A Study Evaluating the Efficacy and Safety of Inavolisib Plus Fulvestrant Compared With Alpelisib Plus Fulvestrant in Participants With HR-Positive, HER2-Negative, PIK3CA Mutated, Locally Advanced or Metastatic Breast Cancer Post CDK4/6i and Endocrine Combination Therapy

The drug-drug interaction (DDI) substudy will evaluate the impact of repeat doses of inavolisib (coadministered with fulvestrant) on single-dose pharmacokinetics of sensitive CYP450 enzyme substrates (midazolam, omeprazole and bupropion) in participants with hormone receptor (HR)-positive, HER2-negative, PIK3CA-mutated, locally advanced (LA) or metastatic breast cancer (mBC), who progressed during or after CDK4/6 inhibitor (CDK4/6i) in combination with endocrine therapy (ET). Enrollment for the substudy is now open to recruitment.