Auspex Shares Soar on Late-Stage Results from Huntington’s Study

San Diego-based Auspex Pharmaceuticals (NASDAQ: ASPX) says it plans to file a new drug application by mid-2015 after reporting today that its lead drug candidate curbed involuntary movements associated with Huntington’s disease in a late-stage clinical trial.

The price of Auspex shares gained about 65 percent, leaping by more than $16 to $41.21 a share in after-hours trading on the Nasdaq exchange.

Auspex, which became a publicly traded company in February, specializes in replacing hydrogen atoms with deuterium to create longer-lasting versions of small-molecule drugs already approved by the FDA. In a statement released after the market closed, Auspex says a study of its experimental drug SD-809 on patients with the uncontrolled movements characteristic of Huntington’s hit the primary goal as well as multiple secondary endpoints for efficacy—and showed favorable safety and tolerability.

SD-809, the company’s lead drug candidate, is a deuterium-based analog of tetrabenazine (Xenazine), a drug the FDA approved four years ago for treating the involuntary movements, or chorea, associated with Huntington’s disease and other neural disorders. Tetrabenazine is not widely prescribed for Hungtington’s patients because it has relatively high side effects and requires frequent dosing.

Based on the data reported today, Auspex says it expects to file a new drug application by mid-2015 for treating Huntington’s chorea.

Huntington’s disease is a genetic disorder that causes a wide variety of symptoms, including involuntary movements and problems with behavior, emotion, thinking, and processing information. It eventually leads to death.

In addition to favorable safety and tolerability results, Auspex says its study showed low rates of depression, somnolence, anxiety, and restlessness for patients on SD-809.

Auspex says it also collected data on patients who switched from tetrabenazine, the current standard of care, to SD-809, which was given at about half the dose of tetrabenazine. Involuntary movements decreased in patients who received SD-809, according to Auspex, and the company says they could maintain chorea control.

Bruce V. Bigelow was the editor of Xconomy San Diego from 2008 to 2018. Read more about his life and work here. Follow @bvbigelow

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