The breast cancer drug herceptin has finally been approved for general use across England and Wales by the National Institute for clinical excellence.

The drug is suitable for women with advanced metastatic breast cancer and is expected to help around 2,000 women in England and Wales each year costing the NHS around £17 million per annum.

Around one in five women with secondary breast cancer - those with the HER2 metastatic strain - are expected to be to helped by the drug. HER2 positive women have an average life expectancy of less than one year. Whilst Herceptin can prolong life it is not a cure.

Unlike other cancer treatments which attack all cells including healthy ones, Herceptin has fewer side-effects as it targets only cancer cells.

Women will need to be tested twice before they can be prescribed the drug - firstly to see if they carry the HER2 protein and secondly to be given a cardiac test because the drug can cause heart problems.

The HER2 protein - which is found on the surface of breast cancer cells - is believed to increase the speed of tumour growth.

Herceptin (generic name trastuzumab) works by attaching itself to the rogue protein so that the cancer cells cannot divide and grow. It also stimulates the immune system to destroy the cells.

There was much criticism of the length of time which NICE took to approve the drug which has been available for the last 18 months on the continent and for the last five in the USA. The drug - which costs on average £5,300 per patient and £15,500 when prescribed as a combination therapy - was subject to a postcode lottery with certain areas of the country refusing to prescribe it. Some women had spent their life savings funding their own treatment at a cost of up to £700 a week.

The Conservative Health Spokesman, Simon Burns, estimated that around 5,000 women had had either their quality of life or their life expectancy damaged by the length of time during which NICE had taken to complete its appraisal which he described as "cruel and unfair".

However the communications director at NICE, Anne-Toni Rogers, said that whilst she aware of these concerns, it was a decision which NICE did not take lightly. "The decision is incredibly important for women and it was entirely appropriate that we made the right decision based on the right evidence," she said. "We would have obviously like to be in a position to issue the guidance earlier, but to ignore this evidence could have resulted in less robust advice which may not have reflected the true value of Herceptin to the NHS and patients."