Amicus Accelerates Approval Filing Plans for Rare Disease Drug

Amicus will seek accelerated approval in the U.S. for its Fabry disease therapy in the second half of the year -- sooner than many investors expected.

Author:: Adam Feuerstein
Publish date:: Mar 19, 2015 7:41 AM EDT

CRANBURY, NJ (TheStreet) -- Amicus Therapeutics (FOLD) - Get Report will seek accelerated approval in the U.S. for its Fabry disease therapy in the second half of the year -- sooner than many investors expected -- following a successful meeting with the Food and Drug Administration, the company said Thursday.

Just after the opening bell Thursday, Amicus shares roared upward by 33.4%.

A companion approval filing in Europe for the Amicus drug, known migalastat, will be submitted in the second quarter, also a bit ahead of schedule.

If approved, migalastat would be the first oral therapy for Fabry, a rare, inherited disease. As a pill, migalastat is more convenient for patients compared to Sanofi's (SNY) - Get Report Fabrazyme and Shire's (SHPG) - Get Report Replagal, both of which require bi-weekly intravenous infusions. Sales of Fabrazyme and Replagal, combined, total about $1 billion per year. Unlike its competition, migalastat only works in Fabry patients with a specific genetic mutation, estimated to encompass between 30% and 50% of Fabry patients worldwide.

The ability to seek FDA approval for migalastat this year without first needing to conduct another clinical trial removes a big overhang on the stock.

Fabry is an inherited disease affecting about 10,000 people worldwide. A genetic mutation stops an enzyme from breaking down a fatty substance known as globotriaosylceramide, or GL3. The buildup of GL3 in blood vessels throughout the body causes severe damage to kidneys, heart, brain and other organ systems. Current Fabry treatments Fabrazyme and Replagal replace the patient's misshapen or missing native enzyme and clears GL3 from the body.

Amicus' migalastat takes a different approach to treating Fabry disease. The drug is a "chaperone" which accompanies, or fixes, a patient's native enzyme. Without the Amigal chaperone, the native enzyme in a Fabry patient doesn't work well and can't get to the place in a cell where it's needed to break down GL3. But with Amigal as a helper, the native enzyme is stabilized and has increased cellular activity so it can break down GL3. Migalastat doesn't work unless enough native enzyme is present, which is why Fabry patients with too little native enzyme or badly mutated enzyme don't benefit.

Positive results from a study in which Fabry patients were able to switch to migalastat from the injectable therapies were announced last August.

In Europe, Amicus will be seeking full approval for migalstat as a new treatment for Fabry disease. Regulators there may also review the drug under an accelerated timeline.

In the U.S., Amicus will seek accelerated approval for migalastat based on biomarkers of efficacy. If approved, the company will be required to conduct a follow-on study to confirm the drug's benefit in Fabry patients. However, Amicus will be able to sell migalastat while running the confirmatory study.

Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.