The breast cancer drug Herceptin has been approved for use on the NHS, under draft guidance issued by the Government's health watchdog today.
The National Institute for Health and Clinical Excellence (Nice) recommended the drug for those with early stage HER2-positive breast cancer, except where there are concerns about the woman's heart function.
The guidance is still open to consultation and a final version will be issued early next month.
The move comes just two weeks after the drug was licensed by the European authorities.
Herceptin is effective on the HER2-positive type of the disease, which affects around 20% to 25% of women newly diagnosed with breast cancer.
Research published in the New England Journal of Medicine last October showed that the drug reduced the risk of disease coming back in women with early-stage HER2 by 46%.
Clinical trials have shown that women taking Herceptin have an 80.6% chance of being alive after three years without recurrence of any cancer.
This compares to 74% for those on a course of treatment other than Herceptin.
Manufacturers Roche, who leaked news of the European approval of the drug last month, said Herceptin had already been used to help treat more than 230,000 women worldwide.
The recommendation is for Herceptin to be given at three-week intervals for one year or until the disease comes back, whichever is the shorter period, as a treatment option for women following surgery, chemotherapy, and radiotherapy (if they have had radiotherapy).
Nice said women with reduced heart function had not been included in clinical trials for the drug, and should not be given it.
The exceptions mean that up to 10% of women who may be eligible for Herceptin will not get it.
The exceptions are:
* Women with left ventricular ejection fraction (LVEF) of less than 55%, or women with a history of documented congestive heart failure - that is, women whose hearts fail to pump adequately
* High-risk uncontrolled irregular heart beat
* Angina in the chest requiring medication
* Heart valve disease
* Heart attack where an area of the heart is not working at all
* Poorly controlled high blood pressure.
Clinical oncologist and Herceptin expert Dr Andrew Wardley said Herceptin is known to exacerbate damage to the heart when it is used in conjunction with the standard chemotherapy treatment, epirubicin.
He said it was hoped that, in the future, there may be a way of avoiding using that treatment, which could lead to greater access for these women.
Nice recommended that cardiac functional assessments should be repeated every three months during treatment with Herceptin.
One year's treatment with Herceptin costs around £20,000 but the Government does not plan to provide extra funding for it.
It says primary care trusts (PCTs) have known about Herceptin for early breast cancer for over a year and have been aware that the Nice guidance was due.
A spokeswoman said: "PCTs should always be planning ahead and we would expect them to consider the implications of introducing all drugs on the horizon, not just Herceptin."
PCTs should also consider issues such as cardiac monitoring and HER2 testing as part of their plans, she added.
Once the final guidance for Herceptin is issued in July, PCTs have a three month "funding direction" to gather their plans.
They do not have to start funding people for treatment until the end of that three-month period, although many are expected to do so.
If after three months, a PCT has not started funding the treatment, it could be subject to legal proceedings.
A spokeswoman for the Department of Health said the best way forward for women currently paying for the drug privately would be decided at a local level.
Factors such as where the woman was in the course of her treatment would be taken into consideration.
Liberal Democrat health spokesman Steve Webb said: "This announcement is very welcome, but it is vital it doesn't turn into another false dawn for women with breast cancer.
"Only this week the Government admitted that over 100 Primary Care Trusts are in the red, so how can we be sure that they have enough money for Herceptin?
"There are existing drugs, approved by Nice, not funded by some health trusts, and it is vital that Herceptin is not added to this list.
"It would be the unkindest cut of all to raise women's hopes only to dash them yet again."Reuse content