A recent report suggests that treatment with a combination of two commonly used anti-cancer drugs, doxorubicin and zoledronic acid, may benefit women with breast cancer. Doxorubicin is an anthracycline antibiotic that is widely used in cancer chemotherapy. It is thought to work by intercalating DNA and preventing cell replication.
Zoledronic acid is a third generation bisphosphonate that is used to prevent fractures in cancer patients with bone metastases. The bone destruction associated with malignancy develops because tumor cells synthesize and release soluble factors that stimulate osteoclasts to resorb bone. The bisphosphonate drugs act by inhibiting osteoclast function.
Zoledronic acid and other bisphosphonates are also used to treat osteoporosis – a single dose of zoledronic acid has been shown to increase bone mineral density for up to a year.
The new study looked at the effects of the two drugs given alone, sequentially , or in combination on the growth of established breast tumours in mice. Alone out of the treatment methods, doxorubicin followed 24 hours later by zoledronic acid almost completely abolished tumor growth in the absence of bone disease. Zoledronic acid has already been shown to reduce the risks of fractures in breast cancer patients with bone metastases and the new study provides hope that new dosing regimens may provide additional benefits.