Generalized Myasthenia GravisPhase 3NCT05556096
Safety and Efficacy of ALXN1720 in Adults With Generalized Myasthenia Gravis
A Phase 3 study testing ALXN1720 in people with Generalized Myasthenia Gravis, run by Alexion Pharmaceuticals, Inc. at 132 sites in 22 countries.
Trial 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). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Generalized Myasthenia Gravis
- What is being tested?
- ALXN1720
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 260 participants
- Where
- 132 sitesin 22 countries
- Study dates
- 21 Nov 2022to 31 Aug 2027
- Phase
- Phase 3
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
132 sites in 22 countries.
132 sites in 22 countries
United States23 sites
Research Site
Augusta, Georgia, 30912
Research Site
Bradenton, Florida, 34209
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Chapel Hill, North Carolina, 27599
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Detroit, Michigan, 48202
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East Lansing, Michigan, 48824
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Fort Collins, Colorado, 80528
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Gainesville, Georgia, 30501
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Houston, Texas, 77030
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Kansas City, Kansas, 66160
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Las Vegas, Nevada, 89117
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Lexington, Kentucky, 40503
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Maitland, Florida, 32751
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Morgantown, West Virginia, 26506
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North Charleston, South Carolina, 29406
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Orange, California, 92868
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Patchogue, New York, 11772
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Richmond, Virginia, 23298
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Rochester, New York, 14620
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Savannah, Georgia, 31406
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Springfield, Illinois, 62769
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Syracuse, New York, 13202
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Tampa, Florida, 33612
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Washington D.C., District of Columbia, 20007
China14 sites
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Beijing, 100034
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Beijing, 100730
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Changchun, 130021
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Changsha, 410008
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Chengdu, 610041
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Fuzhou, 350001
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Hangzhou, 310003
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Hangzhou, 310016
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Jinan, 250014
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Qingdao, 266035
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Shanghai, 200040
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Suzhou, 215006
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Wuhan, 430030
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Xi'an, 710000
Japan13 sites
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Chiba, 260-8677
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Fukushima, 960-1295
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Higashimatsuyama-shi, 355-0005
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Isehara-shi, 259-1193
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Kawasaki-shi, 216-8511
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Morioka, 020-8505
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Nagasaki, 852-8501
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Nagoya, 466-0065
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Nagoya, 467-0001
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Shinjuku-ku, 160-0023
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Shinjuku-ku, 160-8582
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Suita-shi, 565-0871
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tabashi City, 173-8610
Italy9 sites
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Bergamo, 24127
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Brescia, 25123
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Florence, 50139
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Milan, 20133
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Naples, 80131
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Palermo, 90127
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Pisa, 56126
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Roma, 00168
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Rome, 00189
Spain9 sites
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Badalona (Barcelona), 08916
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Córdoba, 14004
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L'Hospitalet de Llobregat, 08907
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Madrid, 28034
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Madrid, 28040
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Madrid, 28046
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Madrid, 28702
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Málaga, 29010
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Seville, 41009
South Korea8 sites
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Busan, 49241
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Daegu, 41404
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Gwangju, 61469
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Seoul, 02841
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Seoul, 03722
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Seoul, 05505
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Seoul, 06351
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Seoul, 5030
Brazil7 sites
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Barretos, 14784-400
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Joinville, 89202-190
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Porto Alegre, 90620-130
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Ribeirão Preto, 14051-140
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Salvador, 41253-190
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São José do Rio Preto, 15090-000
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São Paulo, 05403-010
France6 sites
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Garches, 92380
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Lille, 59037
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Marseille, 13385
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Nice, 06000
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Paris, 75651
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Strasbourg, 67098
Poland6 sites
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Bydgoszcz, 85-086
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Katowice, 40-689
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Krakow, 31-202
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Krakow, 31-505
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Lublin, 20064
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Poznan, 61-731
Argentina5 sites
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CABA, C1192AAW
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Ciudad de Buenos Aires, 1015
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Ciudad de Buenos Aires, 1181
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Ciudad de Buenos Aires, AR-CP 1221
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Rosario, S2000BZL
Germany4 sites
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Berlin, 10117
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Düsseldorf, 40225
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München, 81675
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Würzburg, 97074
Taiwan4 sites
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Kaohsiung City, 833401
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New Taipei City, 23561
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Tainan, 70403
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Taipei, 11101
Turkey (Türkiye)4 sites
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Bursa, 16059
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Istanbul, 34452
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Kocaeli, 41380
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Samsun, 55139
United Kingdom4 sites
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Liverpool, L9 7AL
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London, EC1A 7BE
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Oxford, 0X3 7LE
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Sheffield, S10 2JF
Canada3 sites
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Edmonton, Alberta, T6G 2G3
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Québec, Quebec, G1J 1Z4
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Toronto, Ontario, M5G 2C4
Israel3 sites
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Hadera, 38100
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Haifa, 3109601
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Petah Tikva, 4910000
About this study
Official title: 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).
- Conditions
- Generalized Myasthenia Gravis
- Being tested
- ALXN1720, Placebo
- Keywords
- ALXN1720, anti-acetylcholine receptor antibody-positive, acetylcholine receptor, AChR, generalized myasthenia gravis, myasthenia gravis, MG, gMG, complement component 5, C5, VHH antibody
- Medical subject headings
- Myasthenia Gravis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ALXN1720Combination product
Combination product consisting of syringe prefilled with ALXN1720.
PlaceboCombination product
Combination product consisting of syringe prefilled with placebo.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: 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. Receives: Combination Product: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change From Baseline in Myasthenia Gravis-Activities of Daily Living (MG-ADL) Total Score at Week 26
Measured: Baseline, Week 26
Secondary outcomes (5)
Change From Baseline in Quantitative Myasthenia Gravis (QMG) Total Score at Week 26
Measured: 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.
