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Pompe Disease (Late-onset)Phase 3NCT04138277

A Study to Assess the Long-term Safety and Efficacy of ATB200/AT2221 in Adult Subjects With Late-Onset Pompe Disease (LOPD)

A Phase 3 study testing AT2221 and ATB200 in people with Pompe Disease (Late-onset), run by Amicus Therapeutics at 60 sites in 23 countries.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
Search all trials

Trial summary

This is a multicenter, international open-label extension study of ATB200/AT2221 in adult subjects with late-onset Pompe disease (LOPD) who completed Study ATB200-03. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Pompe Disease (Late-onset)
What is being tested?
AT2221 and ATB200
Could I receive a placebo?
No, everyone receives an active treatment
How many people
119 participants
Where
60 sitesin 23 countries
Study dates
18 Dec 2019to 31 Dec 2024
Phase
Phase 3
Are there results?
Yes, posted in the registrySummary in the doctors' view

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

  • 1. Subject must have completed Study ATB200-03.
  • Note: Subjects who were forced to withdraw from Study ATB200-03 for a logistical reason not related to the efficacy or safety of cipaglucosidase alfa/miglustat (eg, hospitalization for a car accident, COVID-19 pandemic, or emergency surgery) that resulted in several consecutive missed doses may have been eligible to participate in this study upon approval by the Amicus medical monitor.

Who cannot join

  • Subject plans to receive gene therapy or participate in another interventional study for Pompe disease.
  • Subject, if female, is pregnant or breastfeeding.
  • Subject, whether male or female, is planning to conceive a child during the study.
  • Subject had a hypersensitivity to any of the excipients in cipaglucosidase alfa or miglustat, or had a medical condition or any other extenuating circumstance that may have, in the opinion of the investigator or medical monitor, posed an undue safety risk to the subject or may have compromised his/her ability to comply with or adversely impacted protocol requirements.

Trial locations and contacts

60 sites in 23 countries.

60 sites in 23 countries

United States18 sites
  • Emory Clinic

    Atlanta, Georgia, 30322

  • Billings Clinic

    Billings, Montana, 59101

  • University of Cincinnati Gardner Neuroscience Institute

    Cincinnati, Ohio, 45219

  • Cincinnati Children's Hospital

    Cincinnati, Ohio, 45229

  • The Ohio State University Wexner Medical Center

    Columbus, Ohio, 43210

  • Duke University Medical Center

    Durham, North Carolina, 27710

  • Lysosomal and Rare Disorders Research and Treatment Center, Inc.

