Handok's Vyvgart Approved for Generalized Myasthenia Gravis Treatment
The Ministry of Food and Drug Safety (MFDS) in South Korea has granted approval to Handok's Vyvgart (efgartigimod alfa) for the treatment of adult patients with generalized myasthenia gravis (gMG) who are anti-acetylcholine receptor (AChR) antibody positive. This approval introduces a novel mechanism targeting the neonatal Fc receptor (FcRn) to degrade pathogenic autoantibodies, marking a significant advancement in the treatment of gMG.
Clinical Trial Results
The safety and efficacy of Vyvgart were evaluated in a 26-week, multi-center, randomized, double-blind, placebo-controlled clinical trial. The trial's primary efficacy endpoint was the Myasthenia Gravis-Activities of Daily Living (MG-ADL) score, which assesses the impact of gMG on daily activities. Participants treated with Vyvgart showed a statistically significant reduction in MG-ADL scores compared to those receiving a placebo.
- MG-ADL Scores: The median MG-ADL total score was 9 in both the Vyvgart and placebo groups.
- QMG Scores: The median Quantitative Myasthenia Gravis (QMG) total score was 17 in the Vyvgart group and 16 in the placebo group.
Participants received up to three treatment cycles based on their body weight, with the primary efficacy outcome comparing the proportion of MG-ADL responders in the AChR-Ab positive population during the first treatment cycle (C1). An MG-ADL responder was defined as a patient who experienced a reduction of at least 2 points from baseline for a minimum of four consecutive weeks.
Secondary Efficacy Endpoint
The key secondary efficacy endpoint assessed QMG response rates in the AChR-Ab positive population during the C1 period. QMG scores, ranging from 0 to 39, evaluate muscle weakness severity, with higher scores indicating greater impairment. QMG responders demonstrated a reduction of at least 3 points from baseline for a minimum of four consecutive weeks.
Vyvgart achieved statistically significant improvements in both MG-ADL and QMG responder rates compared to the placebo group during the first treatment cycle.
Regulatory Fast Track
The MFDS had previously designated Vyvgart as the 22nd product under the 'Global Innovative Fast Track (GIFT)' program in November 2023, expediting the approval process. This designation underscores the ministry's commitment to leveraging regulatory science expertise to ensure rapid availability of new treatments for rare diseases.
"We are committed to utilizing regulatory science expertise to ensure that new treatments for rare diseases are rapidly supplied to patients, expanding treatment opportunities," the ministry stated.
This approval not only represents a significant milestone for Handok and Argenx but also offers new hope for patients suffering from gMG, providing them with an effective adjunct therapy to manage their condition.
