Enhertu (Trastuzumab Deruxtecan)

Description

Enhertu (trastuzumab deruxtecan) is an antibody-drug conjugate (ADC) composed of a humanized anti-HER2 IgG1 monoclonal antibody linked to a topoisomerase I inhibitor (deruxtecan) via a cleavable linker. It is indicated for the treatment of adult patients with unresectable or metastatic HER2-positive breast cancer who have received prior anti-HER2–based regimens, as well as for HER2-low breast cancer, HER2-positive gastric cancer, and non–small cell lung cancer (NSCLC) with HER2 mutations. Enhertu delivers its cytotoxic payload directly to HER2-expressing tumor cells, enhancing efficacy while limiting systemic exposure.

Directions

Enhertu is administered via intravenous infusion once every three weeks (21-day cycle). The recommended dose is 5.4 mg/kg for HER2-positive breast cancer and 6.4 mg/kg for gastric or lung cancer, infused over 90 minutes for the first dose, and 30 minutes if well-tolerated in subsequent infusions. Treatment should be continued until disease progression or unacceptable toxicity. Dose modifications may be necessary based on adverse events, particularly pulmonary and hematologic toxicities.

Ingredients

Each Enhertu vial contains:

• Trastuzumab deruxtecan 100 mg (lyophilized powder)

• L-histidine

• L-histidine hydrochloride

• Sucrose

• Polysorbate 80

• Water for injection (for reconstitution)

The reconstituted solution must be diluted with 5% dextrose injection and administered immediately or stored under controlled conditions.

Contraindications

Enhertu is contraindicated in patients with:

• Known serious hypersensitivity to trastuzumab deruxtecan or any excipients

• Severe hypersensitivity reactions or anaphylaxis to prior trastuzumab-based therapy (in select cases)

Cautions

Interstitial lung disease (ILD)/pneumonitis is a potentially life-threatening adverse effect of Enhertu and requires immediate evaluation if new or worsening respiratory symptoms occur. Treatment should be interrupted for suspected ILD and permanently discontinued for Grade 2 or higher confirmed cases. Monitor for left ventricular dysfunction, as with other HER2-targeted agents, and assess LVEF at baseline and periodically during treatment. Enhertu may cause severe neutropenia, thrombocytopenia, or anemia. Embryo-fetal toxicity is a concern; effective contraception is required during treatment and for at least 7 months after the last dose.

Side Effects

Common side effects of Enhertu include:

• Nausea and vomiting

• Fatigue

• Alopecia

• Neutropenia

• Anemia

• Constipation

• Diarrhea

• Decreased appetite

• Cough

• Infusion-related reactions

Serious adverse effects may include:

• Interstitial lung disease/pneumonitis

• Severe neutropenia or febrile neutropenia

• Left ventricular dysfunction

• Hypersensitivity/anaphylaxis

• Embryo-fetal toxicity

Product Code : 14593