Kadcyla (ado-trastuzumab emtansine)
Genentech / Roche · HER2-Targeted Antibody-Drug Conjugate (ADC)
What is Kadcyla? Kadcyla (ado-trastuzumab emtansine, T-DM1) is an antibody-drug conjugate (ADC) by Genentech combining trastuzumab (HER2 antibody) with emtansine (DM1, a microtubule inhibitor) via a stable linker. It is approved for HER2-positive early and metastatic breast cancer.
About Kadcyla
| Brand Name | Kadcyla |
| Generic / INN | ado-trastuzumab emtansine |
| Drug Class | HER2-Targeted Antibody-Drug Conjugate (ADC) |
| Manufacturer | Genentech / Roche |
| Administration | Intravenous (IV) infusion |
| FDA Approval | 2013 |
FDA-Approved Uses for Kadcyla
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 treatment in patients with residual invasive disease after neoadjuvant taxane-based and HER2-targeted therapy
- HER2-positive metastatic breast cancer — after prior trastuzumab and a taxane
How Does Kadcyla Work?
Kadcyla binds HER2 on tumor cells via the trastuzumab component, is internalized, then releases emtansine (DM1) intracellularly. DM1 binds tubulin, inhibiting microtubule polymerization and causing mitotic arrest and apoptosis. The ADC approach targets cytotoxin delivery specifically to HER2-overexpressing cells, reducing systemic toxicity.
Dosage & Administration
3.6 mg/kg IV every 3 weeks. First infusion over 90 minutes; subsequent infusions over 30 minutes if tolerated. Do not substitute Kadcyla for or with trastuzumab (Herceptin) or other HER2 agents — they are not interchangeable.
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
Hepatotoxicity — monitor LFTs; fatal hepatic failure reported. Cardiac toxicity — evaluate LVEF before and during treatment. Embryo-fetal toxicity. Thrombocytopenia. ILD/pneumonitis. Peripheral neuropathy. Do NOT substitute with trastuzumab (Herceptin).
- Hepatotoxicity (including fatal)
- Cardiotoxicity / decreased LVEF
- ILD/pneumonitis
- Thrombocytopenia
- Embryo-fetal toxicity
- Peripheral neuropathy
Common Side Effects
- Fatigue
- Nausea
- Musculoskeletal pain
- Thrombocytopenia
- Headache
- Elevated LFTs
- Peripheral neuropathy
- Constipation
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. Reconstituted and diluted solutions: refrigerate; use within 4 hours at room temperature.
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
Kadcyla 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 Kadcyla. 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 — Kadcyla
Kadcyla (ado-trastuzumab emtansine) is a HER2-targeted antibody-drug conjugate combining trastuzumab and a chemotherapy agent (DM1) linked together. It delivers the cytotoxin directly into HER2-positive tumor cells.
No — Kadcyla (ado-trastuzumab emtansine) must NEVER be substituted for trastuzumab (Herceptin) or other trastuzumab products. They are entirely different drugs despite both targeting HER2.
Kadcyla is used as adjuvant therapy in early HER2+ breast cancer with residual disease after neoadjuvant therapy, and as a later-line option in metastatic HER2+ breast cancer after prior trastuzumab and taxane.
Kadcyla is covered by Medicare Part B and commercial insurance for HER2+ breast cancer with prior authorization and HER2 biomarker documentation.
Related Medications & Conditions
Related Medications
Trastuzumab (Herceptin) · Enhertu (trastuzumab deruxtecan) · Perjeta (pertuzumab) · Verzenio (abemaciclib)
Related Conditions
HER2-positive breast cancer · Early breast cancer (residual disease) · Metastatic HER2+ breast cancer