Article from - Channel NewsAsia online 01 Jun, 2010

Singapore researchers have made a breakthrough in the treatment of breast cancer.

They have found a new combination of drugs that promises to cut the costs of therapy and reduce the side effects.

Two years of hard work have finally paid off.

A clinical study - conducted between July 2005 and September 2006, and involving 30 patients - by the Cancer Science Institute of Singapore has yielded promising results, by combining two common drugs to treat breast cancer.

Local researchers found that by giving patients a three-day course of an anti-fungal drug known as ketoconazole, they were able to reduce the dosage of the chemotherapy drug, docetaxel, by half.

The anti-fungal drug stops a key enzyme (CYP3A4) from causing the body to break down docetaxel.

This new treatment was observed to be as effective as giving patients only docetaxel at higher doses.

A standard treatment course of docetaxel alone would require about 120 to 140 milligrams. But by combining the drugs, patients are only administered 70 milligrams.

As the chemotherapy drug is expensive, a reduced dosage means cost savings for patients.

Dr Lee Soo Chin, principal investigator, Cancer Science Institute of Singapore, said: "Each cycle of this chemotherapy, if given in standard doses, would probably cost the patient approximately S$1,800 to S$2,500 every three weeks, but with the new combination, because of the lower dose, 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."

By combining the two drugs, patients were also found to have fewer side effects. For example, 70 per cent of breast cancer patients who are given the standard dosage of docetaxel suffer from extremely low blood counts. But with the new drug combination, only 30 per cent of patients were found to have suffered from this side effect.

Inter-ethnic differences also emerged from the study. Chinese patients responded the most to the addition of the anti-fungal drug, resulting in the slowest breakdown of docetaxel by the body, while Indians responded the least.

Dr Lee said the drug combination could potentially be used to treat other cancers, such as lung, stomach and prostate cancers. But Dr Lee cautioned that the drugs may not be suitable for patients with poor liver function.

The research team said that two more studies are in the pipeline. The first study will look at how a patient's body surface area and blood protein level influence the breakdown of docetaxel, and adjust the dosage of the drug accordingly.

In the second study, the team will recruit 72 healthy volunteers across the four races - Chinese, Malay, Indian, Caucasian - to compare the effects of ketoconazole on the key enzyme CYP3A4. - CNA/ms