Subcutaneous Efgartigimod PH20 Efficacious in Patients With CIDP Previously Treated

A new subgroup analysis of the phase 3 ADHERE trial (NCT04281472) demonstrated the efficacy of weekly 1000-mg subcutaneous (SC) efgartigimod PH20 (Vyvgart Hytrulo; Argenx) across a range of patients with chronic inflammatory demyelinating polyneuropathy (CIDP) who had treatment with a prior CIDP therapy.^1,2

Presented at the 2024 American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) meeting, held October 15-18, in Savannah, Georgia, investigators reported that the majority of participants showed confirmed evidence of clinical improvement (ECI) with efgartigimod PH20 SC, regardless of prior treatment; 77.8% (95% CI, 65.5–87.3) for those previously on corticosteroids, 58.8% (95% CI, 50.9–66.4) for those on intravenous immunoglobulin (IVIg)/SCIg, and 72.3% (95% CI, 62.2–81.1) for those off treatment. Notably, in a Kaplan-Meier analysis, results showed a similar probability of ECI over time across prior therapy subgroups.

“Vyvgart continues to deliver impactful benefits to patients in terms of safety, speed of onset, depth of response, and durability of response,” Luc Truyen, MD, PhD, chief medical officer at Argenx, said in a statement.² “The robust data we are showing at AANEM and MGFA continue to confirm Vyvgart as the leading innovative biologic with an established ability to reduce steroid usage, drive minimal symptom expression for [generalized myasthenia gravis] patients, and reduce CIDP symptoms quickly. In addition to Vyvgart, we are excited to highlight our growing neurology pipeline, including empasiprubart and ARGX-119, through which we can advance our mission of delivering transformative outcomes for even more patients.”

ADHERE was a phase 3, multistage, double-blind, placebo-controlled trial that investigated the efficacy and safety of SC efgartigimod PH20 in patients with CIDP. The efficacy of the therapy was assessed during stage A, at most 12 weeks of open-label treatment, and stage B, at most 48 weeks randomized-withdrawal, double-blind, placebo-controlled period. Authors noted that subgroups were based on prior CIDP therapy at screening and different patient/disease characteristics.

READ MORE: Phase 3b ADAPT NXT Study Confirms Efficacy of Cyclic and Biweekly Dosing of Efgartigimod in Generalized Myasthenia Gravis

The therapies previously used by patients in the analysis included corticosteroids, IVIg/SCIg, and off-treatment, meaning treatment naïve, and those who received CIDP treatment at least 6 months before study entry. For the analysis, end points included patients with confirmed ECI, time to ECI (stage A), time to first adjusted Inflammatory Neuropathy Cause and Treatment deterioration (at least 1-point score increase [relapse], stage B), and safety (stages A/B).

Presented by lead author Jeffrey Allen, MD, a professor in the department of neurology at the University of Minnesota, and colleagues, analysis of different patient/disease characteristics by subgroups revealed mostly similar rates of ECI (stage A) and hazard ratio for a decrease in the risk of relapse (stage B). Overall, in terms of safe, efgartigimod PH20 SC was well tolerated among participants, with most treatment-emergent adverse events reported as mild/moderate in severity.

In June 2024, the FDA approved Argenx's SC efgartigimod PH20 for the treatment of adults with CIDP, making it the first and only neonatal Fc receptor blocker approved for the condition.³ The therapy was approved based on data from the pivotal phase 3 ADHERE study in which treatment with the agent significantly reduced relapse risk compared with placebo. All told, patients treated with SC efgartigimod PH20 had a 61% attenuated risk relative to placebo (P = .00039), with a safety profile that was consistent with previous studies.⁴

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REFERENCES
1. Allen JA, Lewis RA, Querol L, et al. Efficacy and Safety of Subcutaneous Efgartigimod PH20 In Chronic Inflammatory Demyelinating Polyneuropathy: ADHERE Trial Subgroup Analysis. Presented at: 2024 AANEM; October 15-18; Savannah, Georgia. Abstract 176.
2. argenx Highlights Data Showing Patient Impact Across Multiple Immunology Programs at 2024 American Association of Neuromuscular & Electrodiagnostic Medicine Annual Meeting and Myasthenia Gravis Foundation of America Scientific Sessions. News Release. Argenx. Published October 15, 2024. Accessed October 18, 2024. https://argenx.com/news/2024/argenx-highlights-data-showing-patient-impact-across-multiple-im
3. argenx Announces FDA Approval of VYVGART Hytrulo for Chronic Inflammatory Demyelinating Polyneuropathy. News release. Argenx. June 21, 2024. Accessed October 18, 2024. https://www.us.argenx.com/news/argenx-announces-fda-approval-vyvgart-hytrulo-chronic-inflammatory-demyelinating-polyneuropathy
4. Argenx reports positive topline data from ADHERE study of Vyvgart Hytrulo in patients with chronic inflammatory demyelinating polyneuropathy. News release. Argenx. July 17, 2023. Accessed October 18, 2024. https://www.globenewswire.com/news-release/2023/07/17/2705309/0/en/argenx-Reports-Positive-Topline-Data-from-ADHERE-Study-of-VYVGART-Hytrulo-in-Patients-with-Chronic-Inflammatory-Demyelinating-Polyneuropathy.html