Table 6.

Summary of trough plasma letrozole concentrations following multiple oral doses of palbociclib 125 mg and letrozole 2.5 mg once daily

Parameter (unit)	Predose plasma letrozole concentrations
	Letrozole alone	Palbociclib + letrozole
Geometric mean Ctrough (ng/mL)	146†	131‡
Geometric CV (%)	59†	53‡
Geometric mean ratio (palbociclib + letrozole/letrozole alone [part 2])	0.9

†Calculated by using arithmetic mean values for each patient on day 1 of cycles 2 and 3. ‡Calculated by using arithmetic mean values for each patient on day 15 of cycles 1 and 2. C_trough, trough plasma concentration; CV, coefficient of variation.