Targacept ( TRGT) said Wednesday that its experimental drug TC-5214 was able to improve the symptoms of depression in patients who don't respond well to a currently prescribed drug, according to results from a phase II study.

The positive news sent shares of the Winston-Salem, N.C-based drugmaker sharply higher in pre-market trading.

In the phase IIb study, patients treated with the combination of TC-5214 plus Celexa, an anti-depressant marketed by Forest Labs ( FRX), demonstrated statistically significant improvement in their depression rating scores compared to patients treated with a placebo plus Celexa, the company said.

Patients in the study were diagnosed with major depressive disorder but did not respond adequately to Celexa. These patients were then randomized to receive TC-5214 or a placebo while remaining on Celexa.

"It is particularly compelling that the superiority of TC-5214 as augmentation to citalopram over citalopram alone was first seen after only two weeks and grew steadily over the trial's last six weeks, culminating in remission for twice as many subjects in the TC-5214 group," said Dr. Madhukar H. Trivedi, a professor at the University of Texas Southwestern Medical Center at Dallas and one of the principal investigators for the TC-5214 trial. Citalopram is the scientific name for Celexa.

The phase IIb study was conducted at 20 sites in India and three sites in the U.S. The most frequent adverse events in the study were headache, dizziness and constipation but there was no significant difference between the dose groups in discontinuations due to adverse events.

One patient reported a seizure that was deemed by investigators to be related to either Celexa or TC-5214.

Targacept said it was actively seeking a partner to further the development of TC-5214, with phase III studies to start in the second quarter 2010.

Targacept shares were up 87.3% to $5.73 in recent trading.

Adam Feuerstein writes regularly for TheStreet.com. In keeping with TSC's editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet.com. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.

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