The design of the Phase IIb trial of TC-5214 includes two phases. In the first phase, subjects diagnosed with major depressive disorder (MDD) will receive citalopram hydrobromide, a selective serotonin reuptake inhibitor, for eight weeks to determine the extent of therapeutic response.
Subjects who have not responded well based on predefined criteria would be randomized into the double blind second phase of the trial and receive either TC-5214 or placebo, together with continued citalopram therapy, for an additional eight weeks.
It is expected that approximately 560 subjects will participate in the first phase of the trial and approximately 220 subjects will be randomized into the second phase of the trial.
The primary endpoint of the trial is change from baseline during the second phase of the trial as measured by the Hamilton depression rating scale. The trial will also collect information on a variety of secondary safety and efficacy measures. The trial is planned to be conducted at sites in the US and India.