A Phase 3 Study of Lu AA21004 in Patients with Major Depressive Disorder

INTERVENTION: Intervention name : Lu AA21004 Dosage And administration of the intervention : Lu AA21004: 10 and 20 mg QD Control intervention name : Placebo Dosage And administration of the control intervention : Placebo QD CONDITION: Major Depressive Disorder PRIMARY OUTCOME: The change from baseline (i.e. the start of double‐blind treatment) in the MADRS total score after 8 weeks of treatment.; Primary timeframe:8 weeks SECONDARY OUTCOME: *MADRS response (defined as a >= 50% decrease in the MADRS total score from Baseline) after 8 weeks of treatment (Last Observation Carried Forward (LOCF)).; *MADRS remission(defined as a MADRS total score <= 10) after 8 weeks of treatment (LOCF).; *Change from baseline in HAM‐D17 total score after 8 weeks of treatment (LOCF).; *Clinical Global Impression Scale‐Improvement (CGI‐I) score after 8 weeks of treatment (LOCF).; *Change from baseline in CGI‐S score after 8 weeks of treatment (LOCF).; *Change from baseline in Sheehan Disability Scale (SDS) total score after 8 weeks of treatment (LOCF).; *Change from baseline in Digit Symbol Substitution Test (DSST) score after 8 weeks of treatment (LOCF).; *Change from baseline in Perceived Deficits Questionnaire (PDQ‐5) total score after 8 weeks of treatment (LOCF).; Secondary timeframe :8 weeks INCLUSION CRITERIA: *The subject with a primary diagnosis of recurrent MDD according to DSM‐IV‐TR criteria (classification code 296.3x). *The subject is a man or a woman aged between 20 and 75 years (both inclusive). *The reported duration of the subject's current major depressive episode is > = 3 months and < = 12 months. *The subject has a MADRS total score >=26, HAM‐D17 total score >=18 and a Clinical Global Impression‐Severity of Illness (CGI‐S) score >=4.