An inexpensive malaria could be the answer for some women who are not responding to their cancer treatment, according to a promising but preliminary animal study.
In a recent study published in Clinical Cancer Research, researchers discovered the anti-malaria drug hydroxychloroquine (HCQ) can actually reverse drug resistance to the common breast cancer drug, tamoxifen. The researchers inserted cancerous tumors into mice with serious postmenopausal estrogen receptor-positive (ER+) breast cancer. ER+ breast cancers are some of the most common, and are often treated with tamoxifen. However, about 50% of women who are treated with tamoxifen won't respond to the drug or become resistant to it.
HCQ is a drug that was originally developed to treat malaria, but it's also used to treat diseases like lupus and arthritis. The researchers added HCQ to the mice's treatment with tamoxifen and discovered that the malaria did in fact increase tumor responsiveness to the breast cancer drug.
How does it work? The reason some woman become resistant to tamoxifen is that a "pro-survival" cell pathway in the breast cancer cells becomes switched. HCQ turns off the modified cell pathway, which helps prevent resistance to tamoxifen.
It's still early to draw any conclusions on how HCQ could be used clinically for cancer, and so far, research has been reserved in mice. Still, the researchers think it's encouraging that there may be a solution for women not responding to cancer drugs.