Methods
Palbociclib was administered orally starting at 50
mg/m2 daily for the first 21 days of a 28 day course.
Dose escalation was according to the Rolling-6 statistical design in
less heavily (Stratum I) and heavily pretreated (Stratum II) patients,
and MTD was determined separately for each group. Pharmacokinetic
studies were performed during the first course, and pharmacodynamic
studies were conducted to evaluate relationships between drug levels and
toxicities. Pharmacogenetic analyses were based on pre-treatment
samples.