Study to Evaluate the Efficacy and Safety of Adjunctive Pimavanserin in Major Depressive Disorder (CLARITY)

A Phase 2, Multicenter, Randomized, Double-blind, Placebo-controlled, Study to Evaluate the Efficacy and Safety of Adjunctive Pimavanserin in Major Depressive Disorder

To assess the efficacy of pimavanserin compared to placebo when given adjunctively to a selective serotonin reuptake inhibitor (SSRI)/serotonin-norepinephrine reuptake inhibitor (SNRI) antidepressant as treatment of patients with Major Depressive Disorder (MDD) and an inadequate response to antidepressant therapy

Inclusion Criteria:

1. Adult patients, aged 18 years and above

2. A clinical diagnosis of major depressive disorder (MDD)

3. Is being treated with one of the following SSRI or SNRI antidepressants as monotherapy:

   • Citalopram
   • Escitalopram
   • Paroxetine
   • Fluoxetine
   • Sertraline
   • Duloxetine
   • Venlafaxine
   • Desvenlafaxine
   • Venlafaxine XR

4. Has a history of inadequate response to antidepressant treatments

Exclusion Criteria:

1. Patient has a psychotic disorder other than MDD
2. Patient has current evidence of a serious and/or unstable neurologic, cardiovascular, respiratory, gastrointestinal, renal, hepatic, hematologic, or other medical disorder, including cancer or malignancies, which would affect the patient's ability to participate in the program
3. Patient has a history or symptoms of long QT syndrome

Patients will be evaluated at screening to ensure that all criteria for study participation are met. Patients may be excluded from the study based on these assessments (and specifically if it is determined that their baseline health and psychiatric condition do not meet all pre-specified entry criteria).