    Fairfax, Virginia, 22030

  • University of Florida Clinical Research Center

    Gainesville, Florida, 32610

  • Northwell Health

    Great Neck, New York, 11021

  • Hackensack University Medical Center

    Hackensack, New Jersey, 07061

  • IU Health Neuroscience Center

    Indianapolis, Indiana, 46202

  • University of California, Irvine

    Irvine, California, 92868

  • University of Arkansas for Medical Sciences

    Little Rock, Arkansas, 72205

  • NYU School of Medicine

    New York, New York, 10017

  • University of Pennsylvania

    Philadelphia, Pennsylvania, 19104

  • UPMC Montefiore Clinical and Translational Research Center

    Pittsburgh, Pennsylvania, 15213

  • University of Utah

    Salt Lake City, Utah, 84108

  • Washington University School of Medicine

    St Louis, Missouri, 63110

Other trials in United States

France5 sites
  • Hôpital Pierre Wertheimer

    Bron, 69577

  • Hôpital Raymond Poincaré

    Garches, 92380

  • Hôpital Salengro

    Lille, 59037

  • Hôpital de la Timone

    Marseille, 13385

  • Hôpital Pasteur 2

    Nice, 06001

Other trials in France

Japan5 sites
  • Fukuoka University Hospital

    Fukuoka, 814-0180

  • Kagoshima University Hospital

    Kagashima, 890-8520

  • Izumi City General Hospital

    Osaka, 594 0073

  • Hokkaido University Hospital

    Sapporo, 060 8648

  • The Jikei University Hospital

    Tokyo, 105-8471

Other trials in Japan

Australia4 sites
  • Royal Adelaide Hospital

    Adelaide, South Australia, 5000

  • Royal Brisbane & Women's Hospital

    Brisbane, Queensland, 4029

  • Monash Medical Centre

    Clayton, Victoria, 3168

  • Westmead Hospital

    Westmead, New South Wales

Other trials in Australia

United Kingdom4 sites
  • Queen Elizabeth Hospital Birmingham

    Birmingham, B15 2TH

  • Cambridge University Hospitals NHS Foundation Trust

    Cambridge, CB2 0QQ

  • Royal Free Hospital NHS Foundation Trust

    London, NW3 2QG

  • Salford Royal NHS Foundation Trust

    Salford, M6 8HD

Other trials in United Kingdom

Germany3 sites
  • Universitätsklinikum Bonn

    Bonn, 53127

  • Friedrich-Baur Institut

    München, 80336

  • Universitätsklinikum Münster

    Münster, 48149

Other trials in Germany

Hungary3 sites
  • Semmelweis University

    Budapest, 1085

  • University of Pécs

    Pécs, 7623

  • University of Szeged

    Szeged, 6725

Other trials in Hungary

Canada2 sites
  • Alberta Children's Hospital, Heritage Medical Research Clinic

    Calgary, Alberta, T3B 6A8

  • McMaster University Medical Centre

    Hamilton, Ontario, L8N 3Z5

Other trials in Canada

Italy2 sites
  • UOC di Neurologia e Malattie Neuromuscolari

    Messina, 98124

  • Universitaria Federico II

    Naples, 80131

Other trials in Italy

Argentina1 site
  • Hospital Universitario Austral

    Buenos Aires, B1629ODT

Other trials in Argentina

Austria1 site
  • Medizinische Universität Innsbruck

    Innsbruck, A-6020

Other trials in Austria

Belgium1 site
  • UZ Leuven

    Leuven, 3000

Other trials in Belgium

Bosnia and Herzegovina1 site
  • University Clinical Centre of the Republic of Srpska

    Banja Luka, The Republic of Srpska, 78000

Other trials in Bosnia and Herzegovina

Denmark1 site
  • Aarhus Universitetshospital

    Aarhus

Other trials in Denmark

Greece1 site
  • Eginition Hospital

    Athens, 11528

Other trials in Greece

Netherlands1 site
  • Erasmus MC

    Rotterdam, 3015 GD

Other trials in Netherlands

New Zealand1 site
  • University of Auckland

    Auckland, 1142

Other trials in New Zealand

Poland1 site
  • Centrum Medyczne Medyk

    Rzeszów, Podkarpackie Voivodeship, 35-326

Other trials in Poland

Slovenia1 site
  • University Medical Centre Ljubljana

    Ljubljana, 1000

Other trials in Slovenia

South Korea1 site
  • Pusan National University

    Yangsan, Gyeongsangnam-do, 50612

Other trials in South Korea

Spain1 site
  • Hospital de la Santa Creu I Sant Pau

    Barcelona

Other trials in Spain

Sweden1 site
  • Sahlgrenska University Hospital

    Gothenburg, 41345

Other trials in Sweden

Taiwan1 site
  • National Taiwan University Hospital

    Taipei, 100

Other trials in Taiwan

About this study

Official title: A Phase 3 Open-label Extension Study to Assess the Long-term Safety and Efficacy of Intravenous ATB200 Co-administered With Oral AT2221 in Adult Subjects With Late-onset Pompe Disease (LOPD)

This is a multicenter, international open-label extension study of ATB200/AT2221 in adult subjects with late-onset Pompe disease (LOPD) who completed Study ATB200-03.

Read the detailed description

This is an open-label extension study for subjects who completed the ATB200-03 study. The subjects will stay in this study until regulatory approval or marketing authorization and/or commercialization in the participating subject's country.

