Experimental Drug Shrinks Breast Tumors
New Drug Wipes Out Cancer Stem Cells That Fuel Tumor Growth
Cancer Stem Cells Drop, Breast Tumors Shrink continued...
Chang theorized that shutting down the Notch pathway would deplete the supplies of cancer stem cells.
So she then tested the new compound [GSI] which is known to block the Notch pathway in mice that grew human tumors. It worked. The number of cancer stem cells that would otherwise have remained dropped.
Now, Chang and colleagues are testing the drug, in combination with a commonly used chemotherapy drug, in women with advanced breast cancer. So far, 35 women have been treated in the ongoing study.
Tissue samples after treatment showed a dramatic drop in the number of stem cells. And after several rounds of treatment, tumors started to shrink, she tells WebMD.
The chemo attacks the ordinary tumor cells, and the experimental compound goes after the breast cancer stem cells, Chang explains.
This study was funded by Merck & Co. which makes the experimental GSI used in the study.
Osborne says that Baylor researchers are also testing a Notch inhibitor in people with leukemia. "In the first patient, we saw a dramatic decrease in cancer stem cells. Then after two to three months, as the mother cells were depleted, the patient began to get better," he says.
William Gradishar, MD, a breast cancer expert at Northwestern University, tells WebMD that while current therapies shrink advanced tumors, they eventually start growing again.
"That's because they are not targeting these cancer stem cells. So this appears to be an effective approach," he says.
The next step is larger studies pitting the combination treatment against standard treatment in women with advanced breast cancer, Chang says.
Eventually the researchers hope to test the treatment to women with early-stage breast cancer, where there is better chance of a cure, she adds.
Other Breast Cancer Drugs in Pipeline
At the meeting, Gradishar reported that adding the cancer drug Nexavar to standard chemotherapy extends the time until advanced breast cancer progresses.
In the study of 220 women, tumors shrank in two-thirds of those treated with the Nexavar plus Taxol compared with about half of those treated with Taxol alone.