Herceptin (trastuzumab)
Genentech / Roche; biosimilars available · HER2-Targeted Monoclonal Antibody
What is Herceptin? Herceptin (trastuzumab) is a HER2-targeted monoclonal antibody by Genentech/Roche, foundational in the treatment of HER2-positive breast cancer and HER2-positive gastric/gastroesophageal junction adenocarcinoma. Multiple biosimilars are FDA-approved.
About Herceptin
| Brand Name | Herceptin |
| Generic / INN | trastuzumab |
| Drug Class | HER2-Targeted Monoclonal Antibody |
| Manufacturer | Genentech / Roche; biosimilars available |
| Administration | Intravenous (IV) infusion or subcutaneous injection |
| FDA Approval | 1998 |
FDA-Approved Uses for Herceptin
Indications are based on FDA approval. Your healthcare provider determines appropriate use based on your specific diagnosis, stage, biomarker status, and overall clinical picture.
- HER2-positive early breast cancer — adjuvant (with chemotherapy)
- HER2-positive metastatic breast cancer — with chemotherapy (first-line)
- HER2-positive metastatic breast cancer — monotherapy (after chemotherapy)
- HER2-positive metastatic gastric/GEJ adenocarcinoma — with cisplatin and capecitabine or 5-FU (first-line)
How Does Herceptin Work?
Trastuzumab binds to the HER2 receptor, blocking downstream signaling pathways (PI3K/AKT, MAPK) that drive tumor cell proliferation and survival. It also mediates antibody-dependent cellular cytotoxicity (ADCC) via immune effector cells. By blocking HER2, trastuzumab inhibits growth of HER2-overexpressing cancer cells.
Dosage & Administration
IV: Loading dose 4 mg/kg, then 2 mg/kg weekly; or 8 mg/kg loading, then 6 mg/kg every 3 weeks. SC (Herceptin Hylecta): 600 mg every 3 weeks — fixed dose regardless of weight. Duration depends on indication (adjuvant: 1 year total; metastatic: until progression or unacceptable toxicity).
Dosing is individualized by the prescribing clinician. Never adjust your dose without consulting your healthcare provider. This information is educational only and does not replace the official prescribing information.
Warnings, Precautions & Side Effects
General Warning
Cardiomyopathy — can be severe/fatal; monitor LVEF. Embryo-fetal toxicity — can cause oligohydramnios, lung hypoplasia, and death. Pulmonary toxicity. Infusion reactions. Exacerbation of chemotherapy-induced neutropenia.
- Cardiomyopathy — monitor LVEF (boxed warning in some settings)
- Embryo-fetal toxicity (oligohydramnios, fetal death)
- Pulmonary toxicity
- Infusion reactions
Common Side Effects
- Fever/chills (infusion reactions)
- Nausea
- Fatigue
- Rash
- Diarrhea
- Cardiac dysfunction
- Headache
- Anemia
This is not a complete list. Always report new or worsening symptoms to your healthcare provider promptly.
Storage & Handling
Refrigerate at 2°C to 8°C (36°F to 46°F). Do not freeze.
BiologicHealthPlus provides temperature-monitored cold-chain specialty delivery for medications requiring refrigeration. Never use a medication if its storage conditions have been compromised.
Insurance Coverage, Prior Authorization & Patient Assistance
🛡️ Commercial Insurance
Herceptin is covered by most major commercial insurance plans when medically necessary and prior authorized. Coverage tier and cost-sharing vary by plan.
✅ Prior Authorization
Prior authorization is required by virtually all insurance plans for Herceptin. BiologicHealthPlus handles the complete prior authorization process at no cost to patients or providers.
🏥 Medicare Coverage
Medicare Part B covers this IV medication when administered in a clinical setting. Medicaid coverage varies by state.
🆓 Patient Assistance
Manufacturer patient assistance programs may be available for eligible uninsured or underinsured patients. Contact BiologicHealthPlus for a confidential eligibility review.
Prior Authorization Patient Assistance Insurance & Savings Medication Costs
Frequently Asked Questions — Herceptin
Herceptin was the first HER2-targeted therapy, FDA-approved in 1998. It binds HER2 receptors on tumor cells, blocking growth signals and triggering immune attack. It transformed outcomes in HER2-positive breast cancer.
Yes — multiple FDA-approved trastuzumab biosimilars are available, including Herzuma, Ogivri, Kanjinti, Trazimera, Ontruzant, and others. They are considered highly similar to Herceptin.
Yes — Herceptin Hylecta (trastuzumab and hyaluronidase-oysk) is a subcutaneous formulation given as a fixed 600 mg dose every 3 weeks. Phesgo combines SC trastuzumab with pertuzumab.
Herceptin (IV) is covered by Medicare Part B. Biosimilars may be preferred by some formularies. Prior authorization and HER2 biomarker documentation are required.
Related Medications & Conditions
Related Medications
Perjeta (pertuzumab) · Kadcyla (T-DM1) · Enhertu (trastuzumab deruxtecan) · Phesgo (pertuzumab/trastuzumab SC)
Related Conditions
HER2-positive breast cancer · HER2-positive gastric cancer · Early breast cancer (adjuvant)