NBI-98854 for the Treatment of Tardive Dyskinesia in Subjects With Schizophrenia or Schizoaffective Disorder (KINECT Study)

This is a Phase 2, multicenter, randomized, double-blind, placebo-controlled, parallel group study to evaluate the efficacy, safety, and tolerability of two doses (50 and 100 mg) of NBI-98854 administered once daily for up to 2 weeks. The study will also allow for an evaluation of the efficacy of NBI-98854 50 mg once daily for up to 6 weeks and the safety and tolerability of NBI 98854 50 mg once daily for up to 12 weeks. The double-blind placebo-controlled treatment period the study has three arms: * NBI-98854 50 mg once daily for 6 weeks * NBI-98854 100 mg once daily for 2 weeks followed by 50 mg once daily for the remaining 4 weeks * placebo At the end of the 6-week placebo-controlled double-blind treatment period, subjects will continue in the study for an additional 6-week open-label period where all subjects who have completed the double-blind treatment period will receive NBI-98854 50 mg once daily. Two and four weeks after the last dose of study drug, follow-up assessments will be performed.