FDA Approves Ontruzant (trastuzumab-dttb) for HER2-Overexpressing Breast and Gastric Cancers
The FDA approved Ontruzant (trastuzumab-dttb) on January 18, 2019, for the treatment of HER2-overexpressing cancers in adults, including breast cancer and metastatic gastric or gastroesophageal junction adenocarcinoma. This approval provides a biosimilar option to trastuzumab, expanding access to targeted therapy for patients with these aggressive malignancies. Clinically, Ontruzant is indicated for adjuvant treatment of HER2-overexpressing breast cancer as part of multi-agent regimens or as a single agent, and for metastatic breast cancer in combination with paclitaxel or as monotherapy after prior chemotherapy. For metastatic gastric cancer, it is used with cisplatin and capecitabine or 5-fluorouracil in treatment-naive patients. The approval underscores the importance of HER2 testing via FDA-approved companion diagnostics to identify eligible patients, as improper assay performance can lead to unreliable results. Ontruzant is administered intravenously with specific dosing schedules, and it should not be substituted for other trastuzumab-based products like ado-trastuzumab emtansine or fam-trastuzumab deruxtecan. Key safety considerations include monitoring left ventricular ejection fraction (LVEF) due to cardiotoxicity risks and verifying pregnancy status in females of reproductive potential. This approval offers clinicians an additional tool in managing HER2-driven cancers, with dosing tailored to the cancer type and treatment setting.
＋ Clinical Details (Mechanism · Dosing · Trial Data · Warnings)
Not reported in label.
Ontruzant is indicated in adults for: adjuvant treatment of HER2-overexpressing node positive or node negative breast cancer (ER/PR negative or with one high risk feature) as part of treatment regimens with doxorubicin, cyclophosphamide, and paclitaxel or docetaxel, or with docetaxel and carboplatin, or as a single agent after anthracycline-based therapy; metastatic breast cancer in combination with paclitaxel for first-line treatment or as a single agent after one or more chemotherapy regimens; and metastatic gastric or gastroesophageal junction adenocarcinoma in combination with cisplatin and capecitabine or 5-fluorouracil for patients without prior metastatic treatment. Patients must be selected based on HER2 protein overexpression or gene amplification using FDA-approved companion diagnostics specific to breast or gastric cancers.
Ontruzant is for intravenous infusion only, not as IV push or bolus, and has different instructions than subcutaneous trastuzumab products. Do not mix with other drugs or substitute for ado-trastuzumab emtansine or fam-trastuzumab deruxtecan. For adjuvant breast cancer: initial dose of 4 mg/kg 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 over 30-90 minutes every three weeks to complete 52 weeks; or initial dose of 8 mg/kg over 90 minutes, then 6 mg/kg over 30-90 minutes every three weeks for 52 weeks. For metastatic breast cancer: initial dose of 4 mg/kg over 90 minutes, then 2 mg/kg over 30 minutes weekly. For metastatic gastric cancer: initial dose of 8 mg/kg over 90 minutes, then 6 mg/kg over 30-90 minutes every three weeks.
trial data not available in label
Assess left ventricular ejection fraction (LVEF) before initiation and regularly during treatment. Verify pregnancy status in females of reproductive potential before initiation. Improper HER2 assay performance can lead to unreliable results.
Not reported in label.
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