NEW YORK (AP) -- Shares of Threshold Pharmaceuticals Inc. tumbled Monday as new clinical data for its most advanced experimental drug disappointed Wall Street.
THE SPARK: Threshold said patients who were treated with a larger dose of TH-302 had median survival of 9.2 months and patients who received a smaller dose lived for 8.7 months. That compared to 6.9 months for patients who were treated with just Gemzar.
The results represented an improvement and Threshold said they are consistent with earlier data from the mid-stage clinical trial. However, the study was not designed to determine if the difference was statistically significant.
THE BIG PICTURE: In February the South San Francisco, Calif., company reported positive results from the trial. It said patients who were treated with TH-302 and Gemzar had better progression-free survival, which is time from the start of treatment until a patient's cancer begins advancing again or the patient dies, than patients who took only Gemzar. The patients who were treated with TH-302 lived about two months longer before disease progression.
Overall and progression-free survival are both measurements that are commonly used in studies of cancer drugs.
Threshold is testing TH-302 as a treatment for soft tissue sarcoma, solid tumors, leukemia, and several other cancers. In early February the company said it would work with Merck KGaA of Germany to develop and market TH-302, and the companies are planning a late-stage study of the drug as a treatment for pancreatic cancer.
SHARE ACTION: Threshold Pharmaceuticals shares lost $1.72, or 19.7 percent, to $7 in midday trading. The stock was trading below $1.50 in early February before the company announced its partnership with Merck KGaA and then reported positive mid-stage study data. On Sept. 5, the stock reached a five-year high of $9.28.