Pertuzumab
| Evidence Level: L5 | Predicted Indications: 6 |
Table of Contents
Pertuzumab: Ectomesenchymoma
One-Sentence Summary
Pertuzumab is an anti-HER2 antibody originally used to treat HER2-positive breast carcinoma. The TxGNN model predicts it may be effective for ectomesenchymoma, with 1 clinical trial and 20 publications currently supporting this direction. Most of this evidence reflects use in the already-approved HER2-positive population, so it is better described as a subgroup of the current indication than a true new indication.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not recorded in the local data |
| Predicted New Indication | Ectomesenchymoma |
| TxGNN Prediction Score | 0.9971 |
| Evidence Level | L5 |
| Canada Market Status | Marketed (marketed DINs: 4 of 4) |
| Number of DINs | 4 (marketed: 4) |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data is not available in the data compiled for this report. Based on the rationale compiled, pertuzumab binds a specific region (subdomain II) of HER2 and prevents HER2 from pairing with HER3. This pairing normally drives the PI3K/AKT and MAPK growth signalling pathways, so blocking it dampens tumour growth signals.
In breast cancer, many HER2-positive tumours also carry hormone receptors (ER and/or PR). Laboratory and clinical work suggests that the HER2 and hormone-receptor pathways communicate with each other. This is why pertuzumab is combined with trastuzumab and endocrine therapy in studies such as WSG-TP-II and PERTAIN.
An important caveat: the benefit applies to the HER2-positive subset of PR-positive tumours. Having PR-positive status alone does not make a tumour a pertuzumab target. This prediction is therefore largely a subpopulation of the approved HER2-positive indication, not a true repurposing opportunity.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT04629846 | Phase 3 | Completed | 517 | Randomized, double-blind equivalence trial of pertuzumab biosimilar QL1209 vs reference pertuzumab, each with trastuzumab and docetaxel, in early or locally advanced HER2-positive, ER/PR-negative breast cancer. It is a biosimilar comparison and does not establish a new indication. |
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 38906970 | 2024 | RCT | British Journal of Cancer | Phase III equivalence trial of the QL1209 pertuzumab biosimilar vs reference pertuzumab in neoadjuvant HER2-positive, ER/PR-negative breast cancer |
| 42150145 | 2026 | RCT | Journal of Clinical Oncology | WSG TP-II survival analysis: neoadjuvant trastuzumab + pertuzumab plus endocrine therapy vs chemotherapy in HR+/HER2+ early breast cancer |
| 28945833 | 2017 | RCT | Annals of Oncology | WSG-ADAPT HER2+/HR- phase II: 12 weeks of dual blockade with or without weekly paclitaxel |
| 35640077 | 2022 | Guideline | Journal of Clinical Oncology | ASCO guideline update on systemic therapy for advanced HER2-positive breast cancer |
| 27179402 | 2016 | Cohort | The Lancet Oncology | NeoSphere 5-year analysis: progression-free and disease-free survival and safety of neoadjuvant pertuzumab + trastuzumab |
| 41401771 | 2026 | RCT | ESMO Open | Phase III equivalence trial of the pertuzumab biosimilar TQB2440 in HER2-positive, ER/PgR-negative early or locally advanced breast cancer |
| 27057657 | 2016 | Review | Cancer Treatment Reviews | Overview of HR+/HER2+ breast cancer and the crosstalk between hormone-receptor and HER2 pathways |
| 40983817 | 2025 | Review | Breast Cancer | Signalling pathway interactions and clinical translation in HR+/HER2+ breast cancer |
| 41387082 | 2026 | Retrospective cohort | The Breast | Adjuvant ovarian function suppression and aromatase inhibitors in premenopausal HR+/HER2+ patients |
| 30922805 | 2019 | Phase IIIb | Clinical Breast Cancer | SAPPHIRE: pertuzumab with subcutaneous trastuzumab and a taxane in HER2-positive metastatic breast cancer |
Canada Market Information
| DIN | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| 02405016 | PERJETA | Not specified | Not specified |
| 02512920 | PHESGO | Not specified | Not specified |
| 02512912 | PHESGO | Not specified | Not specified |
| 02405024 | PERJETA-HERCEPTIN | Not specified | Not specified |
All four authorizations are valid licences. Dosage form and indication text were not available in the data compiled for this report.
Cytotoxicity
| Item | Content |
|---|---|
| Cytotoxicity Classification | Targeted therapy (HER2-directed monoclonal antibody), not a conventional cytotoxic |
| Myelosuppression Risk | Please refer to the package insert warnings and precautions (pertuzumab is usually given with taxane chemotherapy, which carries its own myelosuppression risk) |
| Emetogenicity Classification | Please refer to the package insert warnings and precautions |
| Monitoring Items | Please refer to the package insert; cardiac function monitoring is commonly used with anti-HER2 therapy, and CBC, liver and renal function apply to the chemotherapy partners |
| Handling Protection | Please refer to the package insert warnings and precautions |
Safety Considerations
Drug Interactions (2 records):
- Idelalisib: Moderate interaction level.
- ERBB2 (HER2): This is a pharmacological target record, not a drug interaction. It confirms that pertuzumab acts on HER2 and is used for HER2-overexpressing breast cancer in combination with other agents.
Please refer to the package insert for warnings and contraindications.
Conclusion and Next Steps
Decision: Hold
Rationale: The evidence is strong for pertuzumab in HER2-positive breast cancer (Phase 3 and Phase 2 randomized data), but that is the already-approved indication. For PR-positive disease specifically, the benefit comes from the HER2-positive subset, and the only registered trial is a biosimilar equivalence study in PR-negative patients. This is a subgroup of the existing indication, not a distinct repurposing opportunity, and the score reflects model prediction rather than new clinical proof. The data pack also lacks label safety information and mechanism data, which blocks formal safety screening.
To proceed, the following is needed:
- Health Canada package insert warnings and contraindications (currently missing; this blocks safety screening)
- Detailed mechanism of action data from DrugBank
- Analysis of whether PR status changes pertuzumab benefit within HER2-positive disease, for example the retrospective finding that PR status may be a stronger determinant of pertuzumab benefit than ER status (PMID 37723497)
- Confirmation of Canadian approved indication text and dosage forms for each DIN
- Clarification of whether this prediction represents any use beyond the current HER2-positive label
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.