Herceptin (trastuzumab)
HERCEPTIN (trastuzumab) – an HER2/neu receptor antagonist commonly used to treat certain cancers. The HER2 (or c-erbB2) proto-oncogene encodes a transmembrane receptor protein of 185 kDa, which is structurally related to the epidermal growth factor receptor. Herceptin has been shown, in both in vitro assays and in animals, to inhibit the proliferation of human tumor cells that overexpress HER2.
FDA approved uses: Herceptin is indicated for the treatment of: HER2-overexpressing breast cancer; HER2-overexpressing metastatic gastric or HER2-overexpressing gastroesophageal junction adenocarcinoma.
Available dosage forms: Multidose vial nominally containing 440 mg Herceptin as a lyophilized, sterile powder.
Usual dosage: For intravenous (IV) infusion only. Do not administer as an IV push or bolus. Adjuvant Treatment of HER2-Overexpressing Breast Cancer – Administer at either: Initial dose of 4 mg/kg over 90 minute IV infusion, then 2 mg/kg over 30 minute IV infusion weekly for 52 weeks, or Initial dose of 8 mg/kg over 90 minutes IV infusion, then 6 mg/kg over 30−90 minutes IV infusion every three weeks for 52 weeks. Metastatic HER2-Overexpressing Breast Cancer – Initial dose of 4 mg/kg as a 90 minute IV infusion followed by subsequent weekly doses of 2 mg/kg as 30 minute IV infusions. Metastatic HER2-overexpressing Gastric Cancer. Initial dose of 8 mg/kg over 90 minutes IV infusion, followed by 6 mg/kg over 30 to 90 minutes IV infusion every 3 weeks.
Contraindications: The manufacturer states that there are no contraindications to the product.
Special warnings: Cardiomyopathy – Herceptin can result in sub-clinical and clinical cardiac failure manifesting as CHF, and decreased LVEF, with greatest risk when administered concurrently with anthracyclines. Evaluate cardiac function prior to and during treatment. Discontinue Herceptin for cardiomyopathy. Infusion reactions, Pulmonary toxicity – Discontinue Herceptin for anaphylaxis, angioedema, interstitial pneumonitis, or acute respiratory distress syndrome. Embryo-Fetal Toxicity – Exposure to Herceptin during pregnancy can result in oligohydramnios, in some cases complicated by pulmonary hypoplasia and neonatal death.
Adverse reactions (side effects) of these medications: The most common side effects of Herceptin varied by the condition being treated. In adjuvant breast cancer treatment, side effects included headache, diarrhea, nausea, and chills. In metastatic breast cancer the most common adverse reactions (> 10%) are fever, chills, headache, infection, congestive heart failure, insomnia, cough, and rash. In metastatic gastric cancer the most common adverse reactions ( ≥10%) are neutropenia, diarrhea, fatigue, anemia, stomatitis, weight loss, upper respiratory tract infections, fever, thrombocytopenia, mucosal inflammation, nasopharyngitis, and dysgeusia.
Common drug interactions: In one study, the mean serum trough concentration of trastuzumab was consistently elevated approximately 1.5-fold, when administered in combination with paclitaxel as compared to trough concentrations of trastuzumab when administered in combination with an anthracycline and cyclophosphamide.
Special instructions for patients: The manufacturer recommends that patents should be advised of the following:
Advise patients to contact a health care professional immediately for any of the following: new onset or worsening shortness of breath, cough, swelling of the ankles/legs, swelling of the face, palpitations, weight gain of more than 5 pounds in 24 hours, dizziness or loss of consciousness.
Advise pregnant women and women of childbearing potential that Herceptin exposure can result in fetal harm.
Advise women of childbearing potential to use effective contraceptive methods during treatment and for a minimum of six months following Herceptin.
Advise nursing mothers treated with Herceptin to discontinue nursing or discontinue Herceptin, taking into account the importance of the drug to the mother.
Encourage women who are exposed to Herceptin during pregnancy to enroll in MotHER- the Herceptin Pregnancy Registry (1-800-690-6720).
Full prescribing information may be found at the manufacturer‘s official website Herceptin.com or at the U.S. Food and Drug Administration’s website at Herceptin Info at Drugs@FDA
Tags: Herceptin, Herceptin adverse events, Herceptin adverse reactions, Herceptin dose, what are the side effects of Herceptin