One randomised controlled trial (RCT) (n=469) of first-line trastuzumab combination therapy was available. All individuals had HER2 overexpression at least at level 2 or more. Patients who had not previously received anthracyclines were randomised to an anthracycline in combination with cyclophosphamide with or without trastuzumab. Patients who had previously received an anthracycline as adjuvant therapy (n=188) were randomised to paclitaxel (n=96) or paclitaxel plus trastuzumab (n=92). The primary endpoint was time to progression and the median duration of follow-up was 30 (range 30 to 51) months. Patients in all arms of the trial were given the option of receiving trastuzumab monotherapy at the time of disease progression, meaning that allocation to this further treatment was non-random.