European Committee Recommends Efgartigimod Approval for gMG

Lindsey Shapiro, PhD avatar

by Lindsey Shapiro, PhD |

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European regulators have recommended efgartigimod be approved as an add-on therapy for adults with generalized myasthenia gravis (gMG) who have anti-acetylcholine receptor (AChR) antibodies.

This recommendation, from the Committee for Medicinal Products for Human Use (CHMP), will serve as the basis for a final regulatory decision from the European Commission. That decision is expected within about two months and will apply to all European Union member states in addition to Iceland, Norway, and Liechtenstein, Argenx, the therapy’s developer, reported.

Efgartigimod is approved in the U.S. and sold under the brand name Vyvgart for the same indication as that proposed for Europe, and in Japan for patients who respond poorly to other therapies, regardless of AChR antibody status.

“We are thrilled by the CHMP’s recommendation in favor of efgartigimod, which brings us one step closer to delivering this therapy to people living with gMG in Europe and around the world,” Anant Murthy, PhD, Argenx’s EU general manager, said in a press release. “We are confident in the European team we have built, and pending marketing authorization, look forward to close collaboration with regulatory bodies and government authorities across the region to ensure this treatment option will be available for as many patients as possible.”

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gMG is caused by the immune system mistakenly producing self-reactive antibodies that attack proteins required for nerve-muscle communication, most commonly AChRs.

Delivered directly into the bloodstream, efgartigimod works by inhibiting the neonatal Fc receptor, which normally acts to prevent antibodies circulating in the bloodstream from degrading. In doing so, efgartigimod aims for gMG-causing antibodies to be broken down more quickly, lowering their levels and easing symptoms.

The application submitted by Argenx to European regulatory bodies included data from the pivotal Phase 3 ADAPT trial (NCT03669588), which were published in The Lancet Neurology last summer.

ADAPT evaluated the safety and effectiveness of efgartigimod (10 mg/kg) against a placebo in 167 adult gMG patients in North America, Europe, and Japan over 26 weeks (about six months).

After a first treatment cycle consisting of four weeks of a single weekly infusion, patients received an individualized treatment approach with a variable number of treatment cycles according to their own clinical response. All participants remained on their other gMG treatments during the trial.

Top-line data demonstrated efgartigimod led to sustained declines in symptom severity among patients with AChR antibodies compared with the placebo group, meeting the trial’s main goal.

Specifically, 68% of treated patients with AChR antibodies saw sustained clinical improvements on the Myasthenia Gravis Activities of Daily Living (MG-ADL) scale during the first treatment cycle, compared with 30% of those in the placebo group. Similarly, 63% of treated patients improved on the Quantitative Myasthenia Gravis (QMG) scale, compared with 14% of placebo-treated patients.

Positive clinical responses were also seen among patients without AChR antibodies.

Efgartigimod was generally well-tolerated, with the most commonly reported side effects being upper respiratory tract infections and urinary tract infections, occurring in 10.7% and 9.5% of treated patients, respectively.

Most participants from ADAPT entered its open-label extension, ADAPT-Plus (NCT03770403), which is evaluating the therapy’s safety and tolerability for up to three years. It’s expected to conclude in 2o23.

If approved, efgartigimod will be the first neonatal Fc receptor blocker available for adults with gMG in Europe.

“The current treatment of generalized MG in Europe leaves many patients with insufficiently controlled symptoms that markedly decrease quality of life,” Anthony Béhin, MD, a neuromusuclar physician at the Institut de Myologie, La Pitié Salpétrière, Paris, said.

“Caregivers and medical teams are well aware of the need for new treatment options that are safe, effective and targeted to the disease biology. As a practicing neurologist regularly seeing people who live with this debilitating chronic disease, the CHMP’s positive opinion of efgartigimod represents an exciting advancement toward bringing a new treatment option to these patients in Europe,” Béhin said.

Argenx also plans to launch efgartigimod in Canada and other regions, and the company’s partner, Zai Lab, is planning to seek approval in China.