Both the Scottish Medicines Consortium (SMC), this country's drugs watchdog, and the National Institute for Health and Clinical Excellence (Nice), the equivalent body in England and Wales, have rejected Tyverb's use by the NHS.
The manufacturer, GlaxoSmithKline (GSK), said it hoped Nice would reconsider. If Nice does change its mind, the SMC is likely to follow suit.
GSK had offered to fund a 12-week programme to show the drug's effectiveness at prolonging life, and said the NHS would only then have to pay for those patients who were still benefiting from Tyverb after 12 weeks. But Nice rejected the plan as it published its final appraisal, concluding it was not a cost- effective use of NHS resources.
Tyverb is designed to help about 2,000 women in the UK each year whose cancer returns despite treatment with standard chemotherapies and the drug Herceptin. Tyverb is not a cure, but can delay the cancer's progression.
Simon Jose, general manager of GSK in the UK, said: "We recognise that Nice has some tough funding decisions to make, but urge it to reconsider."
Four weeks' worth of tablets cost 1,608, according to GSK, and a series of considerations are taken into account by Nice to assess cost-effectiveness.
The Nice recommendation suggested the cost for patients would be around 70,000 a year. However, GSK produced a figure of 16,000 and also pointed out that it helped control the disease in women after standard chemotherapy and treatment with trastuzumab (Herceptin) had failed to stop it returning.
The company also argued 16 other European countries, including Ireland, France and Germany, had granted funding for the drug.
Two years ago, manufacturers of and patients using Alimta, a drug used to treat Alzheimer's disease, won their appeal against Nice's ruling that the medicine was not cost-effective.
The case went to a judicial review at the High Court in London, which found in favour of Alimta's supporters.
Meanwhile, scientists have found two genetic links to breast cancer – one increasing the risk and the other reducing it.
Two regions of DNA were identified that are believed to contain mutant genes influencing susceptibility to the disease.
One gene appears to raise breast cancer risk by as much as 23 per cent. The other mutation seems to have a protective effect, lowering the risk of developing the disease by up to 11 per cent.
The new research brings the total number of known genetic variants that alter breast cancer risk to 13.
The international study led by Cancer Research UK involved more than 100 scientists from 16 countries.
Breast cancer is the most common cancer in the UK, with more than 45,500 new cases diagnosed each year.