What: Following an 11.2% rally due to the release of new phase 3 data yesterday, shares in Amicus Therapeutics (NASDAQ:FOLD) climbed by another 12.05% at 1:45 p.m. EST today.

So what: Amicus Therapeutics' lead product candidate is Galafold, a therapy for the treatment of Fabry disease, a rare genetic disease characterized by the buildup of a particular type of fat in a body's cells. Fabry-disease patients face potentially life-threatening complications, including kidney damage and cardiovascular disease, and there is no cure.

Instead, Fabry disease is managed by the use of enzyme replacement therapies, including Shire's (NASDAQ: SHPG) Replagel and Sanofi's (NASDAQ:SNY) Fabrazyme, both of which provide patients with the missing or under-produced alpha-GAL enzyme responsible for the disease.

Unlike those drugs, however, Galafold helps boost alpha-GAL's effectiveness in patients who still produce at least some of the enzyme. While Galafold isn't currently approved for use in any markets, EU regulators are considering it, and a decision is expected soon. Based on the additional data reported yesterday, doctors and patients may applaud an EU green light.

In phase 3 trials, giving Galafold to patients who haven't been treated with ERTs like Replagel resulted in a statistically significant improvement in podocytes, or cells in the kidneys that build up in Fabry disease patients. Amicus Therapeutics also noted that Galafold's positive effect on kidney and cardiac function continued in a subset of patients who switched over and participated in its 19-30 month extension study.

Now what: Because Shire and Sanofi's Fabry disease drugs cost roughly $200,000 per year, and their combined annual sales eclipse $900 million, tapping into this market could be big for Amicus Therapeutics.

However, it's not a given that the EU will approve Galafold, and a setback last year resulted in the company pulling its timeline for a potential U.S. application for approval. Therefore, there's a bit of uncertainty attached to owning shares in Amicus Therapeutics.

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