IBRANCE
Pronunciation: pal-boe-SYE-klib (EYE-brans)

What it isCDK4/6 inhibitor blocking cell cycle progression; hormone receptor-positive HER2-negative breast cancer.
Why this oneUnlike abemaciclib, it uses interrupted treatment and is limited by neutropenia rather than diarrhea.
What limits itNeutropenia governs treatment holds, though it rarely causes infection. CYP3A4 interactions can markedly alter exposure.
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| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| HR+/HER2- advanced/metastatic breast cancer (+ endocrine therapy) | Adults | 125 mg QD, 21 days on / 7 days off (28-day cycle) | 125 mg QD | 125 mg QD |
Renal No adjustment for CrCl >15 mL/min (mild-severe)
Hepatic No adjustment for mild-moderate (Child-Pugh A/B); severe (Child-Pugh C): 75 mg QD
Available strengths
Pregnancy Can cause fetal harm based on mechanism and animal findings
Lactation No data; do not breastfeed during treatment and for 3 weeks after last dose
| Strength | #/mo | generic $/mo | CostPlus | |
|---|---|---|---|---|
| 75 mg | tab | 30 qd | not offered | |
| 100 mg | tab | 30 qd | not offered | |
| 125 mg | tab | 30 qd | not offered | |
| 75 mg | cap | 30 qd | not offered | |
| 100 mg | cap | 30 qd | not offered | |
| 125 mg | cap | 30 qd | not offered |
Generic entry2036 est.
NO BOXED WARNINGS
Principal riskNeutropenia, which governs dosing
Legacy pregnancy categoryUnknown / historical label unavailable
Defining liabilityMyelosuppression and agent-specific hepatic, cardiac, pulmonary, neurologic or reproductive toxicity require oncology monitoring.