Palbociclib
Palbociclib (brand name Ibrance) is a small-molecule, orally administered inhibitor of cyclin-dependent kinases 4 and 6 (Cdk4/6), developed by Pfizer and approved by the US Food and Drug Administration for the treatment of hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2−) metastatic breast cancer.
Palbociclib (brand name Ibrance) is a small-molecule, orally administered inhibitor of cyclin-dependent kinases 4 and 6 (Cdk4/6), developed by Pfizer and approved by the US Food and Drug Administration for the treatment of hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2−) metastatic breast cancer. Cdk4 and cyclin-dependent kinase 6 (CDK6) are serine/threonine kinases that, in complex with cyclin D, phosphorylate the retinoblastoma protein (Rb), releasing transcription factors that drive cell cycle progression from G1 into S phase. By competitively inhibiting the ATP-binding sites of Cdk4 and CDK6, palbociclib arrests tumor cells in G1, suppressing aberrant proliferation. This mechanism positions it as a cornerstone of endocrine-based combination strategies in luminal breast cancer, where cyclin D overactivation is a frequent oncogenic driver.
Beyond its cytostatic role, palbociclib exerts pleiotropic effects on the tumor microenvironment, including the induction of cellular senescence in both cancer cells and stromal compartments. These non-cell-autonomous consequences — encompassing immune modulation, paracrine signaling changes, and metabolic reprogramming — have broadened investigational interest beyond breast cancer to malignancies such as dedifferentiated liposarcoma and esophageal squamous cell carcinoma, and have raised important questions about how Cdk4/6 inhibition reshapes antitumor immunity and treatment resistance.
Where the papers sit
13 papers from the last 6 months study palbociclib directly · updated from PubMed 3 Oct 2026
Study type 2 clinical trials · 3 observational · 2 human data · 2 preclinical · 4 unclassified
Themes 3 themes
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CDK4/6 Inhibition in Breast Cancer
CDK4/6 inhibitor use in metastatic breast cancer is being defined by real-world treatment patterns, safety, age-related comorbidity and survival. Combination strategies add ipatasertib to endocrine therapy or CSF1R blockade to counter treatment-associated immunosuppression. Biomarker work links metastasis in triple-negative disease to a targetable miR-342-E2F network. The field is moving toward more individualized combinations and immune-aware treatment selection.
6 papers · 46.2%
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CDK4/6 Inhibitor Development
CDK4/6 inhibition is expanding beyond established breast cancer use into dedifferentiated liposarcoma, esophageal squamous cell carcinoma and meningioma. Palbociclib is being tested with retifanlimab, while subtype-specific vulnerabilities and immune-cell responses are defining new combination opportunities. Abemaciclib and palbociclib show divergent neuropsychiatric and systemic toxicity profiles, keeping comparative safety important. Drug-delivery platforms and microfluidic systems support efforts to improve exposure and model immune infiltration.
5 papers · 38.5%
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Others — Drug and Infection Research
Host-directed therapy for tuberculous meningitis uses ubenimex, imatinib and antibiotics across mouse and human models, while a separate study models pH-mediated drug interactions for formulation design. The shared thread is pharmacological optimization rather than one disease or mechanism. Evidence spans neuroinflammation, interferon responses and PBPK predictions. No single therapeutic direction unites the cluster.
2 papers · 15.4%
Papers
The 13 papers from the last 6 months that study palbociclib directly, newest first, by theme and by study type. Study types come from PubMed publication types and MeSH headings.
