A new breakthrough drug that cuts the risk of dying early by one-third for women with an aggressive form of breast cancer was developed by researchers.
Women on combination treatment of pertuzumab alongside the 'wonder' drug Herceptin and chemotherapy lived on average for 18 months without their disease worsening, compared with 12 months for those not taking it.
Doctors are hailing the Herceptin-plus combination, saying it will change treatment in the same way Herceptin did five years ago.
The new drug should be licensed in the Spring making it available for specialists to prescribe three-weekly infusions.
Around 10,000 of the 48,000 British women diagnosed with breast cancer each year have the HER2 positive form, which is more aggressive.
When the disease starts to spread they are prescribed Herceptin which holds the disease at bay for around a year - six months longer than chemotherapy alone.
But, according to the findings of the study, now pertuzumab, also known as Perjeta, can give the same benefit again.
They showed that the risk of death over the course of the study was reduced by 34 per cent in patients receiving the Herceptin-plus combination.
They lived on average 18.5 months before the disease worsened, compared with 12.4 months for women on Herceptin and chemotherapy.
Doctors are hailing the Herceptin-plus combination, saying it will change cancer treatment in the same way Herceptin did five years ago
The Cleopatra study of 800 women included Britons whose HER2 positive cancer was spreading.
It was stopped early because the results were so positive in order that women on standard treatment could get the new drug as well.
"This drug is keeping women alive longer and they have a good quality of life," the Daily Mail quoted Dr David Miles from Mount Vernon Cancer Centre as saying.
"It is rare in a career to see two new drugs come along that change the way we treat breast cancer. I've seen the disease getting worse in front of me and then women recovering when they have pertuzumab.
"Over the last decade women with this form of breast cancer are living at least a year longer on average than they would have done and some are having their lives considerably extended," Miles said.
The new breakthrough drug cuts the risk of dying early by one-third for women with an aggressive form of breast cancer
About four out of five patients positively respond to the drug, with most of the remaining patients having their disease stabilised with few side effects, he said.
Both pertuzumab and Herceptin are antibody therapies which work by binding to the part of the tumour essential for growth, preventing cell division.
This causes the tumour to stop growing or even shrink.
The findings have been presented at the San Antonio Breast Cancer Symposium, Texas.