Abstract Details

Title Long-term Safety, Tolerability, and Efficacy of Efgartigimod in Patients With Generalized Myasthenia Gravis: Interim Results of the ADAPT+ Study

Topic Autoimmune Neurology

Presentation(s) S25 - Autoimmune Neurology 2: Clinical Trials and Treatment (4:06 PM-4:18 PM)

Poster/Presentation
Number 004

Background Treatment with efgartigimod, a human IgG1 antibody Fc-fragment that blocks neonatal Fc receptor, resulted in clinically meaningful improvement (CMI) in MG-specific outcome measures in the ADAPT study. All patients who completed ADAPT were eligible to enroll in its ongoing open-label, 3-year extension study, ADAPT+.

Objective Evaluate the safety, tolerability, and efficacy of efgartigimod in patients with generalized myasthenia gravis (MG) enrolled in the ADAPT+ long-term extension study.

Design/Methods Efgartigimod (EFG), 10 mg/kg, was administered intravenously in cycles of once-weekly infusions for 4 weeks, with subsequent cycles initiated based on predefined criteria. Efficacy was assessed during each cycle utilizing Myasthenia Gravis Activities of Daily Living (MG-ADL) and Quantitative Myasthenia Gravis (QMG) scales.

Results Ninety-one percent of ADAPT patients (151/167) entered ADAPT+. As of February 2021, 106 AChR-Ab+ and 33 AChR-Ab– had received at least 1 dose of open-label efgartigimod (including 66 ADAPT placebo [PBO] patients). The mean(SD) study duration was 363(114) days, resulting in 138 patient-years of observation. Similar rates of the most common adverse events (AEs) were seen in the EFG-EFG and PBO-EFG arms: headache (15.1%/30.3%), nasopharyngitis (8.2%/13.6%), and diarrhea (6.8%/10.6%). Five deaths (acute myocardial infarction, COVID-19 pneumonia/septic shock, bacterial pneumonia/MG crisis, malignant lung neoplasm, and unknown [multiple cardiovascular risk factors identified on autopsy]) occurred; none were considered related to efgartigimod by the investigator. AEs were predominantly mild or moderate. CMI was observed in AChR-Ab+ patients during each cycle (up to 10 cycles) at magnitudes comparable to improvements observed at week 3 of cycle 1 (mean[SE] improvements: MG-ADL, –5.1[0.34]; QMG, –4.7[0.41]). Clinical improvements mirrored maximal reductions in total IgG and AChR-Abs across all cycles. Similar results were observed in AChR-Ab– patients.

Conclusions This analysis suggests long-term treatment with efgartigimod was well-tolerated and efficacious, regardless of antibody status. Despite being conducted during the COVID-19 pandemic, before vaccine availability, no new safety signals were identified.

