This study will investigate whether concurrent administration of rabeprazole, an antacid known as a proton pump inhibitor, alters the absorption of the drug palbociclib when given as one of six experimental formulations.

This will be a 6 cohort study investigating one experimental formulation of palbociclib in each of the six cohorts of 10 healthy subjects. Each cohort will receive two treatments in a fixed-sequence. In Period 1, all subjects will receive a single 125mg dose of palbociclib alone and undergo serial pharmacokinetic blood sampling for up to 120 hours post-dose. In Period 2, all subjects will receive daily 40mg doses of Rabeprazole for 7 consecutive days, and approximately 4 hours after the Day 7 rabeprazole dose each subject will receive a single 125mg dose of palbociclib. Subjects will undergo serial pharmacokinetic blood sampling up to 120 hours post-dose.

Inclusion Criteria:

• Healthy Male or Female of non-childbearing potential,
• Having a body weight >50 kg
• Having a bopy mass index (BMI) between 17.5 and 30.5 kg/m2.

Exclusion Criteria:

• Any condition possibly affecting drug absorption (eg, gastrectomy)
• A positive urine drug or cotinine test
• A known history of hypersensitivity to palbociclib
• A supine systolic blood pressure >140 mmHg, or a QTc >450 msec.