Palbociclib
| Evidence Level: L2 | Predicted Indications: 10 |
Table of Contents
Palbociclib: From Breast Cancer to Myeloid Leukemia
One-Sentence Summary
Palbociclib is a CDK4/6 inhibitor established for HR+/HER2-negative metastatic breast cancer. Among 10 TxGNN-predicted indications in this evidence pack, myeloid leukemia (AML) is the only candidate backed by meaningful clinical and mechanistic evidence, with 5 clinical trials (1 completed Phase 1/2) and 10+ publications supporting the direction — the drug’s top-ranked prediction (hyperthyroidism) has zero supporting evidence and was not selected as the reporting candidate.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not on file in this jurisdiction (drug not marketed); globally approved for HR+/HER2-negative metastatic breast cancer, as confirmed across the trial/literature evidence in this pack |
| Predicted New Indication | Myeloid Leukemia (Acute Myeloid Leukemia, AML) |
| TxGNN Prediction Score | 98.94% |
| Evidence Level | L2 |
| EU Market Status | Not Marketed |
| Number of Authorizations | 0 |
| Recommended Decision | Proceed with Guardrails |
Why is This Prediction Reasonable?
Note on candidate selection: TxGNN’s #1-ranked prediction for palbociclib (hyperthyroidism, score 0.994) has no supporting trials or literature and no plausible mechanistic link — it is a pure graph-prediction artifact. Several other top-10 candidates (thrombotic disease, multiple endocrine neoplasia) show evidence that actively contradicts the hypothesis or reflects disease-ontology mapping errors (see Safety Considerations). Myeloid leukemia (rank 6, score 0.989) is the only candidate in this bundle with real clinical-trial and translational support, so this report focuses on it.
Detailed regulatory-grade mechanism of action data is not available for this jurisdiction (data gap). However, the literature within this evidence pack consistently describes palbociclib as a CDK4/6 (cyclin-dependent kinase 4/6) inhibitor that blocks the CDK4/6–Rb pathway, arresting tumor cells in G1 phase — the mechanism underlying its approval in breast cancer.
Acute myeloid leukemia frequently shows CDK4/6–Rb pathway dysregulation, including CDK6-dependent proliferation in FLT3-ITD-mutated and MLL-rearranged subtypes, and CCND2/CCND3-driven cell-cycle activation in t(8;21) AML. This shared cell-cycle dependency provides a plausible mechanistic bridge from the approved breast cancer indication to AML.
Multiple preclinical and early-phase clinical studies substantiate this: palbociclib combined with venetoclax/azacitidine shows synergistic pro-apoptotic activity in AML models and can overcome venetoclax resistance; combination with CPX-351 has completed a Phase 1/2 trial with safety/efficacy signals; and case reports describe successful use in refractory therapy-related AML. Confirmatory randomized controlled trial data, however, is still lacking.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT03844997 | Phase 1/2 | Completed | 35 | Palbociclib + CPX-351 in AML; evaluated safety, tolerability, and response rate (CR/CRi) |
| NCT03132454 | Phase 1 | Active, not recruiting | 32 | Palbociclib alone and combined with sorafenib/decitabine/dexamethasone in relapsed/refractory leukemias |
| NCT05627232 | Phase 1 | Recruiting | 24 | Palbociclib pre-treatment followed by CPX-351 ± tazemetostat in relapsed/refractory AML |
| NCT02310243 | Phase 1/2 | Unknown | 50 | Palbociclib in MLL-rearranged acute leukemias (AML/ALL) |
| NCT03878524 | Phase 1 | Terminated (n=2) | 2 | SMMART molecular-guided combination platform trial; low evidentiary weight due to early termination |
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 36400926 | 2023 | Review | Leukemia | Reviews cell-cycle and apoptosis targeting (incl. CDK4/6 inhibition) to overcome AML chemoresistance |
| 38430306 | 2024 | Case Report | Cancer Chemother Pharmacol | Successful palbociclib + venetoclax + azacitidine in refractory therapy-related AML |
