Spherix Analyzes Reviews of gMG Therapies, Vyvgart, Ultomiris

The two treatments were rated well for effectiveness, but differed in dosing schedule, safety profile

Lindsey Shapiro, PhD avatar

by Lindsey Shapiro, PhD |

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Neurologists find both Vyvgart (efgartigimod) and Ultomiris (ravulizumab-cwvz) effective for treating generalized myasthenia gravis (gMG), but believe Ultomiris has a more convenient dosing schedule while Vyvgart may have a better safety profile.

That’s according to a recent analysis by the market intelligence firm Spherix Global Insights. Spherix’s analysis of the two treatments was part of Launch Dynamix, a service that provides monthly benchmarks of new products during the first 18 months that they’re commercially available.

Both Vyvgart and Ultomiris earned U.S. approval within the past year for treating gMG patients who have antibodies against the acetylcholine receptor (AChRs), the most common MG-causing antibodies.

Even though they’re approved for the same indication, the two treatments have different mechanisms of action.

Argenx’s Vyvgart is designed to block a protein called neonatal Fc receptor (FcRn) that normally helps stabilize antibodies circulating in the bloodstream, including those involved in MG attacks. By doing so, the therapy aims to accelerate the destruction of MG-causing antibodies and ease symptoms.

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Efgartigimod as Injection Similar to Vyvgart in Treating gMG, Trial Finds

Ultomiris works by blocking a critical protein in the body’s complement system involved in driving the inflammatory damage seen in MG. It was originally developed by Alexion Pharmaceuticals, which was acquired by AstraZeneca last year.

Spherix reported in a press release that neurologists in the U.S. noted Vyvgart’s effectiveness and safety as its greatest advantages for treating gMG, whereas Ultomiris’ advantages were its effectiveness and convenient dosing schedule.

The dosing of Ultomiris was deemed more convenient than Vyvgart’s. After an initial loading dose, Ultomiris is delivered as an into-the-vein infusion every eight weeks.

“I definitely like the every-eight-week dosing interval. It takes the guesswork out of it,” a neurologist said.

Vyvgart is administered as an infusion once weekly over a four-week treatment cycle. Subsequent treatment cycles are determined based on clinical evaluations.

“The bad thing is it’s kind of like an as-needed medication,” one neurologist said. “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.”

But Spherix noted Vyvgart outperforms Ultomiris in overall safety. Ultomiris comes with a boxed warning for serious meningococcal infections that can quickly become life-threatening if not treated. Vyvgart has not been associated with a similar risk. In the U.S., Ultomiris is only available through a restricted access program called ULTOMIRIS REMS.

Some neurologists who were interviewed indicated they didn’t find that warning to be a significant deterrent to Ultomiris’ use, which was sometimes attributed to their past experience prescribing Soliris (eculizumab), another approved gMG treatment that comes with a similar infection warning. Similarly, the REMS program was not seen as a major deterrent to using Ultomiris.

Whether a patient was comfortable with the medication’s safety risks significantly influenced neurologists’ prescribing decisions.

Some interviewees also noted the safety profile of Vyvgart may be different in clinical practice than it was in the Phase 3 ADAPT Phase trial (NCT03669588) that supported its approval.

“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,” a doctor said. “The re-treatment criteria were way too strict … Therefore the safety data is not valid for the way it’s going to be used.”

Nevertheless, Vyvgart was generally deemed to fulfill an unmet need for gMG patients, and its use is expected to expand significantly in the next six months, Spherix said.

An under-the-skin injectable formulation of Vyvgart is expected to launch in 2023.