Efficacy and Safety of Adjunctive Pimavanserin for the Treatment of Schizophrenia (ENHANCE-1)

Inclusion Criteria:

1. Adults patients, between 18 and 55 years of age

2. A clinical diagnosis of schizophrenia with a minimum duration of 1 year

3. The main background antipsychotic with which the subject is being treated must be one
of the antipsychotics listed below:

- Aripiprazole

- Aripiprazole long-acting injectables:

- Abilify Maintena®

- Aristada®

- Risperidone

- Risperidone long-acting injection

- Olanzapine

- Lurasidone

- Cariprazine

- Brexpiprazole

- Asenapine

4. Has had a partial but inadequate response to antipsychotic treatment

5. Has a history of response to antipsychotic treatment other than clozapine

Exclusion Criteria:

1. Patient has a psychiatric disorder other than schizophrenia

2. Patient has a history of resistance to antipsychotic treatment

3. A urine drug screen (UDS) result at Baseline that indicates the presence of any tested
prohibited substance of potential abuse, except marijuana

a. Patients with a result indicating the presence of marijuana are permitted if they
agree to abstain from marijuana use during the study and the medical monitor approves
the subject's participation

4. Patient has current evidence of a serious and/or unstable psychiatric, 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

5. Patient has had a myocardial infarction in the last six months

6. Patient is taking a medication or drug that prolongs the QT interval or has a family
or personal 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).