Drug combination offers breast cancer hope
Scientists found the two drugs acted together to slow down the growth of tumours. In mice given the therapy, growing breast tumours were almost stopped in their tracks.
The therapy involves the breast cancer chemotherapy agent doxorubicin and the bisphosphonate drug zoledronic acid.
In the research, doxorubicin was given to the mice first, followed 24 hours later by zoledronic acid. When the order was reversed, or the drugs administered on their own, the treatment had little effect.
The chemotherapy drug appeared to “prime” the tumour and make it sensitive to the bisphosphonate.
Tests showed the treatment triggered apoptosis in the cancer cells, causing them to self-destruct.
It also blocked angiogenesis, the process by which blood vessels are created that fuel tumours with oxygen and nutrients.
A clinical trial is underway which could lead to the treatment becoming widely available. Since both drugs are well-established and only need the terms of their use to be changed, this may not take long.
The researchers, from the University of Sheffield and Kuopio University in Finland, wrote in the Journal of the National Cancer Institute: “Tumour growth was almost completely abolished in mice treated with doxorubicin followed 24 hours later by zoledronic acid.”
Bisphosphonates are used to prevent bone thinning in osteoporosis patients.
They have also been shown to protect the bones from the destructive effects of tumours. For this reason they are sometimes given to men with prostate cancer, which has a habit of spreading to the bones.
However the new study showed zoledronic acid can have a powerful direct effect on breast cancer without any bone involvement. The cancer cells used had no particular affinity for bone.
Patients are receiving the treatment in a large trial led by one of the Sheffield scientists, Professor Robert Coleman.
The results should be known later this year.
