What is the TROPION trial for triple negative breast cancer?

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Last updated: December 29, 2025View editorial policy

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The TROPION Trial and Triple-Negative Breast Cancer

The TROPION trial is not a study specifically designed for or relevant to triple-negative breast cancer (TNBC). The provided evidence contains no information about any trial named "TROPION" in the context of TNBC treatment or research.

What You Should Know About TNBC Treatment Instead

Since the TROPION trial does not appear in the current evidence base for TNBC, here are the established treatment approaches you should be aware of:

First-Line Metastatic TNBC Treatment

For PD-L1-positive metastatic TNBC, immune checkpoint inhibitor plus chemotherapy is the standard first-line therapy 1, 2:

  • Pembrolizumab plus chemotherapy is recommended for patients with PD-L1 Combined Positive Score (CPS) ≥10, improving median PFS from 5.6 to 9.7 months (HR 0.65, P=0.0012) 1
  • Atezolizumab plus nab-paclitaxel is approved for PD-L1-positive disease (≥1% expression on immune cells), improving PFS from 5.0 to 7.5 months (HR 0.62, P<0.001) and OS from 15.1 to 25 months 1

For PD-L1-negative disease, single-agent chemotherapy is preferred, with taxanes being the first choice if not previously used in the adjuvant setting 2.

Later-Line Treatment Options

After at least two prior therapies, sacituzumab govitecan is strongly recommended 3, 2:

  • The ASCENT trial demonstrated median PFS improvement to 5.6 months versus 1.7 months with standard chemotherapy (HR 0.41, P<0.0001) 3
  • Median OS improved to 12.1 months versus 6.7 months (HR 0.48, P<0.0001) 3

For patients with germline BRCA1/2 mutations, PARP inhibitors (olaparib or talazoparib) are preferred over chemotherapy after prior chemotherapy exposure 3, 2:

  • The OlympiAD trial showed median PFS of 7.0 months with olaparib versus 4.2 months with chemotherapy (HR 0.58, P<0.001), with even greater benefit in the TNBC subset (HR 0.39) 3
  • The EMBRACA trial demonstrated median PFS of 8.6 months with talazoparib versus 5.6 months with chemotherapy (HR 0.54, P<0.001) 3

Critical Caveats

  • PD-L1 testing is mandatory before initiating immunotherapy in metastatic TNBC, using the specific companion diagnostic validated for each agent (SP142 for atezolizumab, 22C3 for pembrolizumab) 1
  • Immunotherapy is only indicated if metastatic disease developed de novo or at least 12 months after completion of (neo)adjuvant chemotherapy 1, 2
  • Different PD-L1 assays are not interchangeable—the 22C3 assay evaluates tumor cells, lymphocytes, and macrophages, while SP142 evaluates immune cells in tumor and stroma 1

If you were asking about a different trial or if "TROPION" refers to a study in another cancer type, please clarify the specific context of your question.

References

Guideline

Immunotherapy in Breast Cancer

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Treatment for Metastatic Triple-Negative Breast Cancer

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

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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