From the Research
Phesgo is typically given once every three weeks (21 days) as a subcutaneous injection. The initial loading dose is larger and takes about 8 minutes to administer, while subsequent maintenance doses are smaller and take approximately 5 minutes to inject 1. The total duration of Phesgo treatment is usually 18 cycles (about one year) for early breast cancer, though this may vary based on individual treatment plans. For metastatic breast cancer, Phesgo may be continued indefinitely as long as the patient is benefiting from treatment and not experiencing unacceptable side effects. Phesgo combines two targeted therapies (pertuzumab and trastuzumab) with hyaluronidase to treat HER2-positive breast cancer. This fixed-dose combination allows for quicker administration compared to traditional intravenous infusions of the same medications, which can take hours. Some key points to consider when administering Phesgo include:
- The fixed-dose combination of pertuzumab and trastuzumab for subcutaneous injection was non-inferior to IV pertuzumab plus trastuzumab in terms of pertuzumab and trastuzumab serum levels in the phase III FeDeriCa study 2.
- The most common grade 3-4 adverse events occurring during neoadjuvant treatment with HER2-targeted therapy plus chemotherapy in 5% or more of patients were neutropenia, decreased neutrophil count, febrile neutropenia, diarrhoea, and decreased white blood cell count 2.
- Patients should maintain regular follow-up appointments with their oncologist to monitor treatment response and manage any potential side effects throughout the course of therapy. It is also worth noting that the administration of Phesgo can be done at home by nurse providers in patients receiving maintenance HER2-targeted therapy every 3 weeks, as shown in a US multicenter expanded access study (NCT04395508) 1.