Phesgo

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, subdomains II and IV, respectively, 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. Additionally, the Fc portion of both their IgG1 framework provides for potent activation of antibody-dependent cell-mediated cytotoxicity (ADCC). In vitro, both pertuzumab and trastuzumab ADCC are exerted preferentially on HER2-overexpressing cancer cells compared with cancer cells that do not overexpress HER2.

Patient Selection: Patients treated with Phesgo should have HER2-positive tumor status, defined as a score of 3+ by immunohistochemistry (IHC) or a ratio of ≥ 2.0 by in situhybridization (ISH), assessed by a validated test. To ensure accurate and reproducible results, the testing must be performed in a specialized laboratory, which can ensure validation of the testing procedures.

Administration of Phesgo: Phesgo therapy should only be administered under the supervision of a healthcare professional experienced in the treatment of cancer patients. Substitution by any other biological medicinal product requires the consent of the prescribing physician. Patients currently receiving intravenous pertuzumab and trastuzumab can switch to Phesgo. Switching treatment from intravenous pertuzumab and trastuzumab to Phesgo (or vice versa) was investigated in study MO40628. In order to prevent medication errors, it is important to check the vial labels to ensure that the drug being prepared and administered is Phesgo. Phesgo is for subcutaneous (SC) use in the thigh only. Do not administer intravenously.

Metastatic and Early Breast Cancer-

• Loading dose: 1200 mg pertuzumab / 600 mg trastuzumab
• Maintenance dose (every 3 weeks): 600 mg pertuzumab / 600 mg trastuzumab

Early Breast Cancer (EBC): In the neoadjuvant setting (before surgery), it is recommended that patients are treated with Phesgo for three to six cycles depending on the regimen chosen in combination with chemotherapy. In the adjuvant setting (after surgery), Phesgo should be administered for a total of one year (maximum 18 cycles or until disease recurrence, or unmanageable toxicity, whichever occurs first), as part of a complete regimen for early breast cancer, including standard anthracycline- and/or taxane-based chemotherapy. Phesgo treatment should start on Day 1 of the first taxane-containing cycle and should continue even if chemotherapy is discontinued. Patients who start Phesgo in the neoadjuvant setting should continue to receive adjuvant Phesgo to complete 1 year of treatment (maximum 18 cycles).

Metastatic Breast Cancer (MBC): Phesgo should be administered in combination with docetaxel until disease progression or unmanageable toxicity. Treatment with Phesgo may continue even if treatment with docetaxel is discontinued.

Phesgo is contraindicated in patients with a known hypersensitivity to pertuzumab, trastuzumab or any of the excipients

Phesgo should be avoided during pregnancy unless the potential benefit for the mother outweighs the potential risk to the fetus. As human IgG is excreted in human milk, and the potential for absorption and harm to the infant is unknown, women should be advised to discontinue nursing during Phesgo therapy and for 7 months
after the last dose of Phesgo.

Pediatric use: The safety and efficacy of Phesgo in children and adolescents (<18 years) has not been established.

Geriatric use: No dose adjustment of Phesgo is required in patients ≥65 years of age 

Renal Impairment: Dose adjustments of Phesgo are not needed in patients with mild or moderate renal impairment. No dose recommendations can be made for patients with severe renal impairment because of the limited pharmacokinetic data available.

Hepatic Impairment: The safety and efficacy of Phesgo have not been studied in patients with hepatic impairment. No dose recommendation can be made for Phesg.

Store at 2°C-8°C. Keep vial in the outer carton in order to protect from light. Do not freeze.