Safety and Efficacy of ALXN1720 in Adults With Generalized Myasthenia Gravis

A Phase 3, Randomized, Double-blind, Placebo-controlled, Parallel, Multicenter Study to Evaluate the Safety and Efficacy of ALXN1720 in Adults With Generalized Myasthenia Gravis

The purpose of this study is to evaluate the safety and efficacy of ALXN1720 for the treatment of generalized MG (gMG) in adults with autoantibodies against acetylcholine receptor (AChR).

Study Overview

• Status: Active, not recruiting
• Conditions: Generalized Myasthenia Gravis
• Intervention / Treatment: Combination product: ALXN1720; Combination product: Placebo

• Study Type: Interventional
• Enrollment (Actual): 261
• Phase: Phase 3

Contacts and Locations

Study Locations

• Argentina
  • CABA, Argentina, C1192AAW
    • Research Site
  • Ciudad de Buenos Aires, Argentina, 1181
    • Research Site
  • Ciudad de Buenos Aires, Argentina, AR-CP 1221
    • Research Site
  • Ciudad de Buenos Aires, Argentina, 1015
    • Research Site
  • Rosario, Argentina, S2000BZL
    • Research Site
• Austria
  • Innsbruck, Austria, 6020
    • Research Site
  • Wels, Austria, 4600
    • Research Site
• Brazil
  • Barretos, Brazil, 14784-400
    • Research Site
  • Joinville, Brazil, 89202-190
    • Research Site
  • Porto Alegre, Brazil, 90620-130
    • Research Site
  • Ribeirão Preto, Brazil, 14051-140
    • Research Site
  • Salvador, Brazil, 41253-190
    • Research Site
  • São José do Rio Preto, Brazil, 15090-000
    • Research Site
  • São Paulo, Brazil, 05403-010
    • Research Site
• Canada
  • Alberta
    • Edmonton, Alberta, Canada, T6G 2G3
      • Research Site
  • Ontario
    • Toronto, Ontario, Canada, M5G 2C4
      • Research Site
  • Quebec
    • Québec, Quebec, Canada, G1J 1Z4
      • Research Site
• China
  • Beijing, China, 100730
    • Research Site
  • Beijing, China, 100034
    • Research Site
  • Changchun, China, 130021
    • Research Site
  • Changsha, China, 410008
    • Research Site
  • Chengdu, China, 610041
    • Research Site
  • Fuzhou, China, 350001
    • Research Site
  • Hangzhou, China, 310003
    • Research Site
  • Hangzhou, China, 310016
    • Research Site
  • Jinan, China, 250014
    • Research Site
  • Qingdao, China, 266035
    • Research Site
  • Shanghai, China, 200040
    • Research Site
  • Suzhou, China, 215006
    • Research Site
  • Wuhan, China, 430030
    • Research Site
  • Xi'an, China, 710000
    • Research Site
• Denmark
  • Aalborg, Denmark, 9000
    • Research Site
  • Copenhagen, Denmark, 2100
    • Research Site
• France
  • Garches, France, 92380
    • Research Site
  • Lille, France, 59037
    • Research Site
  • Marseille, France, 13385
    • Research Site
  • Nice, France, 06000
    • Research Site
  • Paris, France, 75651
    • Research Site
  • Strasbourg, France, 67098
    • Research Site
• Germany
  • Berlin, Germany, 10117
    • Research Site
  • Düsseldorf, Germany, 40225
    • Research Site
  • München, Germany, 81675
    • Research Site
  • Würzburg, Germany, 97074
    • Research Site
• Israel
  • Hadera, Israel, 38100
    • Research Site
  • Haifa, Israel, 3109601
    • Research Site
  • Petah Tikva, Israel, 4910000
    • Research Site
• Italy
  • Bergamo, Italy, 24127
    • Research Site
  • Brescia, Italy, 25123
    • Research Site
  • Florence, Italy, 50139
    • Research Site
  • Milan, Italy, 20133
    • Research Site
  • Naples, Italy, 80131
    • Research Site
  • Palermo, Italy, 90127
    • Research Site
  • Pisa, Italy, 56126
    • Research Site
  • Roma, Italy, 00168
    • Research Site
  • Rome, Italy, 00189
    • Research Site
• Japan
  • Chiba, Japan, 260-8677
    • Research Site
  • Fukushima, Japan, 960-1295
    • Research Site
  • Higashimatsuyama-shi, Japan, 355-0005
    • Research Site
  • Isehara-shi, Japan, 259-1193
    • Research Site
  • Itabashi-ku, Japan, 173-8610
    • Research Site
  • Kawasaki-shi, Japan, 216-8511
    • Research Site
  • Morioka, Japan, 020-8505
    • Research Site
  • Nagasaki, Japan, 852-8501
    • Research Site
  • Nagoya, Japan, 466-0065
    • Research Site
  • Nagoya, Japan, 467-0001
    • Research Site
  • Shinjuku-ku, Japan, 160-8582
    • Research Site
  • Shinjuku-ku, Japan, 160-0023
    • Research Site
  • Suita-shi, Japan, 565-0871
    • Research Site
• Netherlands
  • Amsterdam, Netherlands, 1105 AZ
