Survival data from a study into pertuzumab, trade name Perjeta, found the drug reduced the risk of death by 34% in patients with previously untreated advanced HER2-positive breast cancer, a particularly aggressive form of the disease.
Around 4100 women are diagnosed with breast cancer in Scotland every year. With up to 25% of all breast cancer sufferers HER2-positive, around 1025 will suffer the particular strain in Scotland.
In HER2-positive breast cancer, the HER2 receptor sends a faulty signal to cells, causing rapid growth and spread of the cancerous tumour.
Aberdeen Royal Infirmary, the Western General Hospital, Edinburgh, and the Beatson Cancer Centre in Glasgow were among 15 centres from the UK involved in the international trial.
Dr Peter Canney, from the Beatson Cancer Centre, said: "HER2-positive breast cancer is an aggressive disease that becomes difficult to treat in the advanced stages – so these results are incredibly exciting.
"Perjeta has been shown to bolster the effects of Herceptin by controlling cancer for longer and extending patients' lives. This is great news for patients with HER2-positive breast cancer."
The current gold standard of care involves treatment with trastuzumab (trade name Herceptin), a humanised antibody designed to target and block the function of HER2, and sessions of chemotherapy.