The body which approves drugs for use by the NHS in Scotland has rejected an "extremely effective" breast cancer treatment for the third time.

The Scottish Medicines Consortium (SMC) said Perjeta is "very expensive" and it does not believe it would be a "good use of limited NHS resources".

With the drug already available to patients in England, campaigners branded the decision "bitterly disappointing".

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Perjeta, which is also known as pertuzumab, can extend the life of patients with advanced breast cancer by almost 16 months, according to manufacturers Roche.

Single mother Alison Tait, from Edinburgh, has been receiving the drug thanks to medical insurance, but is now frightened for her future.

She said: "I know that I'm very fortunate to be able to access Perjeta but I worry about the future. My health insurance company has agreed to fund the drug for a year but I'm not sure what will happen after this point. It's frightening.

"Being there for my daughter Ellen is everything to me. It's just the two of us and she needs me. The SMC's decision to decline Perjeta is a huge blow for women like me - and it has massive implications for me and my family.

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"I know that nothing in life is a sure thing but I deserve the chance to live. How can the SMC and Roche put a price on my life like this?"

SMC chairman Dr Alan MacDonald said: "Unfortunately the committee was unable to accept pertuzumab for routine use."

He said while there was "strong support" for the medicine from doctors and patients, the SMC did not consider the treatment "would be a good use of limited NHS resources".

Dr MacDonald said: "We know this decision will be disappointing to patients and their families as we understand how devastating breast cancer can be. However, when we make our decisions we have to take account of the needs of all patients who require treatment by NHS Scotland, not just those who would benefit from the medicine under consideration."

Pharmaceutical firm Roche UK insisted it had done "everything in its power" to make the drug cost effective for NHS Scotland.

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More than 4,500 Scots are diagnosed with breast cancer every year - with approximately 15% of them suffering from the aggressive HER2 positive form of the disease, which can be treated with Perjeta.

Mary Allison, Breast Cancer Now's director for Scotland, said: "This is a bitterly disappointing decision for women with incurable HER2 positive secondary breast cancer in Scotland.

"Perjeta is a targeted medicine that can give these women nearly 16 months of good quality extra time to live. That's more precious time with the ones they love.

"The consequences of today's decision cannot be underestimated. Patients will miss out on a medicine that could keep them alive for significantly longer. They, and their loved ones, will now have no choice but to pay for this drug themselves or appeal to the NHS individually to receive it.

"This is now the third time that this extremely effective drug has been rejected by the SMC. We now urge the SMC and Roche to come together with us to discuss what needs to happen to ensure this life-extending treatment can be made available to patients in Scotland."

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Gregor McNie, of Cancer Research UK, said: "It's disappointing that SMC hasn't recommended Perjeta as a treatment for patients with breast cancer in Scotland.

"Breast cancer is the most common cancer among women in Scotland and this drug could have been offered as a possible treatment for some patients with advanced HER2 positive breast cancer.

"We hope that SMC and the drug company will be able to work together to make this treatment available to patients in the future."

Nicolas White, head of Breast Cancer Care Scotland, said: "This short-sighted decision denies women and men in Scotland living with incurable breast cancer the chance of an extra year to live - time to be there with loved ones for the moments that matter is irreplaceable.

"Women and men with incurable breast cancer hold out hope for this sort of breakthrough. And those recently diagnosed who could have had this treatment will be heartbroken by today's news.

"The current one-dimensional assessment of medicines is blocking access to pioneering combinations of treatments. We urgently need to move away from hard and fast rules to ensure innovative treatments are made available for people who desperately need them. Until then cost-effectiveness will continue to be put above giving people more time."