Authors/Disclosures
James F. Howard, Jr., MD, FAAN (The University of North Carolina, Dept of Neurology, CB 7025) PRESENTER	Dr. Howard has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for arenx . Dr. Howard has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Regeneron Pharmaceuticals. Dr. Howard has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alexion Pharmaceuticals. Dr. Howard has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Ra Pharma (now UCB Biosciences). Dr. Howard has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Horizon Therapeutics. Dr. Howard has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sanofi US. Dr. Howard has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis. Dr. Howard has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Academic CME. Dr. Howard has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for PeerView CME. Dr. Howard has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Platform Q CME. Dr. Howard has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Zai Laboratories. Dr. Howard has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Medscape CME. Dr. Howard has stock in General Electric dividends. Dr. Howard has stock in Johnson & Johnson dividends. Dr. Howard has stock in Pfizer dividends. An immediate family member of Dr. Howard has stock in GlaxoSmithKline dividends. An immediate family member of Dr. Howard has stock in GE Healthcare dividends. The institution of Dr. Howard has received research support from Alexion Pharmaceuticals. The institution of Dr. Howard has received research support from argenx . The institution of Dr. Howard has received research support from UCB Biosciences. The institution of Dr. Howard has received research support from NIH. The institution of Dr. Howard has received research support from Centers for Disease Control/Research Triangle Institute. The institution of Dr. Howard has received research support from Duke University (DCRI). The institution of Dr. Howard has received research support from Cartestian Therapeutics. Dr. Howard has a non-compensated relationship as a Scientific Advisiory Board member, Committee member with Myasthenia Gravis Foundation of America that is relevant to AAN interests or activities. Dr. Howard has a non-compensated relationship as a Committee member with American Assoc Neuromuscular and Electrodiagnostic Medicine that is relevant to AAN interests or activities.
Vera Bril, MD (Toronto General Hospital)	Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for UCB. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for CSL. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Alnylam. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Janssen. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Grifols. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Takeda. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Octapharma. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Pfizer. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Powell Mansfield. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Akcea. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Ionis. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Immunovant. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Sanofi. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Roche. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Momenta (now J&J). Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Alexion. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving as a Consultant for NovoNordisk. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Takeda. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Immunovant. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alexion. Dr. Bril has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Akcea. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sanofi. Dr. Bril 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. Bril has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for CSL. Dr. Bril has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Argenx. The institution of Dr. Bril has received research support from UCB. The institution of Dr. Bril has received research support from Argenx. The institution of Dr. Bril has received research support from Momenta (now J&J). The institution of Dr. Bril has received research support from Immunovant. The institution of Dr. Bril has received research support from Alexion. The institution of Dr. Bril has received research support from Takeda. The institution of Dr. Bril has received research support from Grifols. The institution of Dr. Bril has received research support from CSL. The institution of Dr. Bril has received research support from Octapharma. The institution of Dr. Bril has received research support from Akcea. The institution of Dr. Bril has received research support from Ionis. The institution of Dr. Bril has received research support from Viela Bio (now Horizon). Dr. Bril has received intellectual property interests from a discovery or technology relating to health care.
Tuan H. Vu, MD (University of South Florida)	Dr. Vu has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Dianthus. Dr. Vu has received personal compensation in the range of $500-$4,999 for serving as a Consultant for ImmunAbs. Dr. Vu has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for ARGENX. Dr. Vu has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alexion. Dr. Vu has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for UCB. Dr. Vu has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Amgen (Horizon). Dr. Vu has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Johnson & Johnson. Dr. Vu has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Alexion. Dr. Vu has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for CSL Behring. Dr. Vu has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Argenx. The institution of Dr. Vu has received research support from CSL Behring. The institution of Dr. Vu has received research support from Alexion. The institution of Dr. Vu has received research support from RA Pharma/UCB. The institution of Dr. Vu has received research support from Mass Gen Hospital/Healy Platform Study. The institution of Dr. Vu has received research support from ARGENX. The institution of Dr. Vu has received research support from Horizon/Amgen. The institution of Dr. Vu has received research support from Woolsey Pharma. The institution of Dr. Vu has received research support from CSL Behring. The institution of Dr. Vu has received research support from Cartesian Therapeutics. The institution of Dr. Vu has received research support from Janssen/Johnson & Johnson. The institution of Dr. Vu has received research support from Immunovant. The institution of Dr. Vu has received research support from Regeneron. The institution of Dr. Vu has received research support from Dianthus. The institution of Dr. Vu has received research support from COUR.
Chafic Y. Karam, MD (University of Pennsylvania)	Dr. Karam has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Alnylam. Dr. Karam has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Ionis. Dr. Karam has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Sanofi. Dr. Karam has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Argenx. Dr. Karam has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Alexion. Dr. Karam has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Neuroderm.
