Efficacy and Safety Study of Adjunctive Troriluzule in Obsessive Compulsive Disorder

Key Inclusion Criteria:

1. Primary diagnosis of obsessive-compulsive disorder (OCD) as per Diagnostic andStatistical Manual of Mental Disorders, Fifth Edition as confirmed by the MINI atscreening; the duration of the subjects illness must be ≥ 1year

2. An inadequate response to current Standard of Care medication defined as selectiveserotonin reuptake inhibitor (excluding fluvoxamine) or clomipramine treatment at anadequate and stable dose for at least 8 weeks prior to screening and at least 12weeks at baseline (adequate dose defined by USPI labeling); an inadequate responsetoo current standard of car base on the YBOCS score.

3. Determined by the investigator to be medically stable at baseline/ randomization asassessed by medical history, physical examination, laboratory test results, andelectrocardiogram testing. Subjects must be physically able and expected to completethe trail as designed.

Key Exclusion Criteria:

1. Subjects with a history of more than two (2) previous failed or inadequate treatmentclasses given for an adequate duration at an adequate dose as defined by theMGH-TRQ-OCD.

2. Current or prior history of: bipolar I or II disorder, schizophrenia or otherpsychotic disorders, schizoaffective disorder, autism or autism spectrum disorders,borderline personality disorder, antisocial personality disorder, Tourette'sdisorder, body dysmorphic disorder, hoarding disorder, or psychosurgery, Deep BrainStimulation (DBS) or Electroconvulsive Therapy (ECT); or general medical conditionthat may confound safety and/or efficacy results.

3. Previous treatment in a study with troriluzole