After phase 3 fumble and failed SPAC, Amicus' Pompe disease drug hits another delay to approval

As if a phase 3 failure followed by a SPAC merger crashing and burning wasn’t enough for Amicus Therapeutics, the company’s late-phase therapy for Pompe disease has faced another setback in the form of a delayed FDA review.

The regulator has extended its review period for the two components of its AT-GAA therapy by 90 days. It means that the biologics license application for the recombinant human acid alpha-glucosidase cipaglucosidase alfa won’t be decided until August 29, while a verdict on the new drug application for the other component, an enzyme stabilizer called miglustat, won’t be reached until October 29.

It’s not the first bump in the road for AT-GAA, which missed its primary endpoint in a phase 3 study in late-onset Pompe disease in February 2021. A year later, Amicus blamed “market conditions” for the failure of its SPAC merger to take off.

With the end of the SPAC dream, Amicus said at the time that it planned to prioritize its gene therapy pipeline as part of a push to generate $400 million in net savings through 2026.

There is a still a chance to get things back on track. Responding to the FDA’s latest update, Amicus expressed confidence Tuesday that despite the extended review period for both components of AT-GAA, the regulator would still approve the applications together. The extensions were not related to requests for any additional clinical data, the company pointed out.

“We continue to work collaboratively with the FDA as it completes its review of the AT-GAA applications,” said John Crowley, Chairman and CEO at Amicus Therapeutics. “We remain deeply committed to bringing AT-GAA to as many people living with Pompe disease as quickly as possible and delivering on our promise to become the potential new standard of care.”

Pompe disease is an inherited lysosomal disorder caused by deficiency of the enzyme acid alpha-glucosidase. It affects between 5,000 and 10,000 people worldwide, who suffer from severe muscle weakness that worsens over time.

Editor's note: This article was amended on May 12, 2022, to clarify that the phase 3 AT-GAA readout was in February 2021.