Topotecan
| Evidence Level: L5 | Predicted Indications: 2 |
Table of Contents
Topotecan: Female breast carcinoma
One-Sentence Summary
Topotecan is a topoisomerase I inhibitor chemotherapy, originally used to treat ovarian cancer and related ovarian tumour types. The TxGNN model predicts it may be effective for female breast carcinoma, with 3 clinical trials (all early-phase or terminated, none with usable efficacy results) and 20 publications (mostly reviews, preclinical work, and small phase 2 or pilot studies) currently touching on this direction.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not recorded in the local data |
| Predicted New Indication | Female breast carcinoma |
| TxGNN Prediction Score | 0.9992 |
| Evidence Level | L5 |
| India Market Status | Listed in a compiled Indian medicine price dataset (4 of 4) – CDSCO approval status is not included in this data |
| Number of Listed Products | 4 (valid: 4) |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available in the data compiled for this report. Based on known pharmacology, topotecan is a topoisomerase I inhibitor. It causes DNA strand breaks and replication-associated cell death in rapidly dividing tumour cells. Its activity in ovarian cancer is established.
Ovarian and breast cancers are both hormone-related gynaecological-type malignancies, and they share familial links through BRCA-related hereditary syndromes. The score comes from the TxGNN model (deep learning) and may reflect similarities the model learned between related diseases, not biological evidence. Mechanistically, topoisomerase I inhibition is plausible in breast cancer. A 2023 preclinical study (PMID 37987734) suggests that topoisomerase 1 inhibition is synthetically lethal in MYC-driven breast cancer cells through aberrant R-loop accumulation.
There are also cautionary signals. Topotecan is a substrate of the BCRP/ABCG2 efflux transporter, which was first identified in a multidrug-resistant breast cancer cell line and may reduce drug accumulation and cause resistance. A phase 2 study of continuous infusional topotecan in advanced breast cancer also found no evidence of increased efficacy. The very high TxGNN score is a computational prediction and is not clinical evidence.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT00006032 | Phase 2 | Terminated | Not reported | Intensive-dose topotecan, ifosfamide/mesna and etoposide followed by autologous stem cell rescue in metastatic breast cancer; no efficacy data available |
| NCT02419495 | Phase 1 | Terminated | 221 | Safety study of selinexor with several standard chemotherapies (topotecan among the options) in advanced cancers; breast-specific topotecan signal cannot be isolated |
| NCT06840886 | Phase 1 | Recruiting | 426 | First-in-human study of PHST001 alone or with anticancer therapies in advanced solid tumours; topotecan’s role in breast cancer is unclear and no results are available |
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 9413954 | 1997 | Phase 2 trial | British Journal of Cancer | Continuous infusional topotecan in advanced breast and non-small-cell lung cancer showed no evidence of increased efficacy |
| 11455218 | 2001 | Pilot study | Onkologie | Topotecan as primary chemotherapy for brain metastases in metastatic breast cancer |
| 9425961 | 1997 | Review | Seminars in Oncology | Discusses the potential role of topotecan in advanced breast cancer |
| 37987734 | 2023 | Preclinical | Cancer Research | Topoisomerase 1 inhibition is synthetically lethal in MYC-driven cancer via R-loop accumulation |
| 25236865 | 2015 | Review | The AAPS Journal | BCRP/ABCG2 efflux transporter and its role in topotecan transport and resistance |
| 10930538 | 2000 | Preclinical | Biochemical Pharmacology | BCRP expression in topotecan-resistant human breast carcinoma cells |
| 10472342 | 1999 | Preclinical | Anticancer Research | Xenograft comparison of doxorubicin, cisplatin, irinotecan and topotecan in colon, lung and breast carcinomas |
| 39657238 | 2024 | Preclinical | ACS Applied Materials & Interfaces | Topotecan-loaded drug-gene nanoparticles for metastatic breast cancer |
| 7910993 | 1994 | Review | World Journal of Surgery | General management of metastatic breast cancer |
| 27084985 | 2016 | Review | Aging | Metronomic chemotherapy for triple-negative breast cancer |
India Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| 224632 | Topotel 4mg Injection | Vial of 4 ml injection | Not specified in the data compiled |
| 46400 | Cantop 2.5mg Injection | Vial of 1 injection | Not specified in the data compiled |
| 217920 | Topotec 2.5mg Injection | Vial of 2.5 ml injection | Not specified in the data compiled |
| 224022 | Topocan 4mg Injection | Vial of 10 ml injection | Not specified in the data compiled |
Cytotoxicity
| Item | Content |
|---|---|
| Cytotoxicity Classification | Conventional cytotoxic (topoisomerase I inhibitor, camptothecin class) |
| Emetogenicity Classification | Please refer to the package insert warnings and precautions |
| Monitoring Items | Complete blood count with differential, renal function, and monitoring for diarrhoea and respiratory symptoms |
| Handling Protection | Must follow cytotoxic drug handling regulations |
Safety Considerations
- Disease-level contraindication signals (knowledge graph, not label text): thrombocytopenia, neutropenia, agranulocytosis, anaemia, interstitial lung disease, pulmonary fibrosis, diarrhoeal disease, and impaired renal function.
- Drug Interactions: 296 interactions were recorded. The main ones are:
- Major: deferiprone and samarium (153Sm) lexidronam, both of which carry additive myelosuppression concerns.
- Moderate: eliglustat, rolapitant, iobenguane (I-131), palifermin, strontium chloride Sr-89, and ibritumomab tiuxetan.
- Minor: levofloxacin and caffeine.
Package insert warnings and contraindications were not available in the data compiled for this report. Please refer to the package insert for the full safety profile.
Conclusion and Next Steps
Decision: Hold
Rationale: The TxGNN score is very high, but the supporting clinical evidence for breast cancer is weak. The three listed trials are early-phase or terminated with no efficacy results, and the literature consists mainly of reviews and preclinical work. The one directly relevant phase 2 study found no evidence of increased efficacy. Topotecan is already marketed in India as an injectable (4 registrations), but its approved indication text is not available, and the label safety review cannot proceed without package insert data.
To proceed, the following is needed:
- Package insert warnings and contraindications from the Indian marketed products, plus their approved indication text
- Detailed mechanism of action data
- Controlled clinical data for topotecan in breast cancer, such as phase 2 or 3 trials with efficacy results
- A comparison against current standard-of-care breast cancer regimens, including consideration of BCRP-mediated resistance
Other predicted indications (for reference): Adult germ cell tumour (TxGNN 0.9957, evidence level L2) is the next most supported candidate, with a completed phase 2 trial of paclitaxel and topotecan (n=20), although most retrieved evidence concerns paediatric solid tumours. Topotecan is already labelled for ovarian yolk sac tumour, so extrapolation is biologically plausible.
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.