was down 54.1% in premarket Instinet trading, a day after the company said an advanced clinical trial of the Xcytrin injection, a proposed treatment for cancer that has spread to the brain from another part of the body,
failed to produce positive results.
Investors started fleeing after the close Thursday. Pharmacyclics said the trial was designed to compare the safety and effectiveness of standard whole-brain radiation therapy alone to radiation therapy with the addition of Xcytrin.
The use of the injection, according to the company, didn't increase longevity or affect patients' quality of life with any statistical significance. Shares of Pharmacyclics were trading at $10 before the bell, after closing the previous regular session at $21.70.