By theme
CDK4/6 Inhibition in Breast Cancer (6)
- Metastasis of triple negative breast cancer is regulated by a targetable miR-342-E2F network. EMBO molecular medicine · 21 Aug 2026 PMID 42629473
- Real-world treatment patterns and outcomes in hormone receptor-positive, HER2-low metastatic breast cancer, 2018-2023: a retrospective, observational, US cohort study. Breast cancer research and treatment · 20 Jul 2026 PMID 42474828
- Age, Age-Related Comorbidities and Survival in Palbociclib, Ribociclib and Abemaciclib Users With Advanced Breast Cancer: A Nation-Wide Retrospective Cohort Study. Pharmacoepidemiology and drug safety · 16 Jun 2026 PMID 42301003
- Real world experience with cyclin dependent kinase inhibitors in metastatic breast cancer in India. PloS one · 15 May 2026 PMID 42139194
- Safety and antitumour activity of ipatasertib combined with endocrine therapy and a CDK4/6 inhibitor in HR+/HER2- metastatic breast cancer (TAKTIC): a single-centre, open-label, phase 1b trial. The Lancet. Oncology · 30 Apr 2026 PMID 42061370
- CSF1R inhibitors mitigate CDK4/6 inhibitor-induced immunosuppression to increase antitumor immunity in HR+/HER2- breast cancer. Oncogene · 15 Apr 2026 PMID 41986650
CDK4/6 Inhibitor Development (5)
- CDK4/6 inhibition uncovers subtype-specific vulnerabilities and immune-related responses in esophageal squamous cell carcinoma. Cell death & disease · 29 May 2026 PMID 42215475
- Circular-by-Design Zwitterionic Polyglycerol-Polyoxazoline-Lysine Pseudodendrimers as Multifunctional Antibacterial and Anticancer Drug Delivery Platforms. Biomacromolecules · 7 May 2026 PMID 42095698
- Divergent neuropsychiatric and systemic toxicity profiles of abemaciclib and palbociclib: a triangulation study integrating pharmacovigilance, genetic epidemiology, and multi-omics profiling. Naunyn-Schmiedeberg's archives of pharmacology · 6 May 2026 PMID 42091703
- Phase 2 study of palbociclib plus retifanlimab in patients with advanced dedifferentiated liposarcoma. Journal for immunotherapy of cancer · 4 May 2026 PMID 42082272
- Next-Generation Therapies for Meningioma: Overcoming Barriers and Expanding Treatment Options. Cancer investigation · 22 Apr 2026 PMID 42017452
Others — Drug and Infection Research (2)
- Host-directed treatments for tuberculous meningitis utilizing a multi-platform approach across mouse and human models. Nature communications · 21 Jul 2026 PMID 42481504
- Mechanistic PBPK Modeling of pH-Modifying Excipient Effects to Guide Formulation Design for Mitigating pH-Mediated DDIs. Molecular pharmaceutics · 16 Jun 2026 PMID 42298946
By study type
Clinical trials (2)
- Phase 2 study of palbociclib plus retifanlimab in patients with advanced dedifferentiated liposarcoma. Journal for immunotherapy of cancer · 4 May 2026 PMID 42082272
- Safety and antitumour activity of ipatasertib combined with endocrine therapy and a CDK4/6 inhibitor in HR+/HER2- metastatic breast cancer (TAKTIC): a single-centre, open-label, phase 1b trial. The Lancet. Oncology · 30 Apr 2026 PMID 42061370
Observational studies and case reports (3)
- Real-world treatment patterns and outcomes in hormone receptor-positive, HER2-low metastatic breast cancer, 2018-2023: a retrospective, observational, US cohort study. Breast cancer research and treatment · 20 Jul 2026 PMID 42474828
- Age, Age-Related Comorbidities and Survival in Palbociclib, Ribociclib and Abemaciclib Users With Advanced Breast Cancer: A Nation-Wide Retrospective Cohort Study. Pharmacoepidemiology and drug safety · 16 Jun 2026 PMID 42301003
- Real world experience with cyclin dependent kinase inhibitors in metastatic breast cancer in India. PloS one · 15 May 2026 PMID 42139194
Human data, design not indexed (2)
- Mechanistic PBPK Modeling of pH-Modifying Excipient Effects to Guide Formulation Design for Mitigating pH-Mediated DDIs. Molecular pharmaceutics · 16 Jun 2026 PMID 42298946
- Circular-by-Design Zwitterionic Polyglycerol-Polyoxazoline-Lysine Pseudodendrimers as Multifunctional Antibacterial and Anticancer Drug Delivery Platforms. Biomacromolecules · 7 May 2026 PMID 42095698
Preclinical: animal, cell and lab studies (2)
- Host-directed treatments for tuberculous meningitis utilizing a multi-platform approach across mouse and human models. Nature communications · 21 Jul 2026 PMID 42481504
- CSF1R inhibitors mitigate CDK4/6 inhibitor-induced immunosuppression to increase antitumor immunity in HR+/HER2- breast cancer. Oncogene · 15 Apr 2026 PMID 41986650
Unclassified: not yet indexed with MeSH (4)
- Metastasis of triple negative breast cancer is regulated by a targetable miR-342-E2F network. EMBO molecular medicine · 21 Aug 2026 PMID 42629473
- CDK4/6 inhibition uncovers subtype-specific vulnerabilities and immune-related responses in esophageal squamous cell carcinoma. Cell death & disease · 29 May 2026 PMID 42215475
- Divergent neuropsychiatric and systemic toxicity profiles of abemaciclib and palbociclib: a triangulation study integrating pharmacovigilance, genetic epidemiology, and multi-omics profiling. Naunyn-Schmiedeberg's archives of pharmacology · 6 May 2026 PMID 42091703
- Next-Generation Therapies for Meningioma: Overcoming Barriers and Expanding Treatment Options. Cancer investigation · 22 Apr 2026 PMID 42017452
Written from 13 PubMed abstracts, each one listed by PMID above. Published: 2026-06-15. Last written: 2026-08-26 by GPT. Corrections: 2026-09-26 by GPT. Drafted by language models from published abstracts; not medical advice.