Home Drug Guide Pertuzumab, Trastuzumab, Hyaluronidase-zzxf (Phesgo)

Drug Guide

Generic Name

Pertuzumab, Trastuzumab, Hyaluronidase-zzxf (Phesgo)

Brand Names Phesgo

Classification

Therapeutic: Antineoplastic agent (HER2-positive breast cancer)

Pharmacological: Monoclonal antibody (pertuzumab and trastuzumab), Enzymes (hyaluronidase)

FDA Approved Indications

Neoadjuvant and adjuvant treatment of HER2-positive breast cancer

Mechanism of Action

Pertuzumab and trastuzumab are monoclonal antibodies that target the HER2 receptor, inhibiting cell proliferation. Hyaluronidase facilitates the dispersion and absorption of subcutaneously administered drugs by degrading hyaluronic acid in the extracellular matrix.

Dosage and Administration

Adult: Administer under supervision, typically as an IV infusion with premedication to reduce infusion reactions.

Pediatric: Not established for pediatric use.

Geriatric: Start at lower doses; monitor closely for adverse effects.

Renal Impairment: No specific adjustment required.

Hepatic Impairment: No specific adjustment required.

Pharmacokinetics

Absorption: Rapid absorption after subcutaneous injection for hyaluronidase; monoclonal antibodies administered intravenously.

Distribution: Distributed mainly in plasma and extracellular fluid.

Metabolism: Metabolized via reticuloendothelial system, typical of monoclonal antibodies.

Excretion: Excreted through catabolism into amino acids.

Half Life: Approximately 18-25 days for trastuzumab; similar for pertuzumab.

Contraindications

Hypersensitivity to any component.
History of serious hypersensitivity reactions.

Precautions

Monitor for infusion-related reactions, cardiotoxicity, and hypersensitivity. Use with caution in patients with cardiac impairment, and ensure baseline cardiac function is assessed.

Adverse Reactions - Common

Infusion reactions (Common)
Neutropenia (Common)
Diarrhea (Common)
Nausea and vomiting (Common)

Adverse Reactions - Serious

Left ventricular dysfunction / Heart failure (Less common)
Infusion-related reactions leading to serious events (Less common)
Pulmonary toxicity (Rare)

Drug-Drug Interactions

Other cardiotoxic agents, such as anthracyclines.
Potential interactions with immunosuppressants.

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor cardiac function (LVEF), signs of infusion reactions, and allergic reactions.

Diagnoses:

Risk for cardiotoxicity
Risk for infusion reactions

Implementation: Administer as prescribed with premedication (antihistamines, corticosteroids). Monitor during and after infusion.

Evaluation: Assess for adverse effects, infusion tolerance, and cardiac function.

Patient/Family Teaching

Report symptoms of infusion reactions such as chills, rash, or difficulty breathing.
Avoid pregnancy during therapy and for some months after.
Understand the importance of regular cardiac monitoring.

Special Considerations

Black Box Warnings:

Cardiotoxicity, including heart failure and left ventricular dysfunction.
Infusion reactions.

Genetic Factors: Not specific to genetic factors.

Lab Test Interference: May affect assessments of cardiac function.

Overdose Management

Signs/Symptoms: Allergic reactions, hypotension, or other infusion-related reactions.

Treatment: Supportive care, symptomatic treatment, and discontinuation of infusion.

Storage and Handling

Storage: Store vials refrigerated between 2°C and 8°C. Protect from light.

Stability: Refer to manufacturer’s guidelines for beyond-use dates.