Argenx Highlights gMG Drug Data in CIDP

Rare Daily Staff

Argenx said that positive data from its phase 3 ADHERE trial evaluating Vyvgart Hytrulo in patients with chronic inflammatory demyelinating polyneuropathy were presented for the first time to the medical community during the Clinical Trials Plenary Session at the American Academy of Neurology Annual Meeting in Denver.

Argenx also highlighted clinical trial and real-world data across seven posters and presentations that continue to reinforce Vyvgart and Vyvgart Hytrulo as a transformative treatment option for patients with generalized myasthenia gravis and enabled them to reduce the use of steroids.

“The results of the ADHERE trial show that Vyvgart Hytrulo reduces the risk of clinical deterioration in patients with CIDP while minimizing side effects and reducing the treatment burden,” said Jeffrey Allen, professor in the Department of Neurology at the University of Minnesota and principal investigator in the ADHERE trial. “These findings enhance our understanding of the role that IgG autoantibodies are likely to play in the disease, and open the door to new safe, effective and well-tolerated treatments that eliminate pathogenic IgGs.”

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare and serious autoimmune disease of the peripheral nervous system. People with CIDP experience fatigue, muscle weakness and a loss of feeling in their arms and legs that can get worse over time or may come and go. These symptoms can significantly impair a person’s ability to function in their daily lives. Without treatment, one-third of people living with CIDP will need a wheelchair. Although confirmation of disease pathophysiology is still emerging, there is increasing evidence that IgG antibodies play a key role in the damage to the peripheral nerves.

Generalized myasthenia gravis (gMG) is a rare and chronic autoimmune disease where IgG autoantibodies disrupt communication between nerves and muscles, causing debilitating and potentially life-threatening muscle weakness.

Vyvgart is a human IgG1 antibody fragment that binds to the neonatal Fc receptor (FcRn), resulting in the reduction of circulating IgG autoantibodies. It is the first approved FcRn blocker in the United States, European Union, China, and Canada for the treatment of adults with generalized myasthenia gravis (gMG) who are anti- acetylcholine receptor (AChR) antibody positive and in Japan for the treatment of adults with gMG who do not have sufficient response to steroids or non-steroidal immunosuppressive therapies (ISTs).

Vyvgart Hytrulo is a subcutaneous combination of Vyvgart, and recombinant human hyaluronidase PH20, Halozyme’s ENHANZE drug delivery technology to facilitate subcutaneous injection delivery of biologics. In binding to the neonatal Fc receptor (FcRn), Vyvgart Hytrulo results in the reduction of circulating IgG. It is the first-and-only approved FcRn blocker administered by subcutaneous injection.

The ADHERE study is a multicenter, randomized, double-blind, placebo-controlled trial evaluating Vyvgart Hytrulo for the treatment of 322 adult patients with CIDP. The majority of patients treated with Vyvgart Hytrulo, regardless of prior treatment, demonstrated evidence of rapid clinical improvement, and a reduced risk of relapse compared to those treated with placebo. As previously reported, ADHERE met its primary endpoint demonstrating a 61 percent reduction in the risk of relapse versus placebo. Vyvgart Hytrulo was well-tolerated, and the observed safety and tolerability profile was consistent with previous clinical trials.

In the open-label Stage A of the ADHERE study, 67 percent of patients treated with Vyvgart Hytrulo demonstrated evidence of clinical improvement (ECI), including 40 percent who had achieved ECI by the earliest possible measure at week 4. In Stage B, Vyvgart Hytrulo-treated patients maintained a clinical response to treatment longer than those on placebo as evidenced by a statistically significant and clinically relevant reduction in risk of relapse. Results across both Stage A and B indicate IgG autoantibodies play a significant role in mediating the underlying biology of CIDP.

Clinical benefit was seen across all patient subtypes, including those who had previously received corticosteroids, intravenous or subcutaneous immunoglobulin, or were on no treatment prior to study entry. Ninety nine percent of eligible patients continued to the ADHERE-Plus open-label extension study.

Argenx anticipates an FDA decision on the CIDP expanded use application by June 21, 2024, which was accepted for Priority Review in February 2024.

Argenx also presented clinical trial data and real-world evidence at the AAN meeting that continue to highlight the differentiated efficacy and safety profile of Vyvgart and Vyvgart Hytrulo in driving rapid, deep, and sustained improvement across disease scales and with different dosing schedules, including the ability for patients to achieve minimal symptom expression. Almost half of gMG patients were also able to reduce steroid use over the first six months of initiating Vyvgart treatment.

Photo: Jeffrey Allen, professor in the Department of Neurology at the University of Minnesota and principal investigator in the ADHERE trial