Palbociclib
Palbociclib is a targeted cancer therapy that inhibits cyclin-dependent kinases 4 and 6 (CDK4/6), which are proteins that drive cancer cell division. It is primarily used to treat HR-positive, HER2-negative advanced or metastatic breast cancer in combination with hormonal therapy. By blocking these kinases, the medication slows tumor growth and progression.
Palbociclib is a CDK4/6 inhibitor used with hormonal therapy to treat certain types of advanced breast cancer by slowing cancer cell division.
Key facts at a glance
- ATC
- L01EF01
- RxNorm
- 1601374
- Generic
- Palbociclib
- Class
- atc-l01
- Brands
- Ibrance
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- capsule, tablet
- Regions
- US, EU, CN, JP
- Monitoring
- —
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Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Palbociclib is indicated for the treatment of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced or metastatic breast cancer. It is typically used in combination with an aromatase inhibitor as first-line therapy for postmenopausal women, or with fulvestrant for patients who have progressed on prior hormonal therapy.
Palbociclib works by inhibiting cyclin-dependent kinases 4 and 6 (CDK4/6), which are enzymes that regulate the cell cycle and promote cancer cell proliferation. By blocking these kinases, the medication prevents uncontrolled cell division and can induce cell cycle arrest, slowing tumor growth.
Palbociclib is taken orally in scheduled cycles. Common side effects include neutropenia (low white blood cell count), fatigue, and nausea. Regular blood monitoring is required during treatment. It should not be used during pregnancy as it may harm the fetus. The medication may interact with other drugs that affect CYP3A4 enzymes.
Official drug label
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This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy