Tykerb was tested at UCLA for use in gastric cancers, first in cell lines and animal models, and was shown to be effective in cancers with HER2 amplification. A randomized Phase III clinical trial testing Tykerb with chemotherapy in HER2 amplified gastric cancer patients opened recently and is currently enrolling patients.
Herceptin also has been successfully tested in HER2 amplified gastric cancer patients, Wainberg said, and is expected to be approved for that use by the U.S. Food & Drug Administration within the next six months.
Wainberg said this is the first time that Herceptin and Tykerb have been paired to fight this subset of gastric cancers.
"In our animal models, the mice that received both Herceptin and Tykerb had their tumors shrink down to virtually nothing," Wainberg said. "This suggests that in those tumors that are dependent on HER2 for growth, this combination may be a very effective treatment. The combination of therapies was much better than either Herceptin or Tykerb alone."
The dual blockade works using two mechanisms, blocking cell signaling from inside the cell as well as on the cell's surface. Herceptin, an antibody, blocks growth signals sitting on the surface of the cancer cell, while Tykerb, a tyrosine kinase inhibitor, works from inside the cell to block the signaling that results in out of control growth of the cancer cells.
If just one therapy is used, the cancer cells often can find ways to get around the single blockade, Wainberg said. Using the combination provides a double whammy, and makes it much more difficult for the cancer to circumvent treatment. Herceptin is administered by intravenous infusion, while Tykerb is taken in pill form.
The Jonsson Cancer Center study offers further proof that molecularly targeted therapies those that hone in on what is broken in the cancer cell and leave the healthy tissue unharm
|Contact: Kim Irwin|
University of California - Los Angeles