A Phase II Study of PDC-1421 Capsule to Evaluate the Safety and Efficacy in Patients With Major Depressive Disorder

Inclusion Criteria:

1. Outpatients aged 20-65 years

2. Subjects must be able to understand and willing to sign informed consent

3. Female subjects of child-bearing potential must test negative to pregnancy and use
appropriate birth control method from the beginning of study to the 15 days later
after ending of study

4. Met criteria for MDD without psychotic features as defined by the Diagnostic and
Statistical Manual of Mental Disorders, Fourth Edition Text Revision® (DSM-IV-TR) and
confirmed by use of the Mini International Neuropsychiatric Interview (MINI).

5. 17-item HAM-D (Hamilton Rating Scale for Depression) total score ≧20 and CGI
(Clinical Global Impression) total score ≧4

Exclusion Criteria:

1. Have a current or previous major psychiatric disorders which be defined to be per the
DSM-IV-TR, including obsessive-compulsive disorder, posttraumatic stress disorder,
bipolar I or II, manic or hypomanic episode, schizophrenia, major Axis II disorders
which might compromise the study, and major depression with psychotic symptoms,
mental retardation.

2. Use of any treatment for MDD in the last 2 weeks before visit 1 (4 weeks for
fluoxetine).

3. Use of psychoactive drugs within the last 2 weeks before visit 1 other than that
subjects had insomnia who need the treatment as determined by the Investigator.

4. Subjects who were non-responsive to two or more courses of antidepressant medications
given an adequate dosage for symptom treatment within four weeks, or by the judgment
of the investigator considered to have treatment resistant depression (TRD), or a
history of electroconvulsive therapy (ECT), transcranial magnetic stimulation (TMS)
or psychosurgery within the last year.

5. Have a history of any seizure disorder.

6. Any clinically significant abnormal vital sign, ECG, laboratory values as determined
by the investigator which might interfere with the study.

7. Any organic disorder caused u medical related depression which cannot be under
well-controlled such as clinically significant in neurological, gastrointestinal,
renal, hepatic, cardiovascular, respiratory, metabolic, endocrine, hematological or
other major disorders

8. Have a high suicidal risk as measured by MINI.

9. Have a history of substance abuse within the past 6 months or a positive urine drug
screen for any substance of abuse at visit 1.

10. Have a history of severe allergies to more than 1 class of medication or multiple
adverse drug reactions.