Pertuzumab

What it is and how it works

Mechanism of Action Pertuzumab targets the extracellular dimerization domain (Subdomain II) of the human epidermal growth factor receptor 2 protein (HER2) and, thereby, blocks ligand-dependent heterodimerization of HER2 with other HER family members, including EGFR, HER3, and HER4. As a result, pertuzumab inhibits ligand-initiated intracellular signaling through two major signal pathways, mitogen-activated protein (MAP) kinase, and phosphoinositide 3-kinase (PI3K). Inhibition of these signaling pathways can result in cell growth arrest and apoptosis, respectively. In addition, pertuzumab mediates antibody-dependent cell-mediated cytotoxicity (ADCC).

Mechanism class: HER2/Neu/cerbB2 Antagonists

Indications

is a HER2/neu receptor antagonist indicated for: Use in combination with trastuzumab and docetaxel for treatment of adults with HER2-positive metastatic breast cancer (MBC) who have not received prior anti-HER2 therapy or chemotherapy for metastatic disease. Use in combination with trastuzumab and chemotherapy as neoadjuvant treatment of adults with HER2-positive, locally advanced, inflammatory, or early stage breast cancer (either greater than 2 cm in diameter or node positive) as part of a complete treatment regimen for early breast cancer. ( 1.2 , 2.2 , 14.2 ) adjuvant treatment of adults with HER2-positive early breast cancer at high risk of recurrence ( 1.2 , 2.2 , 14.3 ) Metastatic Breast Cancer (MBC) PERJETA is indicated for use in combination with trastuzumab and docetaxel for the treatment of adults with HER2-positive metastatic breast cancer who have not received prior anti-HER2 therapy or chemotherapy for metastatic disease .

Dosage and administration (summary)

For intravenous infusion only. Do not administer as an intravenous push or bolus. HER2 testing: Perform using FDA-approved tests by laboratories with demonstrated proficiency. The initial PERJETA dose is 840 mg administered as a 60-minute intravenous infusion, followed every 3 weeks thereafter by 420 mg administered as a 30 to 60 minute intravenous infusion. MBC: Administer PERJETA, trastuzumab or trastuzumab hyaluronidase-oysk, and docetaxel every 3 weeks. Neoadjuvant: Administer PERJETA, trastuzumab or trastuzumab hyaluronidase-oysk, and chemotherapy preoperatively every 3 weeks for 3 to 6 cycles.

Contraindications

is contraindicated in patients with known hypersensitivity to pertuzumab or to any of its excipients . PERJETA is contraindicated in patients with known hypersensitivity to pertuzumab or to any of its excipients.

Warnings and precautions

Infusion-Related Reactions: PERJETA can cause serious infusion reactions, including fatal events: Monitor for signs and symptoms. If a significant infusion-associated reaction occurs, slow or interrupt the infusion and administer appropriate medical therapies. Hypersensitivity Reactions/Anaphylaxis: PERJETA can cause hypersensitivity reactions, including anaphylaxis: Monitor for signs and symptoms, including angioedema. If a severe hypersensitivity reaction/anaphylaxis occurs, discontinue the infusion immediately and administer appropriate medical therapies.

Pregnancy

Pregnancy If PERJETA is administered during pregnancy, or if a patient becomes pregnant while receiving PERJETA or within 7 months following the last dose of PERJETA in combination with trastuzumab, health care providers and patients should immediately report PERJETA exposure to Genentech at 1-888-835-2555.

Storage and supply

Storage and Handling Store vials refrigerated at 2°C to 8°C (36°F to 46°F) in the original carton until time of use to protect from light. Do not freeze. Do not shake. DO NOT FREEZE. DO NOT SHAKE.

Source: Pertuzumab (Perjeta) — US FDA prescribing information, 2026-04-30, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.