When should I choose Kadcyla (ado-trastuzumab emtansine) for HER2-positive breast cancer treatment?

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Last updated: June 12, 2025View editorial policy

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From the Guidelines

Kadcyla (ado-trastuzumab emtansine) should be chosen for HER2-positive breast cancer treatment in patients who have progressed during or after first-line HER2-targeted therapy, particularly those who have not received T-DM1, as it has shown significant improvement in progression-free survival and overall survival compared to other treatments 1.

Clinical Scenarios for Kadcyla Use

  • As a second-line treatment for patients with metastatic HER2-positive breast cancer who previously received trastuzumab and a taxane, separately or in combination.
  • For patients with disease progression after treatment with trastuzumab-based therapy without pertuzumab, a line of therapy containing T-DM1 may be considered.

Key Considerations

  • The standard dose of Kadcyla is 3.6 mg/kg given intravenously every 3 weeks until disease progression or unacceptable toxicity occurs.
  • Before starting Kadcyla, patients should have baseline liver function tests, cardiac function assessment, and complete blood counts, as the medication can cause hepatotoxicity, cardiotoxicity, and myelosuppression.
  • Kadcyla has shown activity in the second-line setting, with a statistically significant improvement in progression-free survival and overall survival compared to lapatinib plus capecitabine 1.

Benefits and Risks

  • Kadcyla has been shown to maintain health-related quality of life for a longer duration compared to other treatments, with a median of 7.7 months for T-DM1 1.
  • The medication can cause significant side effects, including thrombocytopenia and increased serum aminotransferase levels, which should be closely monitored.

Recommendation

Based on the most recent and highest quality evidence, Kadcyla should be considered as a second-line treatment for patients with metastatic HER2-positive breast cancer who have progressed during or after first-line HER2-targeted therapy, particularly those who have not received T-DM1 1.

From the Research

Indications for Kadcyla

Kadcyla (ado-trastuzumab emtansine) is indicated for the treatment of HER2-positive breast cancer. The following are scenarios where Kadcyla may be considered:

  • Metastatic Breast Cancer: Kadcyla is approved for the treatment of patients with HER2-positive metastatic breast cancer who have previously received trastuzumab and a taxane, separately or in combination 2, 3, 4.
  • Adjuvant Treatment: Kadcyla is also approved for the adjuvant treatment of patients with HER2-positive early breast cancer who have residual invasive disease after neoadjuvant taxane-based chemotherapy and trastuzumab-based treatment 5.

Patient Selection

When selecting patients for Kadcyla treatment, consider the following:

  • HER2-positive Status: Patients should have confirmed HER2-positive breast cancer.
  • Previous Treatment: Patients should have previously received trastuzumab and a taxane, separately or in combination, for metastatic breast cancer.
  • Residual Disease: For adjuvant treatment, patients should have residual invasive disease after neoadjuvant taxane-based chemotherapy and trastuzumab-based treatment.

Efficacy and Safety

Kadcyla has demonstrated efficacy in prolonging progression-free survival and overall survival in patients with HER2-positive advanced breast cancer 2, 3, 4. The safety profile of Kadcyla includes common adverse reactions such as fatigue, nausea, increased transaminases, and thrombocytopenia 2, 3, 5, 4.

Combination Therapy

The combination of Kadcyla with atezolizumab did not show a clinically meaningful improvement in progression-free survival and was associated with more adverse events in a phase 2 trial 6. Further study is warranted in a subpopulation of patients with PD-L1-positive, HER2-positive advanced breast cancer.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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