The standard of care for women with HER2-positive metastatic breast cancer is a taxane, pertuzumab, and trastuzumab, Kim Blackwell, MD, explains. This was established by data from the phase III CLEOPATRA trial, which demonstrated a 15.7-month improvement in overall survival with the addition of pertuzumab to trastuzumab and a taxane compared with a taxane and trastuzumab alone for patients with HER2-positive metastatic breast cancer (median 56.5 vs 40.8 months). The survival advantage seen in this study was the largest recorded in an active comparator study for any solid tumor, notes Blackwell.

In many situations, the taxane utilized with the two antibodies does not seem to impact outcomes, notes Lee Schwartzberg, MD. In Europe, docetaxel is preferred, while weekly paclitaxel is favored in parts of the United States. In her practice, Ruth O’Regan, MD, uses 6 weeks of docetaxel, given on a 3-week schedule, suggesting the versatility of the treatment strategy.

A new challenge facing clinicians is the optimal reinitiating of therapy in patients who have progressed after extended disease-free intervals on the pertuzumab regimen. Richard Finn, MD, states that he does not find it unreasonable to go back to docetaxel or the previously used taxane in this situtation. In contrast, Blackwell comments that she would likely switch to T-DM1 for patients who have progressed.