Vanda's insomnia drug works, but not enough

NEW YORK Vanda Pharmaceuticals had to take back a statement released Thursday that the insomnia drug tasimelteon improved sleep; the company saw a 15 percent fall in share price following the news of the retraction.

Trials showed tasimelteon to improve sleep during the first eight nights, but by the 29th night, the benefit compared to placebo had no statistical significance, and patients using the drug didn’t stay asleep any longer than patients in the placebo group.

As of early Friday afternoon, the Thursday press release announcing that tasimelteon significantly improved sleep remained on the Rockville, Md.-based company’s Web site.