What is the administration frequency of Phesgo (pertuzumab and trastuzumab)

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Last updated: March 25, 2025View editorial policy

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From the Research

Phesgo is typically administered once every three weeks (21 days) as a subcutaneous injection. The administration frequency of Phesgo, a fixed-dose combination of pertuzumab and trastuzumab, is based on the results of several clinical trials, including the FeDeriCa study 1, which demonstrated non-inferiority of the subcutaneous formulation compared to intravenous pertuzumab plus trastuzumab in patients with HER2-positive early breast cancer.

Key Points

  • The initial loading dose takes about 8 minutes to administer, while subsequent maintenance doses take approximately 5 minutes.
  • The complete treatment course with Phesgo usually lasts for one year (18 cycles) for early breast cancer patients, though this may vary based on individual treatment plans.
  • For metastatic breast cancer, treatment may continue until disease progression or unmanageable toxicity occurs.
  • Phesgo combines pertuzumab, trastuzumab, and hyaluronidase in a single injection, targeting HER2-positive breast cancer by blocking the HER2 protein that promotes cancer cell growth.
  • This fixed-dose combination offers the advantage of shorter administration time compared to traditional intravenous infusions of the same medications.
  • Patients should be monitored for potential side effects, including cardiac dysfunction, as these medications can affect heart function.
  • Regular cardiac assessments are typically performed throughout treatment, as supported by studies such as the phase II trial of pertuzumab and trastuzumab in patients with HER2-positive metastatic breast cancer 2.
  • The development of a subcutaneous fixed-dose combination of pertuzumab and trastuzumab has been reported in studies such as the phase Ib dose-finding study 3, which aimed to identify an SC pertuzumab dose given with recombinant human hyaluronidase that results in comparable exposure to that of the intravenous pertuzumab dose.
  • The most recent study, published in 2024, provides an overview of the pharmacological properties and clinical development of PHESGO, a fixed-dose combination of pertuzumab, trastuzumab, and vorhyaluronidase alfa for subcutaneous injection 4.

Administration Details

  • The administration of Phesgo is typically performed by a healthcare professional.
  • Patients should be monitored for signs of injection site reactions, such as redness, swelling, or pain.
  • The treatment course with Phesgo may be adjusted based on individual patient response and tolerability.
  • As reported in the study published in 2021, the fixed-dose combination of pertuzumab and trastuzumab for subcutaneous injection can be administered in approximately 5-8 minutes 5.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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