A Study to Determine the Safety, Tolerability and Efficacy NW-3509A in Patients With Chronic Schizophrenia

This is a prospective, 4-week, randomized, double-blind, placebo-controlled, study designed
to evaluate the safety, tolerability, and preliminary efficacy of an oral dose range of
NW-3509A of 30 to 50 mg/day (15 to 25 mg, BID) in patients with chronic schizophrenia on a
stable dose of an antipsychotic (aripiprazole or risperidone). A minimum of 90 patients will
be randomized in a 1:1 ratio to receive either NW-3509A (n=45) or placebo (n=45). Dose
increases will be performed only during in-patient setting.

Safety and efficacy assessments will be done on a weekly basis during the randomized
treatment period. The assessment of safety will be based on laboratory tests (biochemistry,
hematology, and urinalysis), 12-lead standard ECG, vital signs, physical examinations,
neurological examinations, C-SSRS, ESRS-A, subjective reporting of any AE by the subject,
objective observation of any AE by the Investigator. Pharmacokinetic samples will be taken
at various time-points. Efficacy assessments will include the PANSS, CGI-C, CGI-S and the
Strauss-Carpenter Level of Functioning (LOF) scale.

Inclusion Criteria:

1. Male/female; if female, must not of childbearing potential

2. 18 to 65 years of age, inclusive;

3. Has a current diagnosis of schizophrenia

4. Has a total score on the PANSS < 75.

5. Positive symptoms sub-scale score not to exceed 15; score of ≥4 on no more than 2
positive symptoms

6. Has a Clinical Global Impression - Severity of disease (CGI-S) rating of mildly to
moderately severely ill.

7. Is in need of anti-psychotic treatment and is currently receiving a stable dose
(minimally for 4 weeks prior to screening of oral risperidone or aripiprazole (at
least 2 mg risperidone dose-equivalent).

8. Current symptoms present for at least one month.

9. Patient agrees to be hospitalized for up to 2 days at the start of dosing and at each
dose increase