for people ages 12-17 (full criteria)
at Oakland, California and other locations
study started
estimated completion



This is a Phase 3, open-label, uncontrolled, multicenter study to evaluate the PK, safety, efficacy, and PD of ATB200/AT2221 treatment in pediatric subjects aged 12 to < 18 years with LOPD. Enzyme replacement therapy (ERT)-experienced subjects are those who have received at least 1 dose of alglucosidase alfa prior to enrolling in this study.

Official Title

An Open-label Study of the Pharmacokinetics, Safety, Efficacy, and Pharmacodynamics of ATB200/AT2221 in Pediatric Subjects Aged 12 to < 18 Years With Late-onset Pompe Disease


The study will consist of a 30-day screening period, a 12-month treatment period, and a 30-day safety follow-up period, for a total duration of approximately 14 months. Subjects who complete this study may have an opportunity to enroll in a separate long-term extension study. Pediatric subjects will be treated every other week with oral AT2221 followed by ATB200 IV. Subjects will undergo PK assessments at Day 1, Week 26, and Week 52. Safety assessments include monitoring of adverse events, clinical laboratory tests, physical examinations, vital signs, echocardiograms, 12-lead electrocardiogram (ECG), and detection of ATB200 antibodies. Efficacy assessments include evaluation of ambulatory function (6-Minute Walk Test [6MWT]); motor function tests; muscle strength; pulmonary function tests; Patient-reported Outcomes Measurement Information System (PROMIS®) for dyspnea, fatigue, physical functioning, and upper extremity; Gross Motor Function Measure-88 Items (GMFM-88); Pompe-pediatric Evaluation of Disability Inventory (PompePedi); Subject/Physician Global Impression of Change (SGIC/PGIC); Visual Analog Scale (VAS) for pain assessment, and time to initiation of use of assistive device. The patient-reported outcomes are to be completed if available. Pharmacodynamic (PD) assessments include measurement of serum creatine kinase (CK) levels and urinary hexose tetrasaccharide (Hex4) levels.


Pompe Disease (Late-onset) Pompe rhGAA Glycogen Storage Disease Type II Miglustat ATB200 ATB200/AT2221


You can join if…

Open to people ages 12-17

  1. Male or female subjects (ERT-naïve or ERT-experienced), diagnosed with late-onset Pompe disease who are aged 12 to < 18 years at screening
  2. Subject weighs ≥ 25 kg and ≤ 115 kg
  3. Subject's parent or legally authorized representative is willing and able to provide written informed consent and authorization for use and disclosure of personal health information or research-related health information, and subject provides assent, if applicable based on site and local regulations
  4. Subject must have a diagnosis of LOPD
  5. Subject has a sitting FVC ≥ 30% of the predicted value for healthy adolescents (Global Lung Function Initiative [GLI]) at screening
  6. Subject performs two 6MWTs at screening that are valid, as determined by the clinical evaluator, and that meet all of the following criteria:
  7. both screening values of 6-Minute Walk Distance (6MWD) are ≥ 75 meters
  8. the lower value of 6MWD is within 20% of the higher value of 6MWD

You CAN'T join if...

  1. Subject has received any investigational/experimental drug, biologic or device within 30 days or 5 half-lives of the therapy or treatment, whichever is longer, before screening
  2. Subject has received any gene therapy at any time
  3. Female subject is pregnant or breast-feeding at screening
  4. Subject requires the use of ventilation support for > 6 hours per day while awake


  • UCSF Benioff Children's Hospital accepting new patients
    Oakland California 94609 United States
  • Neuromuscular Research Center accepting new patients
    Phoenix Arizona 85028 United States


accepting new patients
Start Date
Completion Date
Amicus Therapeutics
Phase 3
Study Type
Last Updated