    • Research Site
• Poland
  • Bydgoszcz, Poland, 85-086
    • Research Site
  • Katowice, Poland, 40-689
    • Research Site
  • Krakow, Poland, 31-505
    • Research Site
  • Krakow, Poland, 31-202
    • Research Site
  • Lublin, Poland, 20064
    • Research Site
  • Poznan, Poland, 61-731
    • Research Site
• Portugal
  • Almada, Portugal, 2805-267
    • Research Site
  • Porto, Portugal, 4099-001
    • Research Site
• Serbia
  • Belgrade, Serbia, 11000
    • Research Site
  • Niš, Serbia, 18000
    • Research Site
• South Korea
  • Busan, South Korea, 49241
    • Research Site
  • Daegu, South Korea, 41404
    • Research Site
  • Gwangju, South Korea, 61469
    • Research Site
  • Seoul, South Korea, 02841
    • Research Site
  • Seoul, South Korea, 03722
    • Research Site
  • Seoul, South Korea, 05505
    • Research Site
  • Seoul, South Korea, 06351
    • Research Site
  • Seoul, South Korea, 5030
    • Research Site
• Spain
  • Badalona (Barcelona), Spain, 08916
    • Research Site
  • Córdoba, Spain, 14004
    • Research Site
  • L'Hospitalet de Llobregat, Spain, 08907
    • Research Site
  • Madrid, Spain, 28034
    • Research Site
  • Madrid, Spain, 28046
    • Research Site
  • Madrid, Spain, 28040
    • Research Site
  • Madrid, Spain, 28702
    • Research Site
  • Málaga, Spain, 29010
    • Research Site
  • Seville, Spain, 41009
    • Research Site
• Switzerland
  • Sankt Gallen, Switzerland, CH-9007
    • Research Site
• Taiwan
  • Kaohsiung City, Taiwan, 833401
    • Research Site
  • New Taipei City, Taiwan, 23561
    • Research Site
  • Tainan, Taiwan, 70403
    • Research Site
  • Taipei, Taiwan, 11101
    • Research Site
• Turkey (Türkiye)
  • Bursa, Turkey (Türkiye), 16059
    • Research Site
  • Istanbul, Turkey (Türkiye), 34452
    • Research Site
  • Kocaeli, Turkey (Türkiye), 41380
    • Research Site
  • Samsun, Turkey (Türkiye), 55139
    • Research Site
• United Kingdom
  • Liverpool, United Kingdom, L9 7AL
    • Research Site
  • London, United Kingdom, EC1A 7BE
    • Research Site
  • Oxford, United Kingdom, 0X3 7LE
    • Research Site
  • Sheffield, United Kingdom, S10 2JF
    • Research Site
• United States
  • California
    • Orange, California, United States, 92868
      • Research Site
  • Colorado
    • Fort Collins, Colorado, United States, 80528
      • Research Site
  • District of Columbia
    • Washington D.C., District of Columbia, United States, 20007
      • Research Site
  • Florida
    • Bradenton, Florida, United States, 34209
      • Research Site
    • Maitland, Florida, United States, 32751
      • Research Site
    • Tampa, Florida, United States, 33612
      • Research Site
  • Georgia
    • Augusta, Georgia, United States, 30912
      • Research Site
    • Gainesville, Georgia, United States, 30501
      • Research Site
    • Savannah, Georgia, United States, 31406
      • Research Site
  • Illinois
    • Springfield, Illinois, United States, 62769
      • Research Site
  • Kansas
    • Kansas City, Kansas, United States, 66160
      • Research Site
  • Kentucky
    • Lexington, Kentucky, United States, 40503
      • Research Site
  • Michigan
    • Detroit, Michigan, United States, 48202
      • Research Site
    • East Lansing, Michigan, United States, 48824
      • Research Site
  • Nevada
    • Las Vegas, Nevada, United States, 89117
      • Research Site
  • New York
    • Patchogue, New York, United States, 11772
      • Research Site
    • Rochester, New York, United States, 14620
      • Research Site
    • Syracuse, New York, United States, 13202
      • Research Site
  • North Carolina
    • Chapel Hill, North Carolina, United States, 27599
      • Research Site
  • South Carolina
    • North Charleston, South Carolina, United States, 29406
      • Research Site
  • Texas
    • Houston, Texas, United States, 77030
      • Research Site
  • Virginia
    • Richmond, Virginia, United States, 23298
      • Research Site
  • West Virginia
    • Morgantown, West Virginia, United States, 26506
      • Research Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Diagnosis of MG with generalized muscle weakness meeting the clinical criteria defined by Myasthenia Gravis Foundation of America (MGFA) Class II, III or IV
• Positive serological test for autoantibodies against AChR

