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

The purpose of this study is to evaluate the safety and efficacy in patients with major depressive disorder.

The screening phase is intended for diagnosing and assessing the patient for possible inclusion in the study and for providing an adequate washout period. The following study will be conducted in two parts. Part I is an open-label study, multiple center and dose escalation evaluation in twelve patients. Six subjects each will be evaluated for safety and efficacy assessments at 1 or 2 capsules TID dose for 28 days, sequentially. Each of them will be assessed twice in the first week after administration of PDC-1421 Capsules and once a week in the following treatment.

Part II is a randomized, double-blind, placebo-controlled, parallel-group study. 60 subjects will be randomly assigned on a 1:1:1 basis to one of the three arms (1 PDC-1421 Capsule plus 1 placebo TID, 2 PDC-1421 Capsules TID, 2 placebo TID) for 6 weeks and evaluated the safety and efficacy every two weeks during the treatment period.

Eligibility Criteria:
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.