Efficacy, Tolerability, and Pharmacokinetics of Multiple Doses of Oral TAK-831 in Adults With Friedreich Ataxia

The purpose of this study is to evaluate the efficacy of TAK-831 versus placebo on upper extremity (arm and hands) motor function and manual dexterity. This study will also evaluate the efficacy of TAK-831 versus placebo on activities of daily living (ADL) and other secondary assessments.

The drug being tested in this study is called TAK-831. TAK-831 is being tested to treat people who have Friedreich ataxia. This study will look at upper extremity (arms and hands) motor function and manual dexterity of people who take TAK-831. Efficacy evaluations also include other neurological, functional, and patient performance assessments. The study will enroll approximately 65 participants. Participants will be randomly assigned in a 2:1:2 ratio to one of the three treatment groups-which will remain undisclosed to the participant and study doctor during the study (unless there is an urgent medical need): * TAK-831 High dose * TAK-831 Low dose * Placebo (dummy inactive pill) - this is a tablet that looks like the study drug but has no active ingredient All participants will be asked to take three tablets of high dose, low dose, or placebo twice a day for 12 weeks. This multi-center trial will be conducted in the United States. The overall time to participate in this study is approximately 13 weeks. Participants will make 5 visits to the clinic, and will be contacted by telephone for an exit interview no later than 7 days after their final visit or termination. Participants will also receive a safety follow-up phone call 7 to 17 days after receiving their last dose of TAK-831.