Safety and Efficacy of ALXN1720 in Adults With Generalized Myasthenia Gravis

NCT05556096 | Active Not Recruiting Phase 3 DMC FDA Drug FDA Device

• 2 other identifiers: ALXN1720-MG-3012022-000460-21
• Study Type: interventional
• Target: 261
• Locations: 22 countries
• Sites: 132

Brief Summary

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).

Conditions

Generalized Myasthenia Gravis

Keywords

ALXN1720; anti-acetylcholine receptor antibody-positive; acetylcholine receptor; AChR; generalized myasthenia gravis; myasthenia gravis; MG; gMG; complement component 5; C5; VHH antibody

Outcome Measures

Primary Outcomes (1)

• Change From Baseline in Myasthenia Gravis-Activities of Daily Living (MG-ADL) Total Score at Week 26

  Baseline, Week 26

Secondary Outcomes (5)

• Change From Baseline in Quantitative Myasthenia Gravis (QMG) Total Score at Week 26

  Baseline, Week 26

• Percentage of Responders Based on Reduction of the MG-ADL Total Score at Week 26

  Baseline up to Week 26

• Percentage of Responders based on Reduction of the QMG Total Score at Week 26

  Baseline up to Week 26

• Change From Baseline in Myasthenia Gravis Composite (MGC) Total Score at Week 26

  Baseline, Week 26

• Change from Baseline in the QMG total score at Week 4

  Baseline, Week 4

Study Arms (2)

ALXN1720

EXPERIMENTAL

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

Placebo

PLACEBO COMPARATOR

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

Interventions

ALXN1720 COMBINATION_PRODUCT

Combination product consisting of syringe prefilled with ALXN1720.

ALXN1720

Placebo COMBINATION_PRODUCT

Combination product consisting of syringe prefilled with placebo.

Placebo

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Alexion Pharmaceuticals, Inc.: lead

Study Sites (132)

Research Site

Orange, California, 92868, United States

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Fort Collins, Colorado, 80528, United States

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Washington D.C., District of Columbia, 20007, United States

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Bradenton, Florida, 34209, United States

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Maitland, Florida, 32751, United States

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Tampa, Florida, 33612, United States

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Augusta, Georgia, 30912, United States

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Gainesville, Georgia, 30501, United States

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Savannah, Georgia, 31406, United States

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Springfield, Illinois, 62769, United States

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Kansas City, Kansas, 66160, United States

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Lexington, Kentucky, 40503, United States

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Detroit, Michigan, 48202, United States

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East Lansing, Michigan, 48824, United States

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Las Vegas, Nevada, 89117, United States

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Patchogue, New York, 11772, United States

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Rochester, New York, 14620, United States

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Syracuse, New York, 13202, United States

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Chapel Hill, North Carolina, 27599, United States

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North Charleston, South Carolina, 29406, United States

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Houston, Texas, 77030, United States

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Richmond, Virginia, 23298, United States

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Morgantown, West Virginia, 26506, United States

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CABA, C1192AAW, Argentina

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Ciudad de Buenos Aires, 1015, Argentina

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Ciudad de Buenos Aires, 1181, Argentina

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Ciudad de Buenos Aires, AR-CP 1221, Argentina

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Rosario, S2000BZL, Argentina

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Innsbruck, 6020, Austria

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Wels, 4600, Austria

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Barretos, 14784-400, Brazil

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Joinville, 89202-190, Brazil

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Porto Alegre, 90620-130, Brazil

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Ribeirão Preto, 14051-140, Brazil

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Salvador, 41253-190, Brazil

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São José do Rio Preto, 15090-000, Brazil

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São Paulo, 05403-010, Brazil

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Edmonton, Alberta, T6G 2G3, Canada

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Toronto, Ontario, M5G 2C4, Canada

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Québec, Quebec, G1J 1Z4, Canada

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Beijing, 100034, China

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Beijing, 100730, China

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Changchun, 130021, China

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Changsha, 410008, China

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Chengdu, 610041, China

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Fuzhou, 350001, China

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Hangzhou, 310003, China

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Hangzhou, 310016, China

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Jinan, 250014, China

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Qingdao, 266035, China

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Shanghai, 200040, China

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Suzhou, 215006, China

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Wuhan, 430030, China

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Xi'an, 710000, China

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Aalborg, 9000, Denmark

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Copenhagen, 2100, Denmark

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Garches, 92380, France

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Lille, 59037, France

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Marseille, 13385, France

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Nice, 06000, France

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Paris, 75651, France

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Strasbourg, 67098, France

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Berlin, 10117, Germany

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Düsseldorf, 40225, Germany

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München, 81675, Germany

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Würzburg, 97074, Germany

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Hadera, 38100, Israel

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Haifa, 3109601, Israel

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Petah Tikva, 4910000, Israel

