Amicus Announces Plans for Developing AT-GAA to Treat Pompe Disease

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by Alice Melao |

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AT-GAA trial, FDA

Amicus Therapeutics is planning to launch a pivotal trial to compare its investigational therapy AT-GAA (ATB200/AT221) to the current standard of care available for patients with Pompe disease.

The new trial is expected to provide additional clinical data to support Accelerated Approval for AT-GAA by the U.S. Food and Drug Administration. Amicus expects to submit the package in 2019.

The study was designed based on input given by the FDA during a Type C meeting held this summer, along with prior scientific advice received from the European Medicines Agency (EMA).

This study is expected to start this year, and Amicus plans to enroll about 100 patients, regardless of whether they’ve received prior treatment with enzyme replacement therapy (ERT).

Patients who participated in the ongoing STRIDE observational study (NCT03347253) are also eligible to participate in this new trial.

During the trial, the researchers will evaluate and compare the potential of AT-GAA with standard of care to sustain or improve the patient’s physical capacity, as determined by the six-minute walk test, over a period of 12 months.

“We look forward to initiating the Pompe pivotal trial this year following collaborative discussions with regulators in the U.S. and the E.U.,” John F. Crowley, chairman and CEO of Amicus Therapeutics, said in a press release.

“We continue to take steps forward in this vitally important program and will significantly enhance the body of clinical data for AT-GAA through the upcoming pivotal study as well as through ongoing clinical studies over the coming months,” he added.

As result of the regulatory meeting, the FDA noted that the clinical data available on AT-GAA is not currently sufficient to support full approval. In addition to the pivotal new trial, Amicus aims to initiate studies in additional patient groups, including pediatric Pompe patients, in 2019.

Meanwhile, the company will continue its ongoing clinical studies.

It expects to complete its STRIDE natural history study in about 125 ERT-treated Pompe patients later this year.

Amicus is also planning to present long-term data on 19 patients treated with AT-GAA in the ongoing Phase 1/2 trial (NCT02675465), as well as data collected from 10 additional patients included in the new Cohort 4 arm of the study.

The latest results of the Phase 1/2 trial will be presented at the upcoming World Muscle Society Congress 2018, Oct. 2-6 in Mendoza, Argentina.

“Our commitment remains the same as it has always been since we initiated the development of our Pompe cell line — to deliver this potential new therapy to as many people living with Pompe disease as soon as possible,” Crowley said.

AT-GAA is a combination therapy that consists of a man-made optimized acid alpha-glucosidase (GAA) enzyme — which is faulty in Pompe disease — co-administered with a small molecule that works as a pharmacological chaperone.

Initial results of the Phase 1/2 trial collected from the first 20 treated patients demonstrated that AT-GAA could significantly increase the mean levels and activity of GAA enzyme. Also, the stability of the enzyme increased about 28.6% in the presence of the small molecule chaperone.

The data revealed that the treatment could prevent muscle deterioration and halt the accumulation of hexose tetrasaccharide (Hex4), a well-known biomarker of the disease.