Lead Program (SD-809)

SD-809 is a small molecule inhibitor of vesicular monoamine 2 transporter, or VMAT2, that is designed to regulate the levels of a specific neurotransmitter, dopamine, in the brain. A number of hyperkinetic movement disorders are triggered by abnormal dopamine regulation in the brain. We have completed a successful Phase 3 clinical trial of SD-809 for the potential treatment of chorea associated with Huntington’s disease. In this trial, which we refer to as First-HD, SD-809 met its primary efficacy endpoint of a statistically significant improvement compared to placebo in the total maximal chorea, or TMC, score on the Unified Huntington’s Disease Rating Scale over placebo, as well as showed significant improvements compared to placebo in multiple secondary endpoints including patient global impression of change, or PGIC, clinical global impression of change, or CGIC, and the physical functioning scale of the 36-Item Short-Form Health Survey developed by the RAND Corporation, or the SF-36, a measure of quality of life. Importantly, in First-HD, SD-809 showed a favorable safety and tolerability profile with low rates of adverse events, such as depression, somnolence, akathisia/restlessness and anxiety.

We have initiated two safety and efficacy clinical trials of SD-809 for the potential treatment of tardive dyskinesia. ARM-TD (Aim to Reduce Movements in Tardive Dyskinesia) is a Phase 2/3 randomized, double-blind, placebo-controlled, dose-titration clinical trial of SD-809 in approximately 90 patients with tardive dyskinesia. Topline results from this trial are expected in mid-2015. Based on feedback we obtained at a meeting with the FDA, the ARM-TD trial may qualify as one of the two pivotal trials needed for a 505(b)(2) New Drug Application, or NDA, filing, subject to FDA review. The AIM-TD (Addressing Involuntary Movements in Tardive Dyskinesia) clinical trial is a double-blind, placebo-controlled, parallel group trial in approximately 200 people with tardive dyskinesia. We expect topline results from this trial in 2016. Contingent upon successful completion of both studies, we plan to file an NDA for SD-809 for the treatment of tardive dyskinesia in 2016.

In addition to our Huntington’s disease and tardive dyskinesia programs, we have initiated an open-label preliminary efficacy, pharmacokinetic and safety Phase 1b clinical trial of SD-809 for the treatment of tics associated with Tourette syndrome. We plan to enroll approximately 20 subjects to evaluate preliminary efficacy and safety, in addition to studying the pharmacokinetics of SD-809 in adolescents. We expect topline data from this trial by mid-2015.

Deuterium-containing pirfenidone analog (SD-560)

SD-560 is currently being evaluated in a Phase 1 clinical trial. We are conducting a single-center, double-blind, randomized, two-period crossover clinical trial in healthy volunteers with equal doses of SD-560 or pirfenidone. The objectives of the clinical trial are to compare the pharmacokinetics of SD-560 and pirfenidone and their respective metabolites and to evaluate the safety and tolerability of SD-560 and inform further development activities. We expect the data from this clinical trial to be available by mid-2015.