Table 2.

Monitoring Parameters for CDK4/6 Inhibitors

Drug	Dose and Schedule	Pregnancy Testa	CBC and Differential	Liver Tests (AST, ALT, and Total Bilirubin)	Serum Electrolytes (K, Ca, Mg, Phos)	ECG
Palbociclib	125 mg daily, 3 wk on, 1 wk off	Baseline	Baseline, every 2 wk for 2 mo, monthly for first 6 mo, then every 3 mod	NA	NA	NA
Ribociclib	600 mg daily, 3 wk on, 1 wk off	Baseline	Baseline, every 2 wk for 2 mo, monthly for 4 mo	Baseline, every 2 wk for 2 mo, monthly for 4 mo	Baseline, monthly for 6 mo	Baseline, day 14 of cycle 1, day 1 of cycle 2
Abemaciclib	150 mg twice dailyb OR 200 mg twice dailyc	Baseline	Baseline, every 2 wk for 2 mo, monthly for 2 mo	Baseline, every 2 wk for 2 mo, monthly for 2 mo	NA	NA

^a[In women of childbearing potential. Authors: please provide explanatory footnote (see “Pregnancy Test” column header).]

^bWhen given with fulvestrant.

^cWhen given alone.

^dIf no more than grade 1 or 2 neutropenia in the first 6 months

ALT = alanine aminotransferase; AST = aspartate aminotransferase; CBC = complete blood count; ECG = electrocardiogram; NA = not applicable