Scientists in the US have demonstrated how Roche's drug Erivedge (vismodegib) could act as a targeted therapy for breast cancer.
A study conducted by researchers at the Ohio State University Comprehensive Cancer Center (OSUCCC) showed that vismodegib, which is currently undergoing clinical trials for other types of cancer, inhibits the growth of breast cancer tumours which are resistant to tamoxifen, a popular hormonal therapy used to block oestrogen.
The team found that the drug is able to block a signaling pathway known as hedgehog (Hhg) which, when activated, renders tamoxifen treatment ineffective and enables the growth of breast cancer cells.
More than two-thirds of breast cancer cases show high levels of the estrogen receptor. Tamoxifen is often prescribed to treat ER-positive tumours and has improved the disease-free survival of people with ER-positive breast cancer by 50%.
But, according to OSUCCC medical oncologist Dr Bhuvaneswari Ramaswamy, up to 40% of patients taking tamoxifen become resistant to it after about five years.
"Our findings suggest that we can target this pathway in patients with estrogen-receptor breast cancers who have failed tamoxifen therapy," said Ramaswamy.
The scientists found that targeting the Hhg pathway alone or in combination with another pathway, known as PI3K/AKT, could be a novel therapeutic option for treating tamoxifen-resistant breast cancer.
Ramaswamy noted, "These agents we have identified are all in clinical development for other kinds of cancer."
Approximately 230,000 new cases of breast cancer are expected in the US in 2012, and almost 40,000 Americans will die from the disease.
Image: Tamoxifen (Nolvadex) is rendered ineffective if the a signaling pathway known as hedgehog is activated. Photo: Courtesy of Editor182.