Being tested
AT2221, ATB200
Keywords
Pompe, rhGAA
Medical subject headings
Glycogen Storage Disease Type II

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • AT2221Drug

    Also called miglustat

    Participants received ATB200 co-administered with AT2221 (miglustat)

  • ATB200Biological

    Also called cipaglucosidase alfa

    Enzyme Replacement Therapy via intravenous infusion

Study groups in NCT04138277
Study groupRoleWhat they receive
ATB200/AT2221ExperimentalParticipants received ATB200 (cipaglucosidase alfa) co-administered with AT2221 capsule (miglustat)
Receives: Drug: AT2221; Biological: ATB200

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Incidence of Treatment-emergent Adverse Events (TEAEs), Treatment-emergent Serious Adverse Events (TESAEs), and TEAEs Leading to Discontinuation of Study Drug

    Number of subjects with TEAE, TESAE, and TEAE leading to discontinuation during this long-term extension study

    Measured: Entire extension study (mean = 40.5 months on treatment)

Secondary outcomes (12)
  1. Change From Baseline in 6-Minute Walk Distance (6MWD)

    Motor function was measured using the 6-minute walk distance (meters)

    Measured: baseline, Week 208

  2. Change From Baseline in Sitting % Predicted Forced Vital Capacity (FVC)

    Pulmonary function was measured by sitting % predicted forced vital capacity (FVC)

    Measured: baseline, Week 208

  3. Change From Baseline in Manual Muscle Testing (MMT) Lower Extremity Score

    Strength was measured by manual muscle testing (MMT) using the Medical Research Council grading scale (0 to 5 points, with 5 indicating normal function). Change from baseline values >0 represent improvement.

    Measured: baseline, Week 208

  4. Change From Baseline in the Total Score for Patient-reported Outcomes Measurement Information System (PROMIS®) - Physical Function

    Physical Function Short Form 20a (v2.0) consisted of 20 questions. The first 14 questions were each scored on a scale from 1 to 5 as follows: 1 = unable to do; 2 = with much difficulty; 3 = with some difficulty; 4 = with a little difficulty; 5 = without any difficulty; the next 6 questions were each scored on a scale from 1 to 5 as follows: 1 = cannot do; 2 = quite a lot; 3 = somewhat; 4 = very little; 5 = not at all. The total score was calculated by summing up scores (1 to 5) across all items. Total scores range from 20 to 100. A higher score represented a better outcome.

    Measured: baseline, Week 208

  5. Change From Baseline in the Total Score for PROMIS® - Fatigue

    Fatigue Short Form 8a consisted of 6 questions, each scored on a scale from 1 to 5 as follows: 1 = not at all; 2 = a little bit; 3 = somewhat; 4 = quite a bit; 5 = very much; and 2 questions, each scored on a scale from 1 to 5 as follows: 1 = never; 2 = rarely; 3 = sometimes; 4 = often; 5 = always. The total score was calculated by summing up scores (1 to 5) across all items resulting in a total score range from 6 (minimum) to 30 (maximum). A lower score represented lower fatigue symptoms.

    Measured: baseline, Week 208

  6. Change From Baseline in Gait, Stairs, Gower, Chair (GSGC) Test

    The GSGC consisted of a 10-meter walk for evaluation of gait, a 4-stair climb, Gowers' maneuver, and arising from a chair. Results of the GSGC included the time required to complete the individual tests, individual scores for each of the tests (1 to 7 points for each of gait, 4-stair climb, and Gowers' maneuver, and 1 to 6 points for arising from a chair), and a total score. GSGC total score was the sum of the component scores from the 4 functional tests. The total score ranged from a minimum of 4 points (normal performance) to a maximum of 27 points (worst performance).

    Measured: baseline, Week 208

  7. Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses

    The EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) questionnaire comprises 5 dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Each dimension has 5 levels: Level 1=no problems, Level 2=slight problems, Level 3=moderate problems, Level 4=severe problems, and Level 5=extreme problems. In this categorical assessment, subjects were asked to indicate their health state by ticking the box next to the most appropriate statement in each of the 5 dimensions.

    Outcomes for change from baseline at Week 208 include 'no change', 'worsening' relative to baseline category, or 'improvement' relative to baseline category. Changes (worsening or improvement) are shown by magnitude of change (how many Levels) in each categorical assessment.

    Measured: baseline, Week 208

  8. Change From Baseline in Overall Physical Well-being (Subject's Global Impression of Change [SGIC], Question 1)

    The Subject's Global Impression of Change overall physical well-being (question 1) is scored on a 7-point rating scale ranging from "very much worse" to "very much improved."

