomiris earlier this year. Both brands have the same approved indication but differ on mechanism of action, dosing profiles, and safety (among other factors). Spherix recently carried out a deep dive into neurologists’ use and perceptions of the disease modifying therapies as part of the ongoing Launch Dynamix™: Vyvgart (argenx) and Ultomiris (Alexion) in gMG (US) service.

Six months into the launch of Vyvgart, neurologists identified (unaided) the brand’s efficacy and safety as its greatest advantages for the treatment of gMG. For Ultomiris, efficacy is also as a top advantage of the drug, in addition to its convenient dosing schedule. One interviewed neurologist reported, “I definitely like the every-eight-week dosing interval. It takes the guesswork out of it.”

Indeed, neurologists report a slight edge for Ultomiris over Vyvgart on favorable dosing, and at this early stage of Vyvgart’s launch, some have questions on the drug’s treatment schedule.

As noted by one respondent, “The bad thing is it’s kind of like an as-needed medication. After you give the first cycle, then you have to wait and see if there’s deterioration. Sometimes patients get nervous. I can get nervous, especially in a patient who when they do deteriorate, they immediately go into crisis. That’s why I choose my patients as to who I should give it to.”

Conversely, argenx’s neonatal fragment crystallizable receptor (FcRn) blocker well outperforms Ultomiris on overall safety, with Alexion’s C5 complement inhibitor having a black box warning for serious meningococcal infections – a feature not shared by Vyvgart. Interestingly, some interviewed neurologists did not perceive Ultomiris’ black box warning or its REMS program to be a major deterrent to use of the brand – in part because of their previous experience with Alexion’s Soliris. However, other neurologists did acknowledge that patients’ comfort level with Ultomiris’ safety risks does influence their prescribing decisions and not all patients are willing to accept those risks.

With some neurologists’ expectation that Vyvgart dosing in clinical practice will be more frequent than in the ADAPT Phase III clinical, one respondent noted that Vyvgart’s safety in the real world might not mirror trial safety data:

“The biggest concern I have is about the safety: we are absolutely, 100% going to be giving the drug [Vyvgart] more often than what was given in the clinical trial because I think they didn’t conduct their studies the way they should have. The re-treatment criteria were way too strict…Therefore the safety data is not valid for the way it’s going to be used.”

Despite these concerns, neurologists have overall welcomed the addition of Vyvgart as a new treatment option for gMG and view the brand’s unique mechanism of action as fulfilling an unmet need for patients. Indeed, Vyvgart’s patient share is expected to increase significantly in the next six months, coupled by expansion in its prescriber base. The launch of a subcutaneous version, expected in 2023, will likely further drive argenx’s gMG franchise.

About Launch Dynamix™
Launch Dynamix™ is an independent service providing monthly benchmarking of newly launched products for the first eighteen months of commercial availability, augmented by a quarterly deep dive into promotional activity, barriers to uptake, and patient types gravitating to the launch brand.

About Spherix Global Insights
Spherix Global Insights is a hyper-focused market intelligence firm that leverages our own independent data and expertise to provide strategic guidance, so biopharma stakeholders make decisions with confidence. We specialize in select immunology, nephrology, and neurology markets.

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