Results:
DRUG INTERACTION
Following single-dose oral administration, giredestrant was rapidly absorbed and generally showed a dose-proportional increase in exposure at doses ranging from 10 to 250 mg. At the 30 mg clinical dose, maximum plasma concentration was 266 ng/mL (50.1%) and area under the concentration–time curve from 0 to 24 hours at steady state was 4,320 ng·hour/mL (59.4%). Minimal giredestrant concentrations were detected in urine, indicating that renal excretion is unlikely to be a major elimination route for giredestrant. Mean concentration of 4beta-hydroxycholesterol showed no apparent increase over time at both the clinical dose (30 mg) and a supratherapeutic dose (90 mg), suggesting that giredestrant may have low CYP3A induction potential in humans. No clinically relevant drug–drug interaction was observed between giredestrant and palbociclib. Giredestrant exposure was not affected by food and was generally consistent between White and Asian patients.