From the Research
Phesgo, a combination of pertuzumab, trastuzumab, and hyaluronidase, can typically be continued for up to one year (18 cycles) in the adjuvant setting for early breast cancer, or indefinitely until disease progression or unacceptable toxicity in the metastatic setting. For early HER2-positive breast cancer, patients usually receive Phesgo every three weeks for a total of one year (18 cycles), including any cycles given before surgery (neoadjuvant therapy) 1. In metastatic HER2-positive breast cancer, treatment continues until the disease progresses or side effects become intolerable, with a median overall survival of 56.5 months as seen in the CLEOPATRA trial 2.
Some key points to consider when administering Phesgo include:
- Regular cardiac monitoring is necessary as both pertuzumab and trastuzumab can cause heart dysfunction 2
- Dose adjustments are not typically made, but treatment may be temporarily interrupted if significant side effects occur 3
- The extended duration in metastatic disease reflects the goal of ongoing disease control, while the one-year limit in early breast cancer represents the optimal balance between efficacy and potential cardiac toxicity based on clinical trials 4
- Phesgo has been shown to be cost-efficient and can provide expanded access to treatment for patients with HER2-positive breast cancer 5
It's worth noting that the most recent and highest quality study on this topic is the CLEOPATRA trial, which demonstrated the efficacy and safety of pertuzumab in combination with trastuzumab and docetaxel in patients with HER2-positive metastatic breast cancer 2. However, the specific details of Phesgo administration, including duration of treatment, are not explicitly stated in this study. Therefore, the recommendation to continue Phesgo for up to one year in the adjuvant setting or indefinitely in the metastatic setting is based on a combination of the available evidence and clinical expertise.