A blood vessel-blocking drug called tasquinimod slowed the rate of disease progression in a clinical trial of 200 prostate cancer patients, according to experts at Johns Hopkins, Roswell Park Cancer Institute, and Duke University. Tasquinimod is an “anti-angiogenesis” drug that cuts off the blood supply to prostate cancers by blocking new blood vessel development. Like all tumors, prostate cancer requires these networks of blood vessels to supply oxygen and nutrients required for growth.

The multicenter trial of tasquinimod took place at seven institutions, including Johns Hopkins School of Medicine, and enrolled prostate cancer patients whose disease had spread.  The patients took a once-daily pill for 4 weeks. At 6 months, 57 percent of men who received tasquinimod had no disease progression, compared to the 33 percent taking a placebo. Overall, the drug added approximately 12 weeks of time that the disease did not worsen, an endpoint known as progression-free survival.

The most common side effects of tasiquinomid observed in the study included gastrointestinal disturbances, fatigue and bone pain. The results were presented at the 2010 annual meeting of the American Society of Clinical Oncology (ASCO), in Chicago.

“Given these results, we feel it is reasonable to move forward with Phase III studies,” says Michael Carducci, M.D., professor at the Johns Hopkins Kimmel Cancer Center, who will lead the next phase of an international study of the drug. “After exploring the drug as a single agent, we may study it in combination approaches with other prostate cancer drugs.”

Research leading to tasquinimod began in the early 1990s when John Isaacs, Ph.D., a professor at the Johns Hopkins Kimmel Cancer Center, found that a drug called linomide, which had been previously tested in multiple sclerosis, restricted blood supply to prostate tumors. However, the linomide’s side effects were too toxic for humans, so Isaacs, in collaboration with the pharmaceutical company Active Biotech, identified a related molecule, tasquinimod, for clinical testing after finding it had the same cancer starving activity but with less toxicity.

Isaacs says that tasquinimod works by stopping new blood vessel development around the tumor, but does not make the cancer disappear. “The idea for anti-angiogenesis drugs is not to prevent tumors from developing; rit is to stabilize disease,” says Isaacs, who is conducting additional laboratory studies to identify the drug’s precise cellular target.