A Study Of Oral Palbociclib (PD-0332991), A CDK4/6 Inhibitor, As Single Agent In Japanese Patients With Advanced Solid Tumors Or In Combination With Letrozole For The First-Line Treatment Of Postmenopausal Japanese Patients With ER (+) HER2 (-) Advanced Breast Cancer

PD-0332991 (100 mg or 125 mg) will be orally administered once a day for 3 weeks followed by 1 week off treatment, in the morning on an empty stomach. Dose reduction of PD-0332991 by one (100 mg) or two (75 mg) dose level is permitted depending on treatment related toxicity.

PD-0332991, 125 mg, will be orally administered with food once a day for 3 weeks followed by 1 week off treatment. PD-0332991 will be administered once a day together with letrozole. Dose reduction of PD-0332991 by one (100 mg) or two (75 mg) dose level is permitted depending on treatment related toxicity.

Letrozole, 2.5 mg, will be orally administered once a day in continuous daily dosing together with PD-0332991. Dose reduction of letrozole is not permitted, but dosing interruptions for letrozole-related toxicity are allowed as per investigator's medical judgement.

PD-0332991, 125 mg, will be orally administered with food once a day for 3 weeks followed by 1 week off treatment. PD-0332991 will be administered once a day together with letrozole. Dose reduction of PD-0332991 by one (100 mg) or two (75 mg) dose level is permitted depending on treatment related toxicity.

Letrozole, 2.5 mg, will be orally administered once a day in continuous daily dosing together with PD-0332991. Dose reduction of letrozole is not permitted, but dosing interruptions for letrozole-related toxicity are allowed as per investigator's medical judgement.