Pertuzumab/trastuzumab/hyaluronidase, sold under the brand name Phesgo, is a fixed-dose combination medication to treat adults with HER2-positive breast cancer that has spread to other parts of the body, and for treatment of adults with early HER2-positive breast cancer. It contains pertuzumab, trastuzumab, and hyaluronidase–zzxf. It is injected under the skin via subcutaneous injection in the thigh. In the European Union, Phesgo contains the active ingredients pertuzumab and trastuzumab along with the enzyme vorhyaluronidase alfa.The most common side effects include alopecia (hair loss), nausea, diarrhea, anemia (reduced number of red blood cells) and asthenia (lack of energy). It can cause worsening of chemotherapy induced neutropenia (low level of white blood cells). It may cause harm to a developing fetus or a newborn baby.HER2-positive breast cancer, which makes up approximately one-fifth of breast cancers, has too much of a protein called human epidermal growth factor receptor 2 (HER2), which promotes the growth of cancer cells. Pertuzumab and trastuzumab bind to sites on HER2 and disrupt signaling to stop cancer cell growth.
Clinical trial number NCT03493854 for "A Study to Evaluate the Pharmacokinetics, Efficacy, and Safety of Subcutaneous Administration of the Fixed-Dose Combination of Pertuzumab and Trastuzumab in Combination With Chemotherapy in Participants With HER2-Positive Early Breast Cancer (FeDeriCa)" at ClinicalTrials.gov