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AT2221

Phase 3

Pompe Disease (Late-onset) | Small molecule | Rare Disease |Amicus Therapeutics, Inc.|Last Updated: Mar 5, 2026

Success Probability

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Market & Valuation

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Trial Design

UNCONTROLLED
Total Trials1
Total Enrollment119

FDA Designations

No designations recorded

Clinical trial landscape

AT2221 · 1 trial · 1 indication

Phase 3 1
NCT04138277A Study to Assess the Long-term Safety and Efficacy of ATB200/AT2221 in Adult Subjects With Late-Onset Pompe Disease (LOPD)Pompe Disease (Late-onset)
COMPLETED119 Analytics
PHASE3COMPLETED
A Study to Assess the Long-term Safety and Efficacy of ATB200/AT2221 in Adult Subjects With Late-Onset Pompe Disease (LOPD)
Pompe Disease (Late-onset)
NCT04138277119
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Study Endpoints

Primary Endpoints

Incidence of Treatment-emergent Adverse Events (TEAEs), Treatment-emergent Serious Adverse Events (TESAEs), and TEAEs Leading to Discontinuation of Study Drug
Entire extension study (mean = 40.5 months on treatment)

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

Secondary Endpoints

Change From Baseline in 6-Minute Walk Distance (6MWD)
baseline, Week 208
Change From Baseline in Sitting % Predicted Forced Vital Capacity (FVC)
baseline, Week 208
Change From Baseline in Manual Muscle Testing (MMT) Lower Extremity Score
baseline, Week 208
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Study Design & Arms

AllocationNA
MaskingNONE
ModelSINGLE_GROUP
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
ATB200/AT2221EXPERIMENTALParticipants received ATB200 (cipaglucosidase alfa) co-administered with AT2221 capsule (miglustat)

Interventions

NameTypeDescription
AT2221DRUGParticipants received ATB200 co-administered with AT2221 (miglustat)
ATB200BIOLOGICALEnzyme Replacement Therapy via intravenous infusion
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites60

Inclusion Criteria: 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 emerge...

Countries:United StatesArgentinaAustraliaAustriaBelgiumBosnia and HerzegovinaCanadaDenmarkFranceGermanyGreeceHungaryItalyJapanNetherlandsNew ZealandPolandSloveniaSouth KoreaSpainSwedenTaiwanUnited Kingdom
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Frequently asked questions about AT2221

What is AT2221 used for in Pompe Disease?

AT2221 is an investigational small molecule being studied for the treatment of late-onset Pompe disease (LOPD), a rare genetic disorder. It is being evaluated in combination with ATB200 in adult patients. The drug is currently in Phase 3 clinical development and is not yet approved by regulatory authorities.

What does AT2221 target?

AT2221 is a small molecule designed to work alongside enzyme replacement therapy for late-onset Pompe disease. It is intended to enhance the stability and activity of the replacement enzyme, potentially improving treatment outcomes. The specific molecular target is not disclosed in the available information.

Who makes AT2221?

AT2221 is being developed by Amicus Therapeutics, Inc., a biopharmaceutical company traded on NASDAQ under the ticker symbol FOLD. The company is conducting clinical trials to evaluate the safety and efficacy of AT2221 in combination with ATB200 for the treatment of late-onset Pompe disease.

What phase is AT2221 in?

AT2221 is in Phase 3 clinical development for late-onset Pompe disease. It is an investigational drug, meaning it has not been approved by the FDA or other regulatory agencies. The Phase 3 trial has been completed, and the drug is being studied for long-term safety and efficacy in adult patients.

What clinical trials is AT2221 in?

AT2221 has been studied in one Phase 3 clinical trial, identified as NCT04138277. This trial assessed the long-term safety and efficacy of ATB200/AT2221 in adult subjects with late-onset Pompe disease. The study enrolled 119 participants across multiple countries and has been completed.

Is AT2221 the same as ATB200?

No, AT2221 is not the same as ATB200. AT2221 is a small molecule, while ATB200 is a separate investigational therapy. In clinical trials, AT2221 is administered in combination with ATB200 to evaluate their combined effect in treating late-onset Pompe disease.