ZIP Study Overview

Primary Study

To assess pharmacokinetic parameters of the ATB200 protein and AT2221 concentrations in plasma as well as the number of participants with adverse events, all within a time frame of 52 weeks.


Open-label, uncontrolled, multicenter study to evaluate the PK, safety, efficacy, and PD of an investigational treatment, ATB200/AT2221, in pediatric participants aged 12 to < 18 years with LOPD.


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.

What happens to the study participants after the study ends?
Participants who complete the study may have the opportunity to enroll in a separate long-term extension study.

How many participants are being enrolled in the study and how many sites are being opened for the study execution?
The estimated enrollment for the study is 14 participants and approximately 11 sites are being opened globally for the study.

What are the different steps in the study and will I need to stop taking the ERT before I enroll in the study?

  1. You will need to contact a study center/site to set up a screening appointment.
  2. Enzyme replacement therapy-experienced participants will continue to take alglucosidase alfa during the screening period; treatment with alglucosidase alfa will then be replaced by the investigational drug (AT-GAA or alglucosidase alfa/placebo) on the same schedule without interruption (i.e., every 2 weeks). The screening visit will occur over 2 days, with tests being conducted such as the 6-minute walk test (6MWT) and the pulmonary function test (PFT).
  3. Pediatric participants will be treated every other week with oral AT2221 followed by ATB200 IV. Participants will undergo PK assessments at Day 1, Week 26, and Week 52.
  4. Infusion visits will be scheduled every 2 weeks throughout the study; assessments (eg, clinical laboratory tests) for initial safety monitoring will be performed at these visits for the first 6 weeks of the study.
  5. Study visits that include efficacy, additional safety, and other assessments will be scheduled approximately every 3 months.

What is Pompe Disease?

Pompe disease is an inherited lysosomal storage disorder that results from a deficiency in acid alpha-glucosidase (GAA) and is characterized by progressive accumulation of lysosomal glycogen primarily in cardiac and skeletal muscles. Enzyme replacement therapy (ERT) using recombinant human GAA (rhGAA) is the only approved treatment available for Pompe disease.

AT-GAA is an investigational treatment paradigm that consists of a ATB200, a recombinant human acid alpha-glucosidase (rhGAA) enzyme with optimized carbohydrate structures, particularly mannose-6 phosphate (M6P), designed to enhance uptake, co-administered with AT2221, a pharmacological chaperone.