Pertuzumab, commonly known as Perjeta, is an antibody drug that targets HER2-positive cancer cells, but in a different way than trastuzumab.

Pertuzumab is always given in combination with trastuzumab, and not by itself. This combination is given through an IV into a vein or by injection under the skin every 3 weeks for one year.

Treatment with pertuzumab and trastuzumab may begin before or after breast cancer surgery.

Possible side effects of pertuzumab include diarrhea, nausea, fatigue and rash. Since pertuzumab is always given with trastuzumab, which can cause heart problems, your heart will be checked before and during treatment.

For more information, visit the HER2-Targeted Therapies page within the Treatment section of komen.org.

Pertuzumab is also used to treat HER2-positive metastatic breast cancer. For more information, see the Living with Metastatic Breast Cancer chapter of this tool.