said Thursday that an experimental stroke-treatment drug failed to achieve its goal in a late-stage clinical trial.
The company and its development partner, Germany's
, said the drug desmoteplase didn't outperform a placebo in assessing how patients responded after receiving the drug within three to nine hours of exhibiting symptoms.
"These data are surprising and are not consistent with previously observed patterns in
other clinical trials and larger size, placebo-controlled acute stroke trials," the companies said in a press release issued after the market had closed. "The absence of consistency with previous findings is not easy to explain, but in-depth analyses are planned to better understand the data."
Forest said it will review the study "over the coming weeks to determine the appropriate next steps and its role regarding U.S. development" of the drug. Shares of Forest fell 2.4% in late trading.
Desmoteplase is a genetically engineered clot-dissolver derived from the saliva of a vampire bat, and it is one of several experimental compounds that Forest has cited as potential, big contributors to future sales.
These compounds will take on
extra importance early in the next decade when Forest's two best-sellers -- the antidepressant Lexapro and the Alzheimer's disease drug Namenda -- lose patent protection. They now account for 80% of total revenue.
Last week, Forest reported
better news for milnacipran, an experimental drug for fibromyalgia syndrome. This treatment for chronic pain achieved its goal in a late-stage clinical trial, according to preliminary results. If Forest confirms these results after a more detailed analysis, it plans to seek U.S. approval by year-end.
In the stroke drug test involving 186 people, patients were evaluated after 90 days for clinical improvement. Researchers said 36.4% patients receiving a higher dose demonstrated improvement vs. 47.4% for those receiving a lower dose and 46% getting a placebo. Neither dose was statistically superior to the placebo.
The study looked at people with acute ischemic stroke, the blocking of an artery in the brain. Arteries bring fresh blood from the heart and lungs, and the blood carries oxygen and nutrients to the brain. Because blockages cause brain cells to die, quick treatment is necessary.