A Study of Bevacizumab Added to Trastuzumab Plus Docetaxel in the Neoadjuvant Setting in Participants With Early Stage HER2-Positive Breast Cancer

This randomized study will assess the effect of adding bevacizumab to trastuzumab plus docetaxel in neoadjuvant therapy in participants with early stage human epidermal growth factor receptor 2 (HER2)-positive breast cancer. After 2 cycles of trastuzumab and docetaxel once every 3 weeks, participants with a response (change in standard uptake value \[SUV\]) of less than (\<) 70 percent (%) on Positron Emission Tomography (PET) will be randomized in a 2:1 ratio to receive Cycles 3 to 6 of trastuzumab (6 milligrams per kilogram \[mg/kg\]) and docetaxel (100 milligrams per square meter \[mg/m\^2\]) with or without bevacizumab (15 mg/kg). Participants with a response of greater than or equal to (\>/=) 70% will receive trastuzumab plus docetaxel in Cycles 3 to 6. All participants will receive trastuzumab alone in Cycle 7, and will undergo surgery (as per investigator\'s discretion) after Cycle 7 and between 4 and 6 weeks after the treatment perfusion of Cycle 6. After surgery, all participants will receive a further 11 cycles of trastuzumab plus radiotherapy (starting from 4-8 weeks after surgery during 4-6 weeks, according to site\'s standard practice) with or without hormonal therapy (mandatory if positive hormone receptors). Participants will be followed for up to 5 years from start of neoadjuvant treatment.