Interim results with SD 809 in Huntingdon's Disease-Auspex Pharma

Auspex Pharmaceuticals has announced results from a pre-specified interim subgroup analysis of the ongoing open-label ARC-HD Switch study in which the clinical experience of switching subjects' treatment from tetrabenazine to SD 809 was evaluated in patients with Huntington's disease (HD). The interim analysis was conducted to determine whether chorea control was maintained after converting subjects with HD from stable doses of tetrabenazine to SD 809, which is administered in lower doses and with a simplified dosing regimen. In accordance with the pre-specified interim analysis plan, 12 subjects were included in the subgroup analysis, all of which had chorea assessed one week after switching from tetrabenazine to SD 809 and eight of which had chorea assessed four weeks after switching (the remaining four subjects had not yet reached the four-week point in the study at the time of the pre-specified interim analysis).

At one and four weeks after switching to SD 809, the mean total chorea score decreased by approximately one point from baseline (week one change for 12 subjects was -0.83 +/-0.51 and week 4 change for eight subjects was -0.75 +/-0.75, mean and standard error), indicating that SD 809 maintained chorea control in these subjects. The conversion to SD 809 was generally well tolerated as no subject prematurely discontinued from the study, there were no adverse events of loss of chorea control and no serious adverse events were reported.