Under pressure after the intervention of the Health Secretary, Patricia Hewitt, the North Stoke Primary Care Trust reversed its decision to refuse the £20,000-a-year drug to Elaine Barber, who had announced she would fight her case in the High Court. Ms Barber said she was "over the moon" about the PCT's U-turn. She said: "I hope now that the many women like me who want to be given the chance to live will be given funding for the drug. I can't believe that I have been put through this just so the health authority can balance the books."

A trust spokesman said its chief executive, Mike Ridley, met Ms Barber to discuss her appeal and "in the light of her particular exceptional circumstances" agreed to supply the drug. The original decision to refuse treatment was not based solely on absolute cost but also the efficacy of the treatment, he said.

The trust said there was no contingency budget for Herceptin and the cost would be about £700,000 for the year 2006-07. That would mean a re-assessment of priorities.

The PCT's announcement came just hours after an editorial in The Lancetinsisted that premature decisions were being made about Herceptin's use. The editorial criticised the New England Journal of Medicine, which described Herceptin as "maybe even a cure" last month when it published trials showing that the drug reduced by 50 per cent the chances of cancer returning among some women with early-stage breast cancer.

The Lancet editorial said: "The best that can be said about Herceptin's efficacy and safety for early breast cancer is that the evidence is insufficient to make reliable judgments. It is profoundly misleading to suggest, even rhetorically, that the published data may be indicative of a cure for breast cancer. The debate about the availability of Herceptin to women with early breast cancer demands cooler heads than have so far prevailed, in politics, in public, and even in medical journals."

Last month's findings prompted a wave of demands for the drug, leading countries such as France to bypass normal approval procedure to make it available. It also prompted an order from Ms Hewitt that PCTs should not withhold the drug on grounds of cost alone where a doctor recommended it ­ as Ms Barber's had done. That is particularly difficult for the Stoke PCT, which is £8m in debt and has not budgeted for Herceptin.

The Lancet said crucial overall disease-free survival data was lacking for the drug and it was clear that Herceptin could precipitate heart failure in some patients.

The pharmaceutical company Roche said in response: "There are a number of inaccuracies that appear within the Lancet article. There has been no omission of crucial data in what is the largest-ever study into early stage HER2-positive breast cancer showing that Herceptin halves the risk of cancer. There is a reported 0.5 per cent per cent risk of cardiotoxicity, which in most cases is reversible."