This summary table contains detailed information about research studies. Summary tables are a useful way to look at the science behind many breast cancer guidelines and recommendations. However, to get the most out of the tables, it’s important to understand some key concepts. Learn how to read a research table.
Introduction: About 10-20 percent of newly diagnosed breast cancers are HER2-positive [1-2]. This means they have high amounts of a protein called HER2 on the surface of the cancer cells.
The drugs pertuzumab (Perjeta) and trastuzumab (Herceptin) target HER2-positive cancer cells.
Pertuzumab in combination with trastuzumab and chemotherapy (taxane chemotherapy is preferred) can slow the growth of HER2-positive metastatic breast cancer and increase survival better than trastuzumab and chemotherapy alone . The chemotherapy drug doxorubicin (Adriamycin) and other anthracyclines should not be used in this drug combination.
Learn more about pertuzumab (including its side effects) and metastatic breast cancer treatment.
Study selection criteria: Randomized clinical trials with 100 or more participants with HER2-positive metastatic breast cancer.
Study Population(number of participants)
Overall Response Rate—Percent who Responded to Treatment(95% CI)
Overall Survival at One Year
Phase III clinical trials
CLEOPATRA study [4-6]
Pertuzumab and trastuzumab with chemotherapy (docetaxel)
Trastuzumab with chemotherapy (docetaxel)
PHEREXA study 
Pertuzumab and trastuzumab with chemotherapy (capecitabine)
Trastuzumab with chemotherapy (capecitabine)
CI = Confidence interval
NS = The response rate in the pertuzumab plus trastuzumab and chemotherapy group was not statistically significant from the response rate in the trastuzumab and chemotherapy group.* Estimated survival at one year. Estimated 4-year survival was 58% for the pertuzumab + trastuzumab + docetaxel group and 45% for the trastuzumab + docetaxel group. † Estimated survival at 10 months.