Herceptin is used to treat breast cancer

Researchers found patents given Herceptin alongside two other chemotherapy agents did no better than those given the two other drugs alone.

But there was a hint that a small number of patients might benefit.

The research, led by a team from Grosshansdorf Hospital, Germany, is published in Annals of Oncology.

In total, more than 100 patients with non-small-cell lung cancer (NSCLC) took part in the trial.

The findings suggested Herceptin may benefit a small group of patients who showed signs of extreme over-activity in a particular gene targetted by the drug.

The researchers say it is this group who should be the focus of further trials. But the numbers are so small it might be difficult to set up these studies.

Disappointing

Herceptin - known technically as trastuzumab - has been shown to be an effective treatment for women with a type of breast cancer associated with over-activity of a gene called HER2.

And it was hoped that it would also work for lung cancer caused by over-activity by the same gene.

Lead researcher Dr Ulrich Gatzemeier: "It was disappointing therefore to find that the survival times and the time to the disease progressing were very similar - between six and seven months for both the trastuzumab and control arms.

"However, we did find that the trastuzumab/chemotherapy combination was well tolerated and that five out of the six patients with extremely high levels of HER2 responded better than other HER2 patients.

"It was nearly eight and half months before their disease progressed compared with just over six months for the patients with less high HER2 levels."

However, Dr Gatzemeier said patients with extremely high HER2 group made up less than 2% of the people who were originally considered for the trial.

The researchers have calculated that herceptin is only likely to benefit less than 5% of patients with advanced NSCLC.

Lung cancer is the second most common form of cancer in the UK after breast cancer.

Smoking and passive smoking cause nine out of ten lung cancers.

Men are more likely to be affected, although the number of women with lung cancer is now increasing.

There are over 38,000 new cases of lung cancer in the UK each year.