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Last Updated: 11/14/23

Information below provided by the Pharmaceutical Company.

Pertuzumab/trastuzumab/hyaluronidase-zzxf (PHESGO®)

Agent Description

Ready-to-use formulation containing fixed-dose combination (FDC) of pertuzumab and trastuzumab with recombinant human hyaluronidase (rHuPH20) for subcutaneous (SC) administration (hereinafter referred to as “PH FDC SC” or “PHESGO”). The active ingredients (monoclonal antibodies: pertuzumab and trastuzumab) in PH FDC SC are identical to the active ingredients in the approved Perjeta® (pertuzumab intravenous [IV]) and Herceptin® (trastuzumab IV or SC) formulations. PH FDC SC has been developed to offer patients a less invasive and faster administration of pertuzumab and trastuzumab compared to IV infusions.

Mechanism of Action

Pertuzumab and trastuzumab are recombinant humanized immunoglobulin (Ig) G1κ monoclonal antibodies, which target the human epidermal growth factor receptor 2 (HER2, also known as c-erbB-2), a transmembrane glycoprotein with intrinsic tyrosine kinase activity. Pertuzumab and trastuzumab bind to distinct HER2 epitopes without competing and have complementary mechanisms for disrupting HER2 signaling. This results in augmented anti-proliferative activity in vitro and in vivo when pertuzumab and trastuzumab are given in combination.


Fully human immunoglobulin monoclonal antibodies that are produced in Chinese hamster ovary cells.

Molecular Targets

Human epidermal growth factor receptor 2 (HER2, also known as c-erbB-2)


The product PH FDC SC contains pertuzumab and trastuzumab (co-formulated with rHuPH20) in one FDC for SC injection (PH FDC SC) has been developed for the treatment of HER2-positive breast cancer. PH FDC SC is to be administered subcutaneously in the thigh with a shorter administration time (approximately over 5 to 8 minutes) compared to Perjeta® and Herceptin® IV formulations, and with non-body-weight dependent dosing. It is expected that SC administration of PH FDC SC will result in an in a less invasive and faster administration of pertuzumab and trastuzumab, while maintaining similar efficacy and safety to the Perjeta® and Herceptin® IV formulations.

Package insert:

Studies of Interest

In general, study proposals listed below will NOT be supported:

  • Combinations with ado-trastuzumab emtansine
  • Combinations with bevacizumab
  • Combinations with biosimilar Trastuzumab
  • Novel combinations in the absence of Phase I data
  • Studies that are answering another company’s development or medical questions where pertuzumab plus trastuzumab is already standard of care.

Information collaborator would like included in investigator proposals

Sponsor-investigator must indicate appropriate facilities/personnel, experience treating patients in desired research population and that they have an adequate sample size they can enroll into study, and a proven track record for conducting and publishing research. Formulary LOI proposal needs to describe if they have ongoing studies at their institution that would compete with the research population of interest during the expected patient accrual window.