A skin cancer drug developed by Roche's ($RHHBY) Genentech appears to beat back breast cancer cells resistant to tamoxifen, a standard course of treatment, researchers from Ohio have discovered. They also figured out how those cells resistant to tamoxifen both grow and multiply.
Bhuvaneswari Ramaswamy and Sarmila Majumder of the Ohio State University Comprehensive Cancer Center made the finding, which is detailed in the journal Cancer Research.
It turns out that tumors in 30% of patients with estrogen-sensitive breast cancer eventually resist tamoxifen treatment. And the research team proceeded to figure out why. Those cells, it seems, depend on the hedgehog and PI3K/AKT signaling pathways for growth. But the researchers determined that the Roche/Genentech drug Erivedge (vismodegib) may be a solution. The drug, which gained regulatory approval last year as a treatment for advanced basal cell carcinoma, blocks the hedgehog pathway, for one thing. And in animal tests, it stopped tamoxifen-resistant human breast tumors from growing.
On a hopeful note, the scientists think the drug could work well against tamoxifen-resistant breast cancer tumors as part of a combination targeted therapy that relies on both hedgehog and PI3K inhibitors, with no need for subsequent chemotherapy. Chemo is a typical fall-back option for tamoxifen-resistant tumors, but patients suffer from plenty of side effects. While this option may be a long way from tests in humans, the notion that Erivedge/vismodegib could work as a treatment for tamoxifen-resistant breast cancer is tantalizing. After all, at least 30% of patients who take tamoxifen become resistant to it in 5 years, the researchers note, leaving them with chemotherapy as their only option. Those patients could certainly use another weapon for their cancer fight.
- read the release
- check out the journal abstract
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Editor's note: This story has been updated in the third paragraph to note vismodegib is approved for advanced basal cell carcinoma.
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