A Multicenter Randomized Phase III Study to Compare the Combination Trastuzumab and Capecitabine, With or Without Pertuzumab, in Patients With HER2-Positive Metastatic Breast Cancer That Have Progressed After One Line of Trastuzumab-Based Therapy in the Metastatic Setting (PHEREXA)

This randomized, two-arm study evaluated the efficacy and safety of a combination of
trastuzumab and capecitabine with or without pertuzumab in patients with human epidermal
growth factor receptor 2 (HER2)-positive metastatic breast cancer. The study population
consisted of female patients, whose disease had progressed during or following previous
trastuzumab therapy for metastatic disease. All patients in Arm A and Arm B received
trastuzumab (8 mg/kg iv as loading dose and then 6 mg/kg iv every 3 weeks thereafter) and
capecitabine oral twice daily for 14 days every 3 weeks (1250 mg/m2 twice daily in Arm A and
1000 mg/m2 twice daily in Arm B). In addition, patients in Arm B received pertuzumab (840 mg
iv as loading dose and then 420 mg iv thereafter) every 3 weeks. Study treatment continued
until disease progression or unacceptable toxicity.