FDA Approves Herceptin (trastuzumab) for HER2-Overexpressing Breast and Gastric Cancers

Photo by Reproductive Health Supplies Coalition / Unsplash

FDA Published May 22, 2026 Medically reviewed May 22, 2026 DOI ↗ By Dr. Julia Lee, PhD · Oncology, Genomics & Drug Development

Key Takeaway

Consider Herceptin for HER2-overexpressing breast and gastric cancers, with patient selection via FDA-approved companion diagnostic.

The FDA has approved Herceptin (trastuzumab), a HER2/neu receptor antagonist, for the treatment of HER2-overexpressing breast cancer and HER2-overexpressing metastatic gastric or gastroesophageal junction adenocarcinoma. The approval covers adjuvant treatment of HER2-overexpressing node-positive or node-negative breast cancer as part of a regimen with doxorubicin, cyclophosphamide, and either paclitaxel or docetaxel, or with docetaxel and carboplatin, or as a single agent following anthracycline-based therapy. For metastatic breast cancer, Herceptin is indicated in combination with paclitaxel for first-line treatment or as a single agent after one or more prior chemotherapy regimens. In metastatic gastric cancer, it is indicated in combination with cisplatin and capecitabine or 5-fluorouracil for patients who have not received prior treatment for metastatic disease. Patient selection is based on HER2 overexpression or gene amplification using FDA-approved tests. The approval provides a targeted therapy option for these HER2-positive cancers.

＋ Clinical Details (Mechanism · Dosing · Trial Data · Warnings)

Mechanism of Action

Herceptin is a HER2/neu receptor antagonist.

Indication & Patient Population

Herceptin is indicated in adults for the treatment of HER2-overexpressing breast cancer (adjuvant and metastatic) and HER2-overexpressing metastatic gastric or gastroesophageal junction adenocarcinoma. Patient selection is based on HER2 protein overexpression or gene amplification using FDA-approved companion diagnostics.

Dosing & Administration

For intravenous infusion only. Do not administer as IV push or bolus. Adjuvant breast cancer: either 4 mg/kg initial dose over 90 minutes then 2 mg/kg over 30 minutes weekly for 12 weeks (with paclitaxel or docetaxel) or 18 weeks (with docetaxel and carboplatin), followed by 6 mg/kg every 3 weeks for a total of 52 weeks; or 8 mg/kg initial dose then 6 mg/kg every 3 weeks for 52 weeks. Metastatic breast cancer: 4 mg/kg initial dose over 90 minutes then 2 mg/kg weekly over 30 minutes. Metastatic gastric cancer: 8 mg/kg initial dose over 90 minutes then 6 mg/kg every 3 weeks over 30 to 90 minutes. Assess LVEF before and during treatment. Verify pregnancy status before initiation.

Key Clinical Trial Data

Trial data not available in label.

Warnings & Contraindications

Assess left ventricular ejection fraction (LVEF) prior to initiation and at regular intervals during treatment. Verify pregnancy status of females of reproductive potential prior to initiation. Do not substitute Herceptin for or with ado-trastuzumab emtansine or fam-trastuzumab deruxtecan.

Place in Therapy

Herceptin is a targeted therapy for HER2-overexpressing breast and gastric cancers, used in combination with chemotherapy or as a single agent in specific settings.

Study Details

Study typeFda approval

PublishedSep 1998

View Original Abstract ↓

1 INDICATIONS AND USAGE Herceptin is a HER2/neu receptor antagonist indicated in adults for: The treatment of HER2-overexpressing breast cancer. ( 1.1 , 1.2 ) The treatment of HER2-overexpressing metastatic gastric or gastroesophageal junction adenocarcinoma. ( 1.3 ) Select patients for therapy based on an FDA-approved companion diagnostic for Herceptin ( 1 , 2.2 ). 1.1 Adjuvant Breast Cancer Herceptin is indicated in adults for adjuvant treatment of HER2 overexpressing node positive or node negative (ER/PR negative or with one high risk feature [see Clinical Studies (14.1) ] ) breast cancer as part of a treatment regimen consisting of doxorubicin, cyclophosphamide, and either paclitaxel or docetaxel as part of a treatment regimen with docetaxel and carboplatin as a single agent following multi-modality anthracycline based therapy. Select patients for therapy based on an FDA-approved companion diagnostic for Herceptin [see Dosage and Administration (2.2) ] . 1.2 Metastatic Breast Cancer Herceptin is indicated in adults: In combination with paclitaxel for first-line treatment of HER2-overexpressing metastatic breast cancer As a single agent for treatment of HER2-overexpressing breast cancer in patients who have received one or more chemotherapy regimens for metastatic disease. Select patients for therapy based on an FDA-approved companion diagnostic for Herceptin [see Dosage and Administration (2.2) ] . 1.3 Metastatic Gastric Cancer Herceptin is indicated in adults, in combination with cisplatin and capecitabine or 5-fluorouracil, for the treatment of patients with HER2-overexpressing metastatic gastric or gastroesophageal junction adenocarcinoma who have not received prior treatment for metastatic disease. Select patients for therapy based on an FDA-approved companion diagnostic for Herceptin [see Dosage and Administration (2.2) ] .