By Ransdell Pierson
(Reuters) - An experimental therapeutic vaccine from Danish drugmaker Bavarian Nordic helped significantly extend survival in patients with advanced prostate cancer, according to results of a small early-stage trial conducted by the U.S. National Cancer Institute.
Shares of Bavarian Nordic closed up almost 12 percent in Copenhagen after the company released the data on Tuesday.
The study involved 30 patients with prostate cancer that had failed to benefit from standard treatments that reduce levels of testosterone, the male hormone that fuels the cancer.
Patients were treated with the company's Prostvac vaccine, in addition to escalating doses of Bristol-Myers Squibb Co's Yervoy, an approved injectable treatment for advanced melanoma that works by taking the brakes off the body's immune system.
On average, patients taking both drugs survived 31.3 months, compared with a predicted survival period of 18.5 months that had been based on historical survival data for older chemotherapy treatments.
Among the 15 patients who received the highest 10 milligram dose of Yervoy in combination with Prostvac, 20 percent remained alive at 80 months.
Data from the combination trial were especially impressive, considering that Yervoy had previously failed in Bristol-Myers' own trials to prolong survival in patients with advanced prostate cancer.
Yervoy and an emerging group of immuno-oncology drugs called PD-1 inhibitors from Bristol-Myers, Merck & Co and other drugmakers are expected to have greatest effectiveness when used in combination. The PD1-inhibitors make cancer cells more visible to the immune system, removing their natural camouflage.
Complete data from the Prostvac study are slated to be presented on Thursday at the Genitourinary Cancers Symposium in Orlando.
The vaccine is designed to trigger an immune system response against prostate cancer cells.
(Reporting by Ransdell Pierson; Additional reporting by Bill Berkrot; Editing by Marguerita Choy)