Herceptin improves some breast cancer survival rates
Around 25 per cent of breast cancer patients can benefit from herceptin for at least two years of treatment, researchers at London's Royal Marsden hospital have said.
The study found that the drug was of benefit to the quarter of breast cancer patients with early cases of the HER2- positive, or oestrogen sensitive, form of the disease.
Herceptin was found to reduce mortality rates among this group by 1.8 per cent, or by around one in every 55 cases over the two years of the trial.
The drug did not prevent tumours from returning after the trial period, however, and was also associated with heart irregularities, said Professor John Toy of Cancer Research UK.
"The benefit of herceptin gradually diminished after stopping treatment, and serious side effects occurred more often in the women who received the drug," he added.
"So although herceptin is clearly a valuable new treatment, questions remain about how long it's best to prescribe it for and how best to combine it with other breast cancer treatments.
"These findings add weight to the evidence that molecular cancer treatments like herceptin - which target cancer cells - are effective and hold great promise for the future."
Herceptin was approved for use among early-stage breast cancer patients by regulators last summer but some studies have questioned the benefits claimed for it.
The study is published in the Lancet.