One Year Post-Launch of Argenx's Vyvgart for gMG, US Neurologists Confused on Best Approach to Treatment Dosing Schedules, According to Spherix Global Insights

Despite early satisfaction with Vyvgart, half of surveyed neurologists & neuromuscular specialists report uncertainty regarding re-dosing after the first treatment cycle

EXTON, Pa., Feb. 24, 2023 /PRNewswire/ -- Argenx's launch of Vyvgart (efgartigimod) has been a success, with global first-year revenue of ~$400 million USD. As the second biologic approved for generalized myasthenia gravis (gMG) and the first neonatal Fc receptor (FcRn) blocker, Vyvgart's novel and targeted mechanism of action has resonated with HCPs. Indeed, neurologists and neuromuscular specialists surveyed by Spherix Global Insights consider Vyvgart to address a substantial unmet in the treatment of this chronic, rare autoimmune condition.

Despite these positive perceptions of argenx's brand, surveyed respondents (n=69) remain less confident in Vyvgart's dosing profile. While its infusion administration is familiar and the same as other approved biologics for gMG – Alexion's Soliris and Ultomiris – unlike these brands, it offers somewhat of a flexible dosing schedule. As per the label – and supported by data from its Phase 3 ADAPT trial – Vyvgart is administered as four (4) infusions one (1) week apart, followed by a treatment free period, with additional treatment cycles initiated as needed based on clinical evaluation.

Interestingly, even with increased experience among neurologists, half continue to report uncertainty as to when to re-dose patients after the first Vyvgart treatment cycle. Indeed, when probed unaided on Vyvgart's biggest disadvantages, two in five offered its dosing profile as a leading disadvantage.  Specifically, respondents reported:

• "Re-treatment time is left at discretion of reoccurrence of symptoms, which involves a subjective report from the patient."
  
  
• "I get some push back on the frequency of infusions. Not always sure how to know when the next infusion should be."
  
  
• "Uncertainty how dosed after first round."
  
  
• "Expensive, infusions are too frequent and unclear when to re-dose."
  

This finding was further corroborated during qualitative interviews with Vyvgart prescribers, with one neurologist specifically recalling mixed feelings about Vyvgart's flexible dosing:

"The hassle with Vyvgart, I mean, now, we're gaining experience, but the flexibility in dosing may be a good thing or a bad thing. I'm just accepting it for what it is. But in time, I may have other feelings about it. I may like it a lot, or I may hate it just because of the close monitoring you would need to do with patients."

When put into context, the next question is whether upcoming launches could capitalize on questions around Vyvgart flexible dosing – questions that are likely to linger with the expected approval of argenx's subcutaneous efgartigimod in June 2023, given that it will likely have similar flexible dosing.

Within the FcRn blocker class, UCB's rozanolixizumab is first up with a PDUFA date also in Q2 2023; other potential upcoming launches in the class, while further out, include Janssen's nipocalimab. Outside of this class, other contenders that could threaten argenx's gMG franchise include Genentech's Enspryng (satralizumab) and Horizon's Uplinza (inebilizumab), both of which are already approved for NMOSD and currently in late-phase development for gMG. Neurologists' early view on the pipeline reveals that Enspryng and Uplinza are already of high interest, largely due to their dosing frequencies, distinct mechanisms of action, and potential efficacy.

Spherix will track the evolution of the gMG market through multiple services in 2023. With the expected launches of subcutaneous efgartigimod and rozanolixizumab, Spherix will track the impact of these brands in the US gMG market through its Launch Dynamix™ service. Additionally, insights on inline and pipeline assets, as well as remaining unmet needs in gMG, will be assessed in both the US and EU through research with general neurologists and specialists in the Market Dynamix™ service. The inaugural RealWorld Dynamix™ service will explore the gMG patient journey, including line of therapy, drivers of brand choice, potential next switches, and candidate patient profiles for emerging therapies.

Spherix's 2023 gMG Publication Plan: Click here to view the 2023 gMG publication plan.

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 Market Dynamix™

Market Dynamix™ is an independent service providing analysis of markets anticipated to experience a paradigm shift within the next three to five years. Insights highlight market size, current treatment approaches, unmet needs, and expert opinions on the likely disruption introduced by pipeline agents.

About RealWorld Dynamix™

RealWorld Dynamix™ is an independent, data-driven service unveiling real patient management patterns through rigorous analysis of large-scale patient chart audits. Insights reveal the "why" behind treatment decisions, include year over year trending to quantify key aspects of market evolution, and integrate specialists' attitudinal & demographic data to highlight differences between stated and actual treatment patterns.

About Spherix Global Insights

Spherix Global Insights is a leading provider of market research, business intelligence and advisory services to the global life sciences industry. The company's unique service offerings are powered by deep therapeutic knowledge, the Spherix Network specialty physician panel, and commercially relevant analyses to enable strategic decision-making by our valued customers.

A trusted advisor and industry thought leader, Spherix Global Insights provides specialized market expertise in six (6) focused therapeutic areas including: dermatology, gastroenterology, nephrology, neurology, rheumatology and ophthalmology.

To learn more about Spherix Global Insights, visit spherixglobalinsights.com or connect through LinkedIn and Twitter.

Spherix Global Insights Contacts

Emma McFadden, Senior Insights Director, Neurology
[email protected] 

Scott Upham, Corporate Communications
[email protected]

_{NOTICE: All company, brand or product names in this press release are trademarks of their respective holders. The findings and opinions expressed within are based on Spherix Global Insight's analysis and do not imply a relationship with or endorsement by any company, brand, or product aforementioned.}

SOURCE Spherix Global Insights