Exclusion Criteria:

• History of thymectomy, or any other thymic surgery within 12 months prior to Screening
• Untreated thymic malignancy, carcinoma, or thymoma
• History of Neisseria meningitidis infection
• Pregnancy, breastfeeding, or intention to conceive during the course of the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo; Participants will receive placebo during the 26-week RCT period, after which they will enter the OLE period of the study and receive ALXN1720.	Combination product: Placebo; Combination product consisting of syringe prefilled with placebo.
Experimental: ALXN1720; Participants will receive a weight-based initial (loading) dose of ALXN1720 on Day 1, followed by weight-based maintenance treatment with ALXN1720 on Day 8 and once every week (Q1W) thereafter for a total of 26 weeks. Following this randomized controlled treatment (RCT) period, all participants will receive ALXN1720 in an open-label extension (OLE) period of 105 weeks.	Combination product: ALXN1720; Combination product consisting of syringe prefilled with ALXN1720.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Change From Baseline in Myasthenia Gravis-Activities of Daily Living (MG-ADL) Total Score at Week 26	Baseline, Week 26

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change From Baseline in Quantitative Myasthenia Gravis (QMG) Total Score at Week 26		Baseline, Week 26
Change From Baseline in Myasthenia Gravis Composite (MGC) Total Score at Week 26		Baseline, Week 26
Percentage of Responders Based on Reduction of the MG-ADL Total Score at Week 26	Response is defined as reduction of the MG-ADL total score by >= 3 points from baseline at Week 26.	Baseline up to Week 26
Percentage of Responders based on Reduction of the QMG Total Score at Week 26	Response is defined as reduction of the QMG total score by >= 5 points from baseline at Week 26	Baseline up to Week 26
Change from Baseline in the QMG total score at Week 4		Baseline, Week 4

Collaborators and Investigators

• Sponsor: Alexion Pharmaceuticals, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): November 21, 2022
• Primary Completion (Actual): May 27, 2025
• Study Completion (Estimated): August 31, 2027

Study Registration Dates

• First Submitted: September 23, 2022
• First Submitted That Met QC Criteria: September 23, 2022
• First Posted (Actual): September 27, 2022

Study Record Updates

• Last Update Posted (Actual): April 21, 2026
• Last Update Submitted That Met QC Criteria: April 14, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: MG; myasthenia gravis; gMG; generalized myasthenia gravis; acetylcholine receptor; ALXN1720; anti-acetylcholine receptor antibody-positive; AChR; complement component 5; C5; VHH antibody
• Additional Relevant MeSH Terms: Nervous System Diseases; Neoplasms by Site; Neoplasms; Neuromuscular Diseases; Autoimmune Diseases; Immune System Diseases; Autoimmune Diseases of the Nervous System; Neurodegenerative Diseases; Paraneoplastic Syndromes, Nervous System; Nervous System Neoplasms; Paraneoplastic Syndromes; Neuromuscular Junction Diseases; Myasthenia Gravis; Substandard Drugs; Pharmaceutical Preparations; Counterfeit Drugs
• Other Study ID Numbers: ALXN1720-MG-301; 2022-000460-21 (EudraCT Number)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Alexion has a public commitment to allow requests for access to study data and will be supplying a protocol, CSR, and plain language summaries.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: Yes