| 36076608 | 2022 | Preclinical/Translational | Biomed Pharmacother | Palbociclib enhances venetoclax + azacitidine antitumor activity in AML |
| 41468895 | 2026 | Preclinical | Cell Reports Medicine | Palbociclib + venetoclax overcomes venetoclax resistance across 302 AML patient samples and PDX models |
| 33068248 | 2021 | Preclinical | Int J Hematol | CDK4/6 + autophagy co-inhibition induces apoptosis in t(8;21) AML cells |
| 34430715 | 2021 | Preclinical (xenograft) | Biochem Biophys Rep | In vivo efficacy of CDK4/6 + autophagy co-inhibition in t(8;21) AML mouse model |
| 27323399 | 2016 | Mechanistic | Oncotarget | Identifies FLT3-ITD–HCK–CDK6 axis driving AML proliferation, rationale for CDK6-targeted therapy |
| 30381403 | 2018 | Genetic Study | Blood Advances | Recurrent CCND3 mutations found in MLL-rearranged AML, supporting cell-cycle-directed therapy |
| 40482924 | 2025 | Preclinical (drug delivery) | J Control Release | Antibody-mediated codelivery of FLT3 and CDK4/6 (palbociclib) dual inhibitors for AML |
| 34958208 | 2022 | Preclinical (drug discovery) | J Med Chem | Discovery of dual CDK6/PIM1 inhibitors building on CDK6-targeting rationale in AML |
EU Market Information
Palbociclib currently has no marketing authorization on file in this jurisdiction (market status: Not Marketed; 0 authorizations recorded). No product/dosage-form data is available to tabulate.
Cytotoxicity
| Item | Content |
|---|---|
| Cytotoxicity Classification | Targeted therapy (CDK4/6 inhibitor) — not a conventional cytotoxic chemotherapeutic |
| Myelosuppression Risk | High — preclinical and clinical literature in this pack repeatedly note palbociclib-induced myelosuppression and hematological adverse effects (e.g., PMID 39940918, 40330925) |
| Emetogenicity Classification | Please refer to the SmPC warnings and precautions (no emetogenicity data in this evidence pack) |
| Monitoring Items | CBC with differential (neutropenia surveillance), liver function; thromboembolic monitoring given pharmacovigilance signals (see Safety Considerations) |
| Handling Protection | As an oncology therapeutic, standard cytotoxic/hazardous drug handling precautions are recommended pending formal SmPC classification |
Safety Considerations
Official regional safety data (key warnings, contraindications, DDI) is not available (data gap; SmPC not on file for this jurisdiction). Please refer to the SmPC for safety information once available.
Signal identified from this evidence pack (not part of official labeling): Multiple independent pharmacovigilance studies (FAERS disproportionality analyses and real-world cohorts — PMIDs 36794339, 39123221, 39083396, 41496429) consistently associate CDK4/6 inhibitors, including palbociclib, with an increased risk of thromboembolic events. This is directly relevant to a prospective AML population, which may already carry elevated baseline thrombotic risk, and should be factored into any trial design or safety monitoring plan.
Conclusion and Next Steps
Decision: Proceed with Guardrails
Rationale: Palbociclib in AML has a coherent cell-cycle mechanistic rationale, multiple completed/ongoing early-phase trials (including one completed Phase 1/2 combination study), and consistent preclinical synergy data with venetoclax/azacitidine and CPX-351 — but no randomized controlled trial confirms efficacy, and formal regional safety labeling is absent.
To proceed, the following is needed:
- Official MOA and SmPC data (warnings, contraindications) — currently a blocking data gap (DG001/DG002)
- Design or monitoring of a randomized Phase 2 trial in AML combination regimens
- Explicit thromboembolic risk assessment and monitoring plan, given pharmacovigilance signals from CDK4/6 inhibitor class data
- Regulatory pathway clarification, since the drug is not currently marketed in this jurisdiction
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.