Pertuzumab
| Evidence Level: L1 | Predicted Indications: 10 |
Table of Contents
- Pertuzumab
- Pertuzumab: From HER2-Positive Breast Cancer to Progesterone-Receptor Positive Breast Cancer
Pertuzumab: From HER2-Positive Breast Cancer to Progesterone-Receptor Positive Breast Cancer
One-Sentence Summary
Pertuzumab is a HER2-targeted antibody originally used to treat HER2-positive breast cancer. The TxGNN model predicts it may be effective for progesterone-receptor positive breast cancer, which is essentially a hormone-receptor subset of the already-treated disease. Currently, 1 clinical trial and 20 publications support this direction, including several randomised neoadjuvant studies.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | HER2-positive breast carcinoma |
| Predicted New Indication | Progesterone-receptor positive breast cancer |
| TxGNN Prediction Score | 99.93% |
| Evidence Level | L1 |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 3 |
| Recommended Decision | Proceed with Guardrails |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available in the data compiled for this report. Based on known information, pertuzumab binds the extracellular dimerisation domain of HER2 and blocks HER2/HER3 heterodimerisation. This dampens downstream PI3K/AKT signalling.
Many HER2-positive tumours also express progesterone receptor (the HR+/HER2+ subtype). In these tumours the HER2-driven mechanism is the same as in the approved indication. The prediction is therefore better seen as a receptor-defined subset of the labelled disease than as a true repurposing. The trials and publications are driven by HER2 status, and PR status is a co-existing tumour characteristic.
Endocrine-therapy combinations are being explored in this subgroup. Examples are the WSG TP-II trial (trastuzumab + pertuzumab + endocrine therapy versus chemotherapy) and the PERTAIN study (pertuzumab + trastuzumab + aromatase inhibitor).
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT04629846 | Phase 3 | Completed | 517 | Biosimilar QL1209 vs reference pertuzumab, each with trastuzumab and docetaxel, in early or locally advanced HER2-positive, ER/PR-negative breast cancer. This is a biosimilar equivalence study, so it supports pertuzumab efficacy in HER2-positive disease only indirectly. It does not cover the PR-positive population. |
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 42150145 | 2026 | RCT | J Clin Oncol | WSG TP-II survival analysis: neoadjuvant trastuzumab + pertuzumab + endocrine therapy vs chemotherapy in HR+/HER2+ early breast cancer |
| 38906970 | 2024 | RCT | Br J Cancer | Phase III equivalence of pertuzumab biosimilar QL1209 vs Perjeta in HER2-positive, ER/PR-negative neoadjuvant therapy |
| 28945833 | 2017 | RCT | Ann Oncol | WSG-ADAPT HER2+/HR-: 12 weeks of neoadjuvant trastuzumab + pertuzumab with or without weekly paclitaxel (de-escalation) |
| 27179402 | 2016 | Cohort (5-year follow-up of a phase 2 RCT) | Lancet Oncol | NeoSphere 5-year progression-free survival, disease-free survival and safety of neoadjuvant pertuzumab + trastuzumab |
| 35640077 | 2022 | Guideline | J Clin Oncol | ASCO guideline update on systemic therapy for advanced HER2-positive breast cancer |
| 41387082 | 2026 | Cohort | Breast | Adjuvant ovarian function suppression and aromatase inhibitors in premenopausal HR+/HER2+ patients |
| 27057657 | 2016 | Review | Cancer Treat Rev | HR+/HER2+ breast cancer: current status and future directions |
| 40983817 | 2025 | Review | Breast Cancer | Signalling pathway interactions and clinical translation in HR+/HER2+ breast cancer |
| 30922805 | 2019 | Phase IIIb trial | Clin Breast Cancer | SAPPHIRE: pertuzumab + subcutaneous trastuzumab + taxane in HER2-positive metastatic breast cancer; safety and tolerability |
| 41401771 | 2026 | RCT | ESMO Open | Phase III equivalence of pertuzumab biosimilar TQB2440 vs reference pertuzumab in HER2-positive, ER/PgR-negative disease |
Singapore Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| SIN14501P | Perjeta Concentrate for Solution for Infusion 420 mg/14 mL | Concentrate for infusion solution | Not specified in the compiled data |
| SIN16247P | Phesgo Solution for Subcutaneous Injection 1200 mg/600 mg / 15 mL | Injection solution | Not specified in the compiled data |
| SIN16248P | Phesgo Solution for Subcutaneous Injection 600 mg/600 mg / 10 mL | Injection solution | Not specified in the compiled data |
Cytotoxicity
| Item | Content |
|---|---|
| Cytotoxicity Classification | Targeted therapy (anti-HER2 monoclonal antibody), not a conventional cytotoxic agent |
| Myelosuppression Risk | Please refer to the package insert warnings and precautions. Myelosuppression is mainly associated with the combined chemotherapy (e.g., docetaxel). |
| Emetogenicity Classification | Please refer to the package insert warnings and precautions |
| Monitoring Items | Cardiac function (LVEF), as cardiac safety is the focus of studies such as TRYPHAENA and BERENICE. Also monitor CBC and liver and renal function, especially with combined chemotherapy. |
| Handling Protection | Please refer to the package insert warnings and precautions |
Safety Considerations
- Drug Interactions:
- Idelalisib: Moderate interaction (DDInter).
- The pharmacology database also lists the HER2 (ERBB2) receptor as pertuzumab's target. This is a target relationship, not a drug interaction.
Please refer to the package insert for other safety information, including warnings and contraindications.
Conclusion and Next Steps
Decision: Proceed with Guardrails
Rationale: PR-positive breast cancer is largely a receptor-defined subset of the approved HER2-positive indication, and the mechanism is the same. Randomised studies (e.g., WSG TP-II, NeoSphere) include HR+/HER2+ patients. The only registered trial listed is a biosimilar study in ER/PR-negative patients, which is indirect evidence for the PR-positive subgroup.
To proceed, the following is needed:
- Package insert warnings and contraindications (HSA label), which is a blocking gap for safety screening
- Detailed mechanism of action data (DrugBank)
- Approved indication text for the Singapore registrations, to confirm how the current labels define the HER2-positive population
- Subgroup efficacy data by PR status, and confirmation of HER2 positivity in the target patients
- A cardiac safety monitoring plan (LVEF), particularly with anthracycline-containing regimens
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.