Trastuzumab Emtansine
| Evidence Level: L4 | Predicted Indications: 4 |
Table of Contents
- Trastuzumab Emtansine
- Trastuzumab Emtansine: From HER2-Positive Breast Carcinoma to Progesterone-Receptor Positive Breast Cancer
Trastuzumab Emtansine: From HER2-Positive Breast Carcinoma to Progesterone-Receptor Positive Breast Cancer
One-Sentence Summary
Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate originally used to treat HER2-positive breast carcinoma. The TxGNN model predicts it may be effective for progesterone-receptor positive breast cancer, but this is largely a subpopulation of the already-approved indication rather than a true new use. Currently there are no registered clinical trials and 15 publications (mostly reviews, guidelines and case reports) linked to this prediction.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | HER2-positive breast carcinoma (the US license record has no indication text) |
| Predicted New Indication | Progesterone-receptor positive breast cancer |
| TxGNN Prediction Score | 99.82% |
| Evidence Level | L4 |
| US Market Status | Cancelled only (the single license, BLA125427, is listed as cancelled) |
| Number of NDAs | 1 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data is not available in the data compiled for this report. From the literature, T-DM1 is an antibody-drug conjugate: a HER2-targeting antibody (trastuzumab) linked to the cytotoxic payload DM1 (emtansine). Its activity depends on HER2 expression, not on progesterone receptor (PR) status.
HER2-positive tumors that are also PR-positive (HR+/HER2+) are already covered by the approved HER2-positive breast cancer indication. The very high TxGNN score most likely reflects the close relationship between these diseases in the knowledge graph, not a new therapeutic opportunity. In practice, this prediction describes a biomarker-defined subgroup of the original indication.
Other predicted indications in the data also overlap with the approved use:
- Normal breast-like subtype: typically HER2-low or HER2-negative, so the mechanistic basis is weak. No trials or literature were found (L5, Hold).
- Progesterone-receptor negative breast cancer: HER2-positive, PR-negative tumors are already covered. One terminated Phase 2 trial and reviews or case reports are linked (L3).
- Luminal A or B breast tumor: luminal B tumors can be HER2-positive (already covered), while luminal A tumors are generally HER2-negative. Evidence is indirect, and several retrieved papers are off-topic (L4).
Clinical Trial Evidence
Currently no related clinical trials are registered for the top predicted indication (PR-positive breast cancer).
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 35640077 | 2022 | Guideline | J Clin Oncol | ASCO guideline update on systemic therapy for advanced HER2-positive breast cancer |
| 29939838 | 2018 | Guideline | J Clin Oncol | Earlier ASCO guideline update; systematic review of 622 articles on advanced HER2-positive disease |
| 28259011 | 2017 | Guideline | Eur J Cancer | EGTM biomarker guideline: ER and PR should be measured in all invasive breast cancers; HER2 testing is mandatory to select anti-HER2 therapy, including ado-trastuzumab emtansine |
| 34215766 | 2021 | Cohort | Sci Rep | ChangeHER trial: prognostic relevance of gaining HER2 positivity in metastatic breast cancer treated with pertuzumab and/or T-DM1 |
| 33726508 | 2021 | Review | Future Oncol | Current treatment trends in HR+/HER2+ breast cancer; mentions T-DM1 among novel anti-HER2 agents |
| 39631485 | 2024 | Review | Pharmacol Res | Targeted and cytotoxic inhibitors in breast cancer, organized by HER2, HR, ER and PR status |
| 24892840 | 2013 | Review | Clin Adv Hematol Oncol | Integrating new data into metastatic breast cancer practice |
| 25873876 | 2015 | Case report | Case Rep Oncol | Dose-reduced T-DM1 was active and safe in a patient with acute hepatic dysfunction |
| 33482449 | 2021 | Case report | Int J Surg Case Rep | Favorable survival with combined treatment in a metastatic breast cancer patient on hemodialysis |
| 35251981 | 2022 | Case report | Front Oncol | Pyrotinib plus metronomic vinorelbine in HER2-positive breast cancer with leptomeningeal disease |
No PR-specific trial evidence was identified in this literature.
US Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| BLA125427 (cancelled) | KADCYLA (Genentech, Inc.) | Injection, powder, lyophilized, for solution | Not stated in the data compiled |
Cytotoxicity
| Item | Content |
|---|---|
| Cytotoxicity Classification | Antibody-drug conjugate (targeted delivery of a cytotoxic maytansinoid payload, DM1) |
| Myelosuppression Risk | Please refer to the package insert warnings and precautions |
| Emetogenicity Classification | Please refer to the package insert warnings and precautions |
| Monitoring Items | Please refer to the package insert warnings and precautions (typically blood counts and liver function) |
| Handling Protection | Please refer to the package insert warnings and precautions; follow institutional cytotoxic drug handling rules |
Safety Considerations
- Drug Interactions: The interaction screening returned 100 entries; the 20 reviewed here include several Major-level interactions, mainly with agents that affect bleeding or coagulation:
- Acetylsalicylic acid, deferasirox, abciximab, apixaban, argatroban, betrixaban, bivalirudin, cangrelor, caplacizumab and cilostazol (Major)
- Moderate-level examples include clarithromycin, metronidazole, naltrexone, rosuvastatin, simvastatin, tinidazole and cobicistat
Please refer to the package insert for warnings and contraindications.
Conclusion and Next Steps
Decision: Hold
Rationale: The predicted indication is a PR-positive subgroup of the already-approved HER2-positive breast cancer use, so it is not a true repurposing opportunity. T-DM1’s activity depends on HER2, not PR status. There are no registered trials and no PR-specific evidence, and the US license is listed as cancelled.
To proceed, the following is needed:
- Package insert warnings and contraindications (a blocking gap for safety screening)
- Detailed mechanism of action data from DrugBank
- Subgroup analyses of HER2-positive trials stratified by PR/hormone receptor status, to show whether PR-positive disease needs separate evaluation
- Clarification of the current US regulatory status, given the cancelled license
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.