Conditions: Major Depressive Disorder (MDD)
Keywords: Major Depressive Disorder MDD Depression
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 237
Healthy volunteers: no

Brief summary:
This will be a multicenter, randomized, double-blind study designed to assess the efficacy, safety and tolerability of an oral Aripiprazole/Escitalopram combination therapy in participants with MDD who have demonstrated an incomplete response to a prospective trial of Escitalopram, and report a treatment history for the current MDD episode of an inadequate response to at least one and no more than three adequate trials of an approved antidepressant other than Escitalopram. An inadequate response is defined as less than a 50% reduction in depressive symptom severity as assessed by the participant's self-report on the Massachusetts General Hospital Antidepressant Treatment Response Questionnaire (ATRQ) and evaluated by the investigator as part of the participant's medical and psychiatric history. An adequate trial is defined as an antidepressant treatment for at least 6 weeks duration (or at least 3 weeks for combination treatments) at an approved dose as specified in the ATRQ.

Detailed description:
The study will be organized as follows:

* Screening Phase
* Single-blind Prospective Treatment Phase
* Single-blind Continuation Phase (Responder) or Double-blind Randomization Phase (non-Responder)
* 30 day Post Treatment Follow-up

Assigned Interventions:

* Escitalopram monotherapy
* Aripiprazole/Escitalopram combination therapy
* Aripiprazole monotherapy

Arms:
arm 1: Escitalopram 10 mg capsule, orally, once daily increased to 20 mg/day at the end of Week 1 based upon tolerability profile, plus one matching placebo capsule, for 8 weeks. No dose reductions were allowed after Week 4 and no dose increments were allowed after Week 3. Participants with incomplete response at the end of the Phase B (Week 8) entered Phase C and the rest of the participants continued to Phase B+. arm 2: Participants with response at the end of the Phase B (Week 8) continued treatment with the single-blind escitalopram monotherapy at the dose (10 or 20 mg/day) taken during the final week of Phase B plus one matching placebo capsule, for an additional 6 weeks, in Phase B+. arm 3: Participants with incomplete response at Week 8 who were randomized to this arm group received escitalopram monotherapy 10 or 20 mg capsule, orally, once daily, whichever dose was taken during the final week of Phase B plus one matching placebo capsule for 6 weeks, in Phase C. No dose adjustments were allowed for escitalopram monotherapy during Phase C. arm 4: Participants with incomplete response at Week 8 who were randomized to this arm group received aripiprazole 3, 6, or 12 mg capsule, orally, once daily plus one matching placebo capsule for 6 weeks, in Phase C. Participants were titrated to the aripiprazole target dose of 12 mg/day at Week 9 if the initial 6 mg/day dose was tolerated. No dose increments were allowed after Week 12; however, doses may have been decreased at any week, based upon tolerability. arm 5: Participants with incomplete response at Week 8 who were randomized to this arm group received aripiprazole 3, 6, or 12 mg capsule, orally, once daily in combination with the escitalopram 10 or 20 mg orally, once daily plus one matching placebo capsule for 6 weeks, in Phase C. No dose adjustments were allowed for escitalopram during Phase C. Participants were titrated to the aripiprazole target dose of 12 mg/day at Week 9 if the initial 6 mg/day dose was tolerated.

Interventions: intervention 1: Escitalopram intervention 2: Aripiprazole intervention 3: Placebo
Intervention descriptions: intervention 1: Escitalopram oral capsules. intervention 2: Aripiprazole oral capsules. intervention 3: Study drug matching placebo capsule.

Protocol document: