Auspex Pharmaceuticals Plans Phase III Clinical Trial for Chorea in HD Patients

Posted on February 27, 2015

Auspex Pharmaceuticals is a small biotechnology company based in La Jolla, CA. Auspex’s tunique approach to developing therapeutics is to incorporate deuterium (a non-radioactive, non-toxic, naturally occurring form of hydrogen) into the molecular structure of existing FDA approved drugs.

The rationale and hope for this is that the substitution of deuterium for hydrogen at specific locations on a drug will reduce the drug’s rate of metabolism, or breakdown, by enzymes in the liver. Decreased metabolism could increase the length of time a dosage has an effect without changing the drug’s mechanism of action. As a result, lower doses and less frequent dosing, possibly leading to improved safety and convenience than the original drug formula.

Auspex’s lead compound, SD-809, is a deuterium-substituted analogue of tetrabenazine (Xenazine), the only drug currently approved in the United States for the treatment of Huntington’s chorea. Both tetrabenazine and SD-809 work by inhibiting the vesicular monoamine transporter 2 (VMAT2). VMAT2 is responsible for priming small synaptic vesicles with the neurotransmitters, dopamine and serotonin so that they can be released into the synapse as needed by the body. Treatment with a VMAT2 inhibitor will prevent these neurotransmitters from being packaged and result in decreased synaptic dopamine levels. Lowering the levels of synaptic dopamine is thought to improve the chorea commonly associated with HD.

SD-809 is expected to enter Phase III clinical testing in April 2013 to determine whether is effective in the treatment of chorea. Auspex hope plans to recruit 90 participants in all, across 30 different research sites across the US and Canada. 45 people are expected to receive SD-809 and 45 are to serve as placebo controls.

For more information on this trial visit Clinical website at: and check back on the HDSA website research section for news and listings of trial sites as they come online. To receive email notices for this upcoming trial, or any HD clinical study or trial, please register at

Posted in Our opinion, Uncategorized, Weekly News
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