Doxorubicin coated in tiny droplets of oil is as effective as the standard formulation but much less toxic when used to treat women with advanced breast cancer. Doxorubicin(Drug information on doxorubicin) is known to cause damage to individual muscles and the blood vessels of the heart, thereby raising the risk of heart failure to as high as 5% in patients receiving the maximum recommended dose. According to a recent study, surrounding doxorubicin by protective liposomes allows it to flow through the heart without dissolving, thus lowering the risk of heart damage.
Passes Through the Heart
In a phase III clinical trial in 297 patients, only 6% of those with metastasized breast cancer developed cardiotoxicity when treated with a liposome-encapsulated doxorubicin preparation known as Myocet (approved for use in Europe but investigational in the United States and Canada),* compared to 21% of those treated with standard doxorubicin. Both groups of patients also received cyclophosphamide(Drug information on cyclophosphamide) (Cytoxan, Neosar), and both had equivalent response rates.
"Liposome-encapsulated doxorubicin passes right through the heart and lodges in organs such as the liver and in the blood vessels that feed tumors, and then slowly dissolves, allowing the doxorubicin to fight the cancer cells," said the study’s lead author Gerald Batist, MD, a professor at McGill University and director of the Center for Translational Research in Cancer at Jewish General Hospital, Montreal, Quebec.
This means physicians may be able to treat patients with the liposomal formulation of doxorubicin for longer periods than is now possible with the standard formulation. "Although doxorubicin is the single most active treatment for breast cancer, it comes with a risk of cardiotoxicity, and the more it is used, the greater the risk," said Dr. Batist. "By using liposome-encapsulated doxorubicin, patients may be able to stay on treatment longer or receive additional treatment if their cancer recurs, while reducing their risk of cardiotoxicity."
* Liposomal doxorubicin is available as Doxil in the United States.