Abstract Details

Title Clinical experience with efgartigimod in generalized myasthenia gravis: results from a case series of US-based patients participating in an Expanded Access Program

Topic Autoimmune Neurology

Presentation(s) P2 - Poster Session 2 (9:00 AM-3:00 PM)

Poster/Presentation
Number 011

Objective To describe the efgartigimod treatment regimens and response among 6 US-based patients with generalized myasthenia gravis (gMG) enrolled in an Expanded Access Program (EAP).

Background For some patients with gMG, available therapies do not provide sufficient symptom relief and can cause serious side effects. Efgartigimod, a human IgG1 antibody Fc-fragment (natural ligand of the neonatal crystalline fragment receptor [FcRn]), has increased affinity to FcRn vs endogenous IgG. Efgartigimod reduces IgG recycling and increases IgG degradation. Efgartigimod received FDA approval in 2021 for the treatment of gMG in adults who are anti-acetylcholine receptor (AChR) antibody positive.

Design/Methods In the efgartigimod EAP (NCT04777734), gMG patients had access to open-label efgartigimod. Eligible patients (≥18 y) met clinical criteria of the Myasthenia Gravis Foundation of America classifications II–IV and had a Myasthenia Gravis Activities of Daily Living (MG-ADL) score ≥5 points (>50% attributed to non-ocular symptoms). During the first two, fixed-treatment cycles, patients received 4 weekly infusions of efgartigimod 10 mg/kg. During the 4-week inter-treatment period, patients received their ongoing treatments and no efgartigimod infusions. Baseline demographic characteristics and safety data were collected. Treating physicians had the option to assess and track clinical function and burden of disease among treated patients.

Results As of the cutoff date (17Dec21), 8 patients have been enrolled in the US; follow-up data are available for 6 (3 males and 3 females; median age 59 y). 83% (5/6) of patients received at least 2 treatment cycles and 4–5 infusions per cycle. Symptom improvements were noted. Four patients reported 6 AEs: fatigue (resolved), tachycardia and headache (both resolved), dyspnea and diplopia (both not resolved), and back spasms (status unknown).

Conclusions We report on 6 patients with gMG who received efgartigimod as part of an EAP. Detailed patient narratives will be presented.

Authors/Disclosures
Deborah Gelinas, MD (ARGENX) PRESENTER	Dr. Gelinas has received personal compensation for serving as an employee of argenx. Dr. Gelinas has stock in argenx.
Sami L. Khella, MD, FAAN (Presbyterian Med Ctr/Dept of Neuro)	Dr. Khella has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Ionis. Dr. Khella has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Ionis. Dr. Khella has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Pfizer. Dr. Khella has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alnylam. Dr. Khella has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Eidos.
Nancy L. Kuntz, MD, FAAN (Ann & Robert H Lurie Children'S Hospital of Chicago)	Dr. Kuntz has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sarepta. Dr. Kuntz has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Argenyx. Dr. Kuntz has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Audentes Therapeutics. Dr. Kuntz has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biogen. Dr. Kuntz has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sarepta. Dr. Kuntz has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Catalyst. Dr. Kuntz has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Scholar Rock. The institution of Dr. Kuntz has received research support from Argenx. The institution of Dr. Kuntz has received research support from Astellas. The institution of Dr. Kuntz has received research support from Biogen. The institution of Dr. Kuntz has received research support from Catalyst. The institution of Dr. Kuntz has received research support from Genentech. The institution of Dr. Kuntz has received research support from Scholar Rock. The institution of Dr. Kuntz has received research support from Regenx-Bio. The institution of Dr. Kuntz has received research support from Solid Biosciences. The institution of Dr. Kuntz has received research support from AMO. The institution of Dr. Kuntz has received research support from Novartis. The institution of Dr. Kuntz has received research support from BioHaven. Dr. Kuntz has received personal compensation in the range of $50,000-$99,999 for serving as a Sarepta Express post gene therapy advisor with Sarepta.
Denis A. Ostrovskiy, MD, FAAN	Dr. Ostrovskiy has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Argenix.
	No disclosure on file
Zabeen K. Mahuwala, MD, FAAN (University of Kentucky, KY Clinic Neurology Department)	Dr. Mahuwala has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Argenx. Dr. Mahuwala has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for academic CME. Dr. Mahuwala has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Janssen Scientific affairs. Dr. Mahuwala has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for amgen. The institution of Dr. Mahuwala has received research support from UCB, . The institution of Dr. Mahuwala has received research support from Alexion . The institution of Dr. Mahuwala has received research support from argenx . The institution of Dr. Mahuwala has received research support from immunovant.

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