Palbociclib
| Evidence Level: L5 | Predicted Indications: 4 |
Table of Contents
Palbociclib: From Breast Cancer to Hyperthyroidism
One-Sentence Summary
Palbociclib is a CDK4/6 inhibitor used in hormone receptor-positive breast cancer. The TxGNN model predicts it may be effective for hyperthyroidism, but no clinical trials and no publications currently support this direction. The prediction rests on a computational score alone.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not stated in the registration data compiled for this report; palbociclib is a CDK4/6 inhibitor used in HR+/HER2- breast cancer |
| Predicted New Indication | Hyperthyroidism |
| TxGNN Prediction Score | 0.9944 |
| Evidence Level | L5 (model prediction only) |
| India Market Status | Listed in a compiled Indian medicine price dataset (3 of 3) – CDSCO approval status is not included in this data |
| Number of Listed Products | 3 (valid: 3) |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available in the data compiled for this report. Palbociclib is a selective CDK4/6 inhibitor. It blocks cell-cycle progression from G1 to S phase, and its efficacy in breast cancer is established.
No plausible link between CDK4/6 inhibition and excess thyroid hormone production is supported by the available data. The high TxGNN score is a computational association only. There is no evidence of a shared mechanism between the original and new indications. Treat this prediction as a hypothesis that needs mechanistic validation, not as a supported repurposing direction.
India Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| 181013 | Primcyv 75mg Capsule (Dr Reddy’s Laboratories Ltd) | Bottle of 21 capsules | Not stated |
| 178599 | Primcyv 125mg Capsule (Dr Reddy’s Laboratories Ltd) | Bottle of 21 capsules | Not stated |
| 180824 | Primcyv 100mg Capsule (Dr Reddy’s Laboratories Ltd) | Bottle of 21 capsules | Not stated |
All three registrations are valid single-ingredient oral products. There are no cancelled registrations.
Cytotoxicity
| Item | Content |
|---|---|
| Cytotoxicity Classification | Targeted therapy (CDK4/6 inhibitor), not a conventional cytotoxic agent |
| Myelosuppression Risk | Medium to high (neutropenia is the characteristic adverse effect) |
| Emetogenicity Classification | Low |
| Monitoring Items | CBC with differential, liver function |
| Handling Protection | Please refer to the package insert warnings and precautions |
Safety Considerations
- Drug Interactions: 100 interacting drugs were identified. Major-level interactions include:
- Clarithromycin
- Cobicistat
- Deferiprone
- Samarium (153Sm) lexidronam
- Moderate-level interactions include:
- Aprepitant
- Dexamethasone
- Cimetidine
- Simvastatin
- Cilostazol
- Cisapride
- Several azole antifungals (miconazole, clotrimazole)
Please refer to the package insert for warnings and contraindications.
Conclusion and Next Steps
Decision: Hold
Rationale: The hyperthyroidism prediction has no supporting clinical trials or literature, and no mechanistic link to CDK4/6 inhibition is evident. It is a model output only (L5).
For context, other predictions for this drug have more support. Myeloid leukemia has four registered early-phase trials and substantial preclinical work, and rheumatoid arthritis has preclinical and case-report evidence. Both would be more reasonable starting points for further evaluation than hyperthyroidism.
To proceed, the following is needed:
- Mechanism of action data and a biological rationale linking CDK4/6 inhibition to thyroid hormone excess
- Preclinical studies in thyroid or hyperthyroidism models
- Package insert warnings and contraindications for the India-registered products
- Approved indication text for the three registrations
- A plan for managing the drug interactions, especially the major-level ones
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.