- HR-positive, HER2-negative advanced or metastatic breast cancer, in combination with:
- Letrozole (first-line in postmenopausal women)
- Fulvestrant (after progression following endocrine therapy)
Dosage:
- 125 mg orally once daily for 21 consecutive days, followed by 7 days off (28-day cycle)
- Used in combination with letrozole or fulvestrant
- Capsules: 75 mg, 100 mg, 125 mg
- Tablets (Ibrance®): same strengths; interchangeable with capsules but do not substitute milligram-for-milligram
- Take with food, preferably at the same time each day
- Swallow whole – do not crush, chew, or split
- If a dose is missed, do not take an extra dose; take the next dose at the scheduled time
- Class: CDK4/6 inhibitor
- Mechanism of Action:
Inhibits cyclin-dependent kinases 4 and 6 (CDK4/6), which blocks phosphorylation of the retinoblastoma (Rb) protein, resulting in G1 phase cell cycle arrest in cancer cells. - Metabolism: Liver (mainly via CYP3A4)
- Half-life: ~29 hours
- Excretion: Feces (~74%), urine (~17%)
- Neutropenia, leukopenia
- Fatigue
- Nausea, diarrhea
- Stomatitis
- Alopecia
- Infections (e.g., URTI)
- Hypersensitivity to palbociclib or any excipients
- Coadministration with strong CYP3A inhibitors or inducers, unless benefit outweighs risk
- CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): ↑ palbociclib levels
- CYP3A4 inducers (e.g., rifampin, phenytoin): ↓ efficacy
- Avoid grapefruit or grapefruit juice
Drug Status
Availability | |
Pregnancy | |
Breastfeeding | |
Schedule |
BRAND NAME | STRENGTH | FORMULATION | PACK SIZE | MANUFACTURER | DISTRIBUTOR |
---|---|---|---|---|---|
Ibrance | 100mg | Capsule | 21’s | Pfizer Labs | Pfizer Labs |
Ibrance | 75mg | Capsule | 21’s | Pfizer Labs | Pfizer Labs |
Ibrance | 125mg | Capsule | 21’s | Pfizer Labs | Pfizer Labs |