Stojan Peric, MD, PhD	Dr. Peric has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Argenx. Dr. Peric has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Dianthus. Dr. Peric has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Takeda. Dr. Peric has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for argenx.
Jan L. De Bleecker, MD, PhD, FAAN (Neurology/University Hospital)	Dr. De Bleecker has received personal compensation in the range of $500-$4,999 for serving as a Consultant for ArgNX. Dr. De Bleecker has received personal compensation in the range of $0-$499 for serving as a Consultant for Biogen. Dr. De Bleecker has received personal compensation in the range of $500-$4,999 for serving as a Consultant for UCB. Dr. De Bleecker has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Sanofi. Dr. De Bleecker has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Biogen. Dr. De Bleecker has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for CSL Behring. Dr. De Bleecker has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for UCB. Dr. De Bleecker has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Alnylam. Dr. De Bleecker has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Janssen pharmaceuticals.
Hiroyuki Murai, MD (International University of Health and Welfare)	Dr. Murai has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Alexion Pharmaceuticals. Dr. Murai has received personal compensation in the range of $500-$4,999 for serving as a Consultant for argenx. Dr. Murai has received personal compensation in the range of $500-$4,999 for serving as a Consultant for UCB. Dr. Murai has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Chugai Pharmaceutical. The institution of Dr. Murai has received research support from Japan Blood Products Organization.
Andreas Meisel (Charité Universitätsmedizin Berlin)	No disclosure on file
Said R. Beydoun, MD, FAAN (University of Southern California Healthcare Consultation Center 2)	Dr. Beydoun has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Alnylam. Dr. Beydoun has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Takeda. Dr. Beydoun has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Alexion. Dr. Beydoun has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Mitsubishi Tanabe. Dr. Beydoun has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Janssen. Dr. Beydoun has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for CSL. Dr. Beydoun has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Catalyst. Dr. Beydoun has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Argenx. Dr. Beydoun has received personal compensation in the range of $500-$4,999 for serving as a Consultant for UCB. Dr. Beydoun has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Octapharma. Dr. Beydoun has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Amylyx. Dr. Beydoun has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Biogen. Dr. Beydoun has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Alnylam. Dr. Beydoun has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Alexion. Dr. Beydoun has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for CSL. Dr. Beydoun has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Grifols. Dr. Beydoun has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Takeda. Dr. Beydoun has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Amylyx. Dr. Beydoun has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Argenx. The institution of Dr. Beydoun has received research support from UCB. The institution of Dr. Beydoun has received research support from Sean Healy & AMG Center for ALS. The institution of Dr. Beydoun has received research support from Alexion. The institution of Dr. Beydoun has received research support from Argenx. The institution of Dr. Beydoun has received research support from Sanofi. The institution of Dr. Beydoun has received research support from Amylyx. The institution of Dr. Beydoun has received research support from Janssen. The institution of Dr. Beydoun has received research support from Genentech. The institution of Dr. Beydoun has received research support from Regeneron.
Mamatha Pasnoor, MD, FAAN (University of Kansas Medical Center)	Dr. Pasnoor has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Argenx BVBA. Dr. Pasnoor has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Takeda Pharmaceuticals. Dr. Pasnoor has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Janssen Pharmaceutical. Dr. Pasnoor has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Immunovant. Dr. Pasnoor has received personal compensation in the range of $500-$4,999 for serving as a Consultant for UCB. Dr. Pasnoor has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for catalyst pharmaceuticals. Dr. Pasnoor has received research support from NIH.
Antonio Guglietta	Antonio Guglietta has nothing to disclose.
Peter Ulrichts	Peter Ulrichts has received personal compensation for serving as an employee of argenx. Peter Ulrichts has stock in argenx.
	No disclosure on file
Kimiaki Utsugisawa, MD, PhD (Hanamaki General Hospital)	Dr. Utsugisawa 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. Utsugisawa has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for UCB pharma. Dr. Utsugisawa has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Janssen pharma. Dr. Utsugisawa has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Viela Bio. Dr. Utsugisawa has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Chugai. Dr. Utsugisawa has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Mitsubisi Tanabe pharma. Dr. Utsugisawa has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Merck. Dr. Utsugisawa has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for argenx. Dr. Utsugisawa has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Alexion phama. Dr. Utsugisawa has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Japan Blood Products Organization. Dr. Utsugisawa has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for UCB.
Jan Verschuuren, MD, PhD (Leiden University Medical Center)	The institution of Dr. Verschuuren has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Argenx. The institution of Dr. Verschuuren has received personal compensation in the range of $0-$499 for serving as a Consultant for Rapharma. Dr. Verschuuren has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Argenx. The institution of Dr. Verschuuren has received research support from Argenx.
Renato Mantegazza, MD	Dr. Mantegazza has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alexion. Dr. Mantegazza has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for UCB. Dr. Mantegazza 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. Mantegazza has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sanofi. Dr. Mantegazza has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for SERB. The institution of Dr. Mantegazza has received research support from Alpine Immune Sciences, Inc.