Ribociclib

KISQALI

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What it isCDK4/6 inhibitor; hormone receptor-positive HER2-negative breast cancer.

Why this oneIt is the CDK4/6 inhibitor with the clearest overall survival benefit in first-line advanced disease.

What limits itQT prolongation requiring ECG monitoring, and neutropenia. CYP3A4-dependent.

FDA-approved for

HR-positive/HER2-negative breast cancer (2017)

FDA label

Read the full label on DailyMed ↗

FDA dosing	Population	Start	Target	Max
HR+/HER2- early breast cancer, adjuvant (w/ aromatase inhibitor)	adult	400 mg QD, 21 days on / 7 off	400 mg QD, 21 days on / 7 off	400 mg QD
HR+/HER2- advanced or metastatic breast cancer (w/ aromatase inhibitor or fulvestrant)	adult	600 mg QD, 21 days on / 7 off	600 mg QD, 21 days on / 7 off	600 mg QD

Renal Mild-moderate: no adjustment; severe: reduce starting dose to 200 mg

Hepatic Mild (Child-Pugh A): no adjustment; moderate-severe (B/C) in advanced disease: start 400 mg (no adjustment for early breast cancer)

Given in 28-day cycles: 21 days on, 7 days off

Instructions

Swallow whole; do not chew, crush, or split; do not take broken/cracked tablets
With or without food, same time each day (preferably morning)
Pre/perimenopausal women and men: add an LHRH agonist
Missed or vomited dose: skip, take next dose at usual time
Strong CYP3A inhibitor: avoid; if unavoidable reduce to 200 mg (early) or 400 mg (advanced)

Cautions

Interstitial lung disease/pneumonitis (can be fatal); interrupt and evaluate new respiratory symptoms
Severe cutaneous adverse reactions (SJS, TEN, DRESS); discontinue if confirmed
QT interval prolongation (concentration-dependent); monitor ECG and electrolytes; avoid QT-prolonging drugs and strong CYP3A inhibitors
Not for concomitant use with tamoxifen (increased QT prolongation)
Hepatotoxicity; monitor LFTs
Neutropenia; monitor CBC
Embryo-fetal toxicity

Adverse reactions

Neutropenia/leukopenia
Anemia
Lymphopenia
Increased AST/ALT/GGT
Increased creatinine
Infections
Nausea/vomiting
Diarrhea
Fatigue
Thrombocytopenia
Headache
Alopecia
Rash

Pregnancy Can cause fetal harm (animal embryo-fetal toxicity); no human data; effective contraception during and ≥3 weeks after last dose

Lactation Do not breastfeed during and for at least 3 weeks after the last dose

NO BOXED WARNINGS

Principal riskQT prolongation needing ECG monitoring

Cost, est. cash$5,000–$30,000+/month or cycle

Generic entry2036 est.

Classes and tags

Clinical profile

Therapeutic safety burden3 / 4

Overdose danger2 / 4

Weight-gain liability0 / 4

Sedation liability0 / 4

QT / Torsades3 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk3 / 4

Legacy pregnancy categoryNot assigned — PLLR-era drug

Defining liabilityMyelosuppression and agent-specific hepatic, cardiac, pulmonary, neurologic or reproductive toxicity require oncology monitoring.