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Bergamo, 24127, Italy

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Brescia, 25123, Italy

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Florence, 50139, Italy

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Milan, 20133, Italy

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Naples, 80131, Italy

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Palermo, 90127, Italy

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Pisa, 56126, Italy

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Roma, 00168, Italy

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Rome, 00189, Italy

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Chiba, 260-8677, Japan

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Fukushima, 960-1295, Japan

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Higashimatsuyama-shi, 355-0005, Japan

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Isehara-shi, 259-1193, Japan

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Itabashi-ku, 173-8610, Japan

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Kawasaki-shi, 216-8511, Japan

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Morioka, 020-8505, Japan

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Nagasaki, 852-8501, Japan

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Nagoya, 466-0065, Japan

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Nagoya, 467-0001, Japan

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Shinjuku-ku, 160-0023, Japan

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Shinjuku-ku, 160-8582, Japan

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Suita-shi, 565-0871, Japan

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Amsterdam, 1105 AZ, Netherlands

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Bydgoszcz, 85-086, Poland

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Katowice, 40-689, Poland

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Krakow, 31-202, Poland

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Krakow, 31-505, Poland

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Lublin, 20064, Poland

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Poznan, 61-731, Poland

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Almada, 2805-267, Portugal

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Porto, 4099-001, Portugal

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Belgrade, 11000, Serbia

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Niš, 18000, Serbia

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Busan, 49241, South Korea

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Daegu, 41404, South Korea

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Gwangju, 61469, South Korea

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Seoul, 02841, South Korea

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Seoul, 03722, South Korea

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Seoul, 05505, South Korea

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Seoul, 06351, South Korea

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Seoul, 5030, South Korea

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Badalona (Barcelona), 08916, Spain

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Córdoba, 14004, Spain

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L'Hospitalet de Llobregat, 08907, Spain

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Madrid, 28034, Spain

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Madrid, 28040, Spain

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Madrid, 28046, Spain

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Madrid, 28702, Spain

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Málaga, 29010, Spain

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Seville, 41009, Spain

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Sankt Gallen, CH-9007, Switzerland

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Kaohsiung City, 833401, Taiwan

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New Taipei City, 23561, Taiwan

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Tainan, 70403, Taiwan

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Taipei, 11101, Taiwan

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Bursa, 16059, Turkey (Türkiye)

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Istanbul, 34452, Turkey (Türkiye)

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Kocaeli, 41380, Turkey (Türkiye)

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Samsun, 55139, Turkey (Türkiye)

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Liverpool, L9 7AL, United Kingdom

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London, EC1A 7BE, United Kingdom

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Oxford, 0X3 7LE, United Kingdom

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Sheffield, S10 2JF, United Kingdom

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MeSH Terms

Conditions

Myasthenia Gravis

Condition Hierarchy (Ancestors)

Paraneoplastic Syndromes, Nervous System; Nervous System Neoplasms; Neoplasms by Site; Neoplasms; Paraneoplastic Syndromes; Autoimmune Diseases of the Nervous System; Nervous System Diseases; Neurodegenerative Diseases; Neuromuscular Junction Diseases; Neuromuscular Diseases; Autoimmune Diseases; Immune System Diseases

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: This is a treatment study with 2 parallel intervention groups. The study is blinded for sponsor staff, sponsor designees, investigative site personnel, other staff directly associated with the conduct of the study, and study participants.

Study Record Dates

• First Submitted: September 23, 2022
• First Posted: September 27, 2022
• Study Start: November 21, 2022
• Primary Completion: May 27, 2025
• Study Completion (Estimated): August 31, 2027
• Last Updated: April 21, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will share

Locations

NL (1); CN (14); GB (4); DE (4); BR (7); KR (8); AR (5); JP (13); PL (6); TU (4); ES (9); SE (2); DK (2); TW (4); CA (3); PT (2); IT (9); AU (2); IL (3); US (23); FR (6); CH (1)