Phesgo is a fixed-dose combination of Perjeta (pertuzumab) and Herceptin (trastuzumab) (TRASTUZUMAB) with hyaluronidase, administered by subcutaneous (SC; under the skin) injection in combination with intravenous (IV) chemotherapy, for the treatment of early and metastatic HER2-positive breast cancer. This is the first time that Roche has combined two monoclonal antibodies that can be administered by a single SC injection.
The mechanisms of action of Perjeta and Herceptin are believed to complement each other, as both bind to the HER2 receptor, but to different locations. The combination of Perjeta and Herceptin is thought to provide a more comprehensive, dual blockade of HER signalling pathways, thus preventing tumour cell growth and survival. The hyaluronidase in Phesgo temporarily and reversibly degrades hyaluronan, a gel-like substance that forms a barrier between cells under the skin, enabling Phesgo to be rapidly dispersed and absorbed over a greater area.
Phesgo offers faster administration of Perjeta and Herceptin under the skin in just minutes, compared to hours with standard IV administration. Phesgo can be administered by a healthcare professional in a treatment centre or at a patient’s home.
Dose Modification For delayed Or Missed Doses
For delayed or missed doses of PHESGO, if the time between two sequential injections is less than 6 weeks, administer the maintenance dose of 600 mg, 600 mg, and 20,000 units/10 mL. Do not wait until the next planned dose.
If the time between two sequential injections is 6 weeks or more, re-administer the initial dose of 1,200 mg, 600 mg, and 30,000 units/15 mL, followed every 3 weeks thereafter by a maintenance dose of 600 mg, 600 mg, and 20,000 units/10 mL.