Scientists discover novel drug combination with greater benefits for breast cancer patients

04 Jun 2010

A team led by Senior Principal Investigator Dr Lee Soo Chin from the Cancer Science Institute of Singapore (CSI Singapore), NUS, has found a novel combination of drugs that can potentially halve therapy costs and decrease the side effects of treatment for advanced breast cancer patients. The research was published in the leading cancer journal Annals of Oncology on 29 April 2010, and was carried out under the Experimental Therapeutics programme at CSI Singapore.

The researchers combined the anti-fungal drug, ketoconazole, with docetaxel, a chemotherapy drug used in the treatment of breast cancer. Patients were administered a lower dose of docetaxel - they were given only 70 milligrams as opposed to the standard dosage of 120 to 140 milligrams.

Elaborating on the reduced side effects, Dr Lee who is also Senior Consultant at the Department of Haematology Oncology, National University Hospital, said: "One of the main side effects of docetaxel is that it causes white blood cells count to be very low. Low white blood cell count associated with fever is a common complication of chemotherapy and probably the most clinically significant complication." "Some 23 per cent of patients may be admitted to the hospital because of fever associated with low white blood cell count. For patients receiving a lower dose of docetaxel, only three per cent of them were admitted to the hospital," she noted.

Patients can also look forward to reduced therapy cost. Dr Lee explained: "While docetaxel is a commonly used chemotherapy drug, the cost of docetaxel ranges from $1,800 to $2,500 per cycle. But with the new drug combination, it may cost the patient only about S$1,200 to S$1,400, so that would be savings of about 40-50 per cent."

The study also found that there were inter-ethnic differences in the degree of the inhibition of the enzyme CYP3A4 by ketoconazole. Chinese patients were found to respond the most to the addition of ketoconazole, resulting in the slowest breakdown of docetaxel by the body, while Indians responded the least.

Besides breast cancer, the drug combination can also be applied to other cancers such as lung cancer, stomach cancer and prostate cancer.

Moving forward, Dr Lee and team will conduct two additional studies. One study will look at refining the dosage of docetaxel further using the patient's body surface area and a blood protein level that has been shown to influence the rate of elimination of docetaxel from the body. There will also be a healthy volunteer study to further compare the effects of drugs like ketoconazole on important drug metabolising enzymes such as key enzyme CYP3A4 in Chinese, Malays, Indians and Caucasians.