Last reviewed 2026-04-20 · How we verify

Palbociclib in combination with AI (palbociclib-in-combination-with-ai)

Palbociclib in combination with AI (generic name: palbociclib-in-combination-with-ai) is a CDK inhibitor drug developed by Pfizer. It is currently FDA-approved for Hormone receptor-positive, human epidermal growth factor receptor 2-negative (HER2-negative) advanced or metastatic breast cancer in combination with an aromatase inhibitor as initial endocrine-based therapy in postmenopausal women with estrogen receptor-positive (ER+), HER2-negative breast cancer, Hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-negative) advanced or metastatic breast cancer in combination with fulvestrant in women with disease progression following endocrine therapy.

Palbociclib is a CDK4/6 inhibitor used in combination with aromatase inhibitors or fulvestrant for hormone receptor-positive, HER2-negative breast cancer. It is marketed by Pfizer Inc. and has generated $21.2B in revenue. The drug's mechanism involves targeting CDK4/6 to inhibit cell cycle progression. This leads to a decrease in tumor growth and proliferation. Palbociclib has shown clinical differentiation in combination with endocrine therapies. Its commercial significance lies in its ability to improve patient outcomes and increase treatment options. Pipeline developments are ongoing to explore its potential in other indications.

At a glance

Approved indications

• Hormone receptor-positive, human epidermal growth factor receptor 2-negative (HER2-negative) advanced or metastatic breast cancer in combination with an aromatase inhibitor as initial endocrine-based therapy in postmenopausal women with estrogen receptor-positive (ER+), HER2-negative breast cancer
• Hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-negative) advanced or metastatic breast cancer in combination with fulvestrant in women with disease progression following endocrine therapy

Common side effects

• Neutropenia
• Neutrophils decreased
• Leukopenia
• White blood cell count decreased
• Hemoglobin decreased
• Anemia
• Platelets decreased
• Thrombocytopenia
• Infections
• Fatigue
• Nausea
• Diarrhea

Serious adverse events

• Neutropenia
• Alanine aminotransferase increase

Drug interactions

• CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, clarithromycin, atazanavir, indinavir, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, voriconazole)
• CYP3A4 inducers (e.g., rifampicin, phenytoin, carbamazepine, phenobarbital, enzalutamide, St. John's Wort)
• Strong CYP3A4 inhibitors (e.g., atazanavir, indinavir, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, voriconazole)
• Moderate CYP3A4 inhibitors (e.g., amprenavir, aprepitant, fosamprenavir, fosaprepitant, tipranavir)
• CYP3A4 substrates (e.g., alfentanil, cyclosporine, fentanyl, sirolimus, tacrolimus)
• Warfarin
• Tamoxifen
• Lactation

Key clinical trials

• Targeted Therapy Directed by Genetic Testing in Treating Patients With Locally Advanced or Advanced Solid Tumors, The ComboMATCH Screening Trial (PHASE2)
• The CDK4/6 Inhibitor Dosing Knowledge (CDK) Study (PHASE3)
• TREATMENT AND MONITORING PATTERNS AND CLINICAL OUTCOMES IN PATIENTS RECEIVING PALBOCICLIB COMBINATION TREATMENT (WITH AI OR FULVESTRANT) FOR HR+/HER2- A/MBC IN A COMMUNITY ONCOLOGY SETTING.
• Evaluation of Lasofoxifene Combined With Abemaciclib Compared With Fulvestrant Combined With Abemaciclib in Locally Advanced or Metastatic ER+/HER2- Breast Cancer With an ESR1 Mutation (PHASE3)
• Levels of Circulating Tumor DNA as a Predictive Marker for Early Switch in Treatment for Patients With Metastatic (Stage IV) Breast Cancer (PHASE2)
• Swedish Ibrance Registries Insights (SIRI)
• A Real-life Study to Understand the Use and Effects of Palbociclib in US Patients With Breast Cancer
• Study to Compare Overall Survival in Medicare Patients With Metastatic Breast Cancer Treated With a Medicine Called Palbociclib in Combination With Aromatase Inhibitor and Aromatase Inhibitor by Itself.

Primary sources

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Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Palbociclib in combination with AI CI brief — competitive landscape report
• Palbociclib in combination with AI updates RSS · CI watch RSS
• Pfizer portfolio CI

Frequently asked questions about Palbociclib in combination with AI

Related

• Drug class: All CDK inhibitor drugs
• Target: All drugs targeting CDK4/6
• Manufacturer: Pfizer — full pipeline
• Therapeutic area: All drugs in Oncology
• Indication: Drugs for Hormone receptor-positive, human epidermal growth factor receptor 2-negative (HER2-negative) advanced or metastatic breast cancer in combination with an aromatase inhibitor as initial endocrine-based therapy in postmenopausal women with estrogen receptor-positive (ER+), HER2-negative breast cancer
• Indication: Drugs for Hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-negative) advanced or metastatic breast cancer in combination with fulvestrant in women with disease progression following endocrine therapy
• Compare: Palbociclib in combination with AI vs similar drugs
• Pricing: Palbociclib in combination with AI cost, discount & access