An Open-label Study to Define the Safety, Tolerability and Clinical Activity of Deutetrabenazine (AUstedo) in Adult Study Subjects With DYsTonia

Study Summary

This is a single-center, open-label study of AUSTEDO in study subjects with dystonia. The study will provide preliminary experience of the safety, tolerability, and clinical activity of AUSTEDO in study subjects with dystonia. Study duration will be up to 13 weeks from screening (Visit 1) to the post treatment evaluation (Visit 5). Treatment period from drug initiation to final on-treatment Visit will be 12 weeks, or less, as follows: during the ramp-up period, study drug will start at 12 mg/day (6 mg twice daily) and will be titrated weekly by 6 mg/day increments until either 1) the maximal allowable dose (48 mg/day) is reached, or 2) dose-limiting side-effects occur. In study subjects receiving a strong CYP2D6 inhibitor, the maximum allowed dose of AUSTEDO will be 36 mg/day, reducing study duration (due to a reduction in the ramp-up period) to 11 weeks. Study subjects who experience dose-limiting side effects will be maintained on their maximum tolerated dose. Once the maximal dose is established for each participant, they will complete 6 continuous weeks on this dose (maintenance period), followed by a 1-week washout. For study subjects unable to titrate up to 48 mg/day due to side effects, the 6 weeks of maintenance will start once they reduce the study drug back to the maximum well-tolerated dose. Adverse events will be monitored throughout the study and will be reported after drug initiation. Dose reductions, suspensions, and withdrawals due to adverse events will be recorded. ECG readings will be measured at screening, during week 2, during the first week of the maintenance period (whenever this is established to be, typically week 7 for subjects able to titrate up to 48 mg/day), immediately before washout (week 12 for those study subjects who are able to titrate up to 48 mg/day) and during week 13. Assessment of Columbia Suicide Severity Rating Scale and Epworth Sleepiness Scale scores will occur at screening and all clinic Visits. The Mini Mental (MMSE) Sca

Primary Outcome

Proportion of study subjects able to titrate up to 48 mg/d (or up to 36 mg/d if receiving a strong CYP2D6 inhibitor) and able to complete the study at this dosage

Interventions

• DRUG Deutetrabenazine 6 MG