Ontruzant (Trastuzumab-Dttb) for Breast Cancer

Overview
Ontruzant is approved by the U.S. Food and Drug Administration (FDA) for HER2-overexpressing breast cancer. Ontruzant is prescribed for both early-stage and metastatic HER2-positive breast cancer. Individuals are typically selected for treatment based on positive HER2 test results from an FDA-approved diagnostic test. Ontruzant is a biosimilar to Herceptin (trastuzumab), meaning it has been shown to have no clinically meaningful differences in safety and effectiveness from the biologic Herceptin. Ontruzant is also known by its drug name, trastuzumab-dttb.

Ontruzant is a biologic that works as a HER2/neu receptor antagonist. It targets the HER2 protein, which is overexpressed in some breast cancer cells, and blocks the growth and survival of these cancer cells. This mechanism helps to manage breast cancer by inhibiting tumor growth and progression.

How do I take it?
Prescribing information states that Ontruzant is administered as an intravenous (IV) infusion for HER2-positive breast cancer. The dosage depends on the specific treatment regimen. 

For early-start breast cancer, an initial dose is given over 90 minutes, followed by weekly doses administered over 30 minutes for 12 to 18 weeks, depending on combination with paclitaxel, docetaxel, or carboplatin. After the initial weekly regimen, the drug is generally administered every three weeks to complete 52 weeks of therapy. Alternatively, an initial dose can be given over 90 minutes, followed by doses every three weeks for 52 weeks.

For metastatic breast cancer, an Initial dose is given as a 90-minute IV infusion, followed by weekly doses over 30 minutes.

Ontruzant should be administered exactly as prescribed by a healthcare provider. 

Side effects
Common side effects of Ontruzant for treating adjuvant breast cancer include headache, diarrhea, and nausea. For treating metastatic breast cancer, other common side effects include chills, fever, infection, congestive heart failure, insomnia, cough, and rash. 

Rare but serious side effects may include cardiomyopathy (heart muscle disease), infusion reactions, pulmonary toxicity (lung damage), embryo-fetal toxicity (harm to a developing embryo, fetus, or unborn infant), and worsening of chemotherapy-induced neutropenia (low white blood cell count). Individuals taking this medication should be monitored closely for any signs of cardiac dysfunction or severe allergic reactions. 

For more information about this treatment, visit:

Label: Ontruzant — Trastuzumab Injection, Powder, Lyophilized, for Solution — DailyMed

Ontruzant — Drugs.com