Safety and Efficacy Study in Patients With Major Depressive Disorder

This is a randomised, multi-centre, double-blind, placebo-controlled, repeat dose, parallel group study in male and female patients with severe depression requiring hospitalization. Efficacy, safety and tolerability will be assessed in three treatment arms. The study will consist of a screening period, a treatment phase (up to 6 weeks) and a post-treatment follow-up visit. The study duration from screening to follow up will be approximately 9 weeks. Subjects who pass screening will be randomized on Day 1 to one of three treatment arms (low dose arm, high dose arm or placebo). Each treatment arm will contain approximately 50 subjects. The subject's depressive symptoms will be assessed using the HAMD17- CR.