An experimental breast cancer drug tested on Australian women significantly slows the growth of aggressive tumours and may be better than current treatment, a study has found.
The study results, presented at an international cancer conference in the US, found that the drug Tykerb combined with the chemotherapy drug Xeloda slowed the progression of the metastatic breast cancer known as HER2+.
About 12,000 Australian women are diagnosed with breast cancer each year, with about 25 per cent developing the HER2+ type with fast-growing tumours and a higher likelihood of relapse.
The international study of 392 women - including 20 from Australia - found that those with this aggressive form, who failed on the available treatment Herceptin, benefited from the treatment.
Tykerb and oral chemotherapy almost doubled the time for disease progression compared to chemotherapy alone, the American Society of Clinical Oncology (ASCO) meeting was told.
It also reduced the risk of cancer spreading to the brain.
Drug company GlaxoSmithKline says it terminated its trial of Tykerb, generically known as lapatinib, early due to its success.
Study co-author Dr Arlene Chan, a medical oncologist at Mount Hospital in Perth, said the drug was expected to be approved in the US in October and Australia would follow soon after.
"On the basis of these results it is likely to registered for women with advanced breast cancer probably towards the end of the year," Dr Chan said.
"The first treatment that is suitable for these women is to receive Herceptin.
"Lapatinib is really for those women who have progressive breast cancer even after this treatment."
Meanwhile, another study presented at ASCO showed Herceptin used following standard chemotherapy reduced the risk of death by 34 per cent for women with early-stage HER2+ breast cancer.
The data also show that Herceptin, known generically as trastuzumab, continued to provide patients with a reduced risk of their cancer coming back.