The early-phase clinical trial is based on basic research discoveries made in Jonsson Cancer Center laboratories. UCLA researchers have successfully tested the drug in laboratory and animal models. They hope to translate that benefit into patients in the clinic, said Dr. Charles Sawyers, co-principal investigator for the study and the Jonsson Cancer Center scientist whose basic research resulted in the clinical trial.
UCLA laboratory studies have shown that some patients with prostate cancer have lost PTEN, a tumor-suppressor gene. In some patients who have lost PTEN, a gene called mTOR located downstream in the cell-signaling pathway gets turned on and may be driving the cancer. Sawyers, along with co-principal investigator Dr. Robert Reiter, will test a drug called CCI779, which they believe targets mTOR.
"We discovered that tumors missing PTEN seem to be very responsive to CCI779, and it's very clear at a molecular biology level why," Sawyers said. "When you've lost PTEN, mTOR activity gets turned up and tumors become dependent on it for their growth. So a drug that inhibits mTOR should impact the tumor cells but have no effect on the normal cells."
Armed with his laboratory discoveries, Sawyers proposed the prostate cancer study to Wyeth Pharmaceuticals, and the clinical trial was designed. UCLA's Jonsson Cancer Center is the only West Coast site offering this study. Other sites participating include MD Anderson Cancer Center in Texas and Fox Chase Cancer Center in Philadelphia, Sawyers said.
Because CCI779 targets only what is broken in the cancer cell, it is expected to cause very few side effects, Sawyers said.