Measured: 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
Measured: Baseline up to Week 26
Change From Baseline in Myasthenia Gravis Composite (MGC) Total Score at Week 26
Measured: Baseline, Week 26
Change from Baseline in the QMG total score at Week 4
Measured: Baseline, Week 4
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Sep 2022
- Study start21 Nov 2022
- Primary completion27 May 2025
- Study completion31 Aug 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Generalized Myasthenia GravisStudies of the same condition, open and under way.
- More trials run by Alexion Pharmaceuticals, Inc.The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- 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.
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 260 participants (actual)
Sponsor and investigators
- Lead sponsor
- Alexion Pharmaceuticals, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05556096
- Sponsor's protocol ID
- ALXN1720-MG-301
- Other IDs
- 2022-000460-21
- Status last verified
- Jun 2026
- First submitted
- 23 Sep 2022
- Last updated
- 17 Jun 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- Yes
- Individual data sharing
- Yes: Alexion has a public commitment to allow requests for access to study data and will be supplying a protocol, CSR, and plain language summaries.
Publications
Beltran J, Bolton S, Patel P, Sharma R. Patient engagement in protocol development for rare disease clinical trials: a framework. Res Involv Engagem. 2026 Oct 9;12(1):167. doi: 10.1186/s40900-026-00985-3.
PubMed 42855714Gwathmey KG, Sacca F, Howard JF Jr, Vu T, Xi J, Maurer M, Ruck T, Shin HY, Takahashi MP, Casasnovas C, Smilowski M, Peric S, Masuda M, Scholz J, Shang S, Yee M, Rakhade S, Annane D. Efficacy and Safety of Gefurulimab in Generalized Myasthenia Gravis: The PREVAIL Phase 3 Randomized Clinical Trial. JAMA Neurol. 2026 Jul 27:e262333. doi: 10.1001/jamaneurol.2026.2333. Online ahead of print.
PubMed 42507440
Study at a glance
From the registry record, last updated by the sponsor on 17 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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
- ClinicalTrials.gov ID
- NCT05556096
- Acronym / sponsor ID
- ALXN1720-MG-301
- Conditions
- Generalized Myasthenia Gravis
- Keywords
- ALXN1720, anti-acetylcholine receptor antibody-positive, acetylcholine receptor, AChR, generalized myasthenia gravis, myasthenia gravis, MG, gMG
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 260 participants (actual)
- Lead sponsor
- Alexion Pharmaceuticals, Inc.Industry (pharma, biotech, devices)
- Study start
- 21 Nov 2022 (actual)
- Primary completion
- 27 May 2025 (actual)
- Study completion
- 31 Aug 2027 (estimated)
- First posted
- 27 Sep 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
- Model description
- 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.
| Arm | Type | Receives |
|---|---|---|
| ALXN1720 | Experimental | Combination Product: ALXN1720Participants 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. |
| Placebo | Placebo comparator | Combination Product: PlaceboParticipants will receive placebo during the 26-week RCT period, after which they will enter the OLE period of the study and receive ALXN1720. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- 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
Key exclusion criteria (4 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ALXN1720Combination product consisting of syringe prefilled with ALXN1720. | Combination product | ALXN1720 |
| PlaceboCombination product consisting of syringe prefilled with placebo. | Combination product | Placebo |
Primary outcome
Change From Baseline in Myasthenia Gravis-Activities of Daily Living (MG-ADL) Total Score at Week 26
Time frame: Baseline, Week 26
5 secondary outcomes
Change From Baseline in Quantitative Myasthenia Gravis (QMG) Total Score at Week 26
Time frame: Baseline, Week 26
Percentage of Responders Based on Reduction of the MG-ADL Total Score at Week 26
Time frame: Baseline up to Week 26
Percentage of Responders based on Reduction of the QMG Total Score at Week 26
Time frame: Baseline up to Week 26
Change From Baseline in Myasthenia Gravis Composite (MGC) Total Score at Week 26
Time frame: Baseline, Week 26
Change from Baseline in the QMG total score at Week 4
Time frame: Baseline, Week 4
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Jun 2026.
- Derived from this study: PubMed 42855714Beltran J, Bolton S, Patel P, Sharma R. Patient engagement in protocol development for rare disease clinical trials: a framework. Res Involv Engagem. 2026 Oct 9;12(1):167. doi: 10.1186/s40900-026-00985-3.
- Derived from this study: PubMed 42507440Gwathmey KG, Sacca F, Howard JF Jr, Vu T, Xi J, Maurer M, Ruck T, Shin HY, Takahashi MP, Casasnovas C, Smilowski M, Peric S, Masuda M, Scholz J, Shang S, Yee M, Rakhade S, Annane D. Efficacy and Safety of Gefurulimab in Generalized Myasthenia Gravis: The PREVAIL Phase 3 Randomized Clinical Trial. JAMA Neurol. 2026 Jul 27:e262333. doi: 10.1001/jamaneurol.2026.2333. Online ahead of print.
- Individual participant dataSharing planned: Yes. Alexion has a public commitment to allow requests for access to study data and will be supplying a protocol, CSR, and plain language summaries.
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Generalized Myasthenia Gravis (gMG)
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
132 sites in 22 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing ALXN1720 in people with Generalized Myasthenia Gravis, run by Alexion Pharmaceuticals, Inc. at 132 sites in 22 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 17 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 132 sites in United States, China, Japan, Italy, Spain and 17 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change From Baseline in Myasthenia Gravis-Activities of Daily Living (MG-ADL) Total Score at Week 26 (time frame: Baseline, Week 26). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05556096, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Jun 2026.