    Measured: baseline, Week 208

  9. Change From Baseline in Physician's Global Impression of Change (PGIC) Overall Status

    The Physician's Global Impression of Change (PGIC) is designed to record the physician's assessment of the subject's status, taking into account the subject's signs and symptoms and other neuromuscular symptoms, and signs relative to their status at the Baseline Visit. The PGIC is based on a single item that is scored on a 7-point rating scale ranging from 1 "very much worse" to 7 "very much improved."

    Measured: baseline, Week 208

  10. Percent Change From Baseline in Creatine Kinase (U/L)

    Percent change from baseline to Week 208 in the levels of biomarker creatine kinase (CK)

    Measured: baseline, Week 208

  11. Percent Change From Baseline in Urine Hex4 (mmol/Mol Creatinine)

    Percent change from baseline to Week 208 in the levels of biomarker urine Hex4.

    Measured: baseline, Week 208

  12. Proportion of Subjects With Positive Anti-drug Antibodies at Baseline and Week 208

    Immunogenicity was assessed by the number (%) of subjects with positive specific anti-cipaglucosidase antibodies at baseline and at Week 208

    Measured: baseline, Week 208

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted24 Oct 2019
  2. Study start18 Dec 2019
  3. Primary completion31 Dec 2024
  4. Study completion31 Dec 2024

Resources

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
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
119 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04138277
Sponsor's protocol ID
ATB200-07
Status last verified
Mar 2026
First submitted
18 Oct 2019
Last updated
5 Mar 2026
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Publications

  • Hopkin RJ, Byrne BJ, Dimachkie MM, Kishnani PS, Mozaffar T, Roberts M, Schoser B, van der Beek NAME, van der Ploeg AT, Wenninger S, Brudvig J, Fox B, Holdbrook F, Jain V, Johnson F, Zhang J, Parenti G. Miglustat: a first-in-class enzyme stabilizer for cipaglucosidase alfa for the treatment of late-onset Pompe disease. Ther Adv Rare Dis. 2026 Feb 26;7:26330040261425686. doi: 10.1177/26330040261425686. eCollection 2026 Jan-Dec.

    PubMed 41769220
  • Andersen H, Diaz-Manera J, Goker-Alpan O, Mozaffar T, Sitaraman Das S, Fox B, Amon F, O'Brien-Prince K, Goldman M, Holdbrook F, Jain V, Byrne BJ. Safety of home administration of cipaglucosidase alfa plus miglustat in late-onset Pompe disease: results from multiple clinical trials. Ther Adv Rare Dis. 2026 Jan 31;7:26330040261416943. doi: 10.1177/26330040261416943. eCollection 2026 Jan-Dec.

    PubMed 41631150
  • Schoser B, Kishnani PS, Bratkovic D, Byrne BJ, Claeys KG, Diaz-Manera J, Laforet P, Roberts M, Toscano A, van der Ploeg AT, Castelli J, Goldman M, Holdbrook F, Sitaraman Das S, Wasfi Y, Mozaffar T; ATB200-07 Study Group. 104-week efficacy and safety of cipaglucosidase alfa plus miglustat in adults with late-onset Pompe disease: a phase III open-label extension study (ATB200-07). J Neurol. 2024 May;271(5):2810-2823. doi: 10.1007/s00415-024-12236-0. Epub 2024 Feb 28.

    PubMed 38418563

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing AT2221 and ATB200 in people with Pompe Disease (Late-onset), run by Amicus Therapeutics at 60 sites in 23 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: finished, as of the sponsor's last update on 5 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 60 sites in United States, France, Japan, Australia, United Kingdom and 18 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. 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?

Yes. Results are posted in the registry (first posted 12 Jan 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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?

Incidence of Treatment-emergent Adverse Events (TEAEs), Treatment-emergent Serious Adverse Events (TESAEs), and TEAEs Leading to Discontinuation of Study Drug (time frame: Entire extension study (mean = 40.5 months on treatment)). 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 NCT04138277, which also lists 3 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 5 Mar 2026; AzTrials last refreshed its copy on 2 Nov 2026.

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