Depomed Trial Disappoints; Shares Plunge

(Updates stock price and provides further detail from the company's press release announcing the results.)

MENLO PARK, Calif. (TheStreet) -- Depomed(DEPO Quote) released disappointing results Monday for a phase-3 clinical trial of Serada, a treatment for hot flashes caused by menopause.

Investors reacted swiftly, sending shares of the company down 33%, or $2.12, to $4.24 in early trading Monday. In the first 15 minutes of trading, volume reached 1.5 million shares; turnover in Depomed issues averages 450,000 shares a day.

The study was meant to evaluate the safety and efficacy of the Serada drug. According to a press released issued by Depomed Monday morning, the company said an 1800 milligram dose of Serada "achieved positive results" in patients after four weeks of treatment.

After 12 weeks, however, three out of four of the endpoints, or goals, of the treatment "did not achieve statistical significance" compared with the control group. A fourth endpoint did show a positive result, Depomed said.

The goals of the treatment included decreasing the frequency and severity of hot flashes against a placebo after four and 12 weeks of treatment. Depomed didn't specificy which endpoints Serada failed to achieve and which it did in the 12-week portion of the study.