Hoffmann-La Roche
This study will evaluate the efficacy and safety of inavolisib in combination with Phesgo (pertuzumab, trastuzumab, and rHuPH20 injection for subcutaneous use) compared with placebo in combination with Phesgo, as maintenance therapy, after induction therapy in participants with previously untreated HER2-positive advanced breast cancer (ABC).
Inclusion Criteria: * Eastern Cooperative Oncology Group (ECOG) Performance Status 0 or 1 * Histologically or cytologically confirmed and documented adenocarcinoma of the breast with metastatic or locally advanced disease not amenable to curative resection * Confirmation of HER2 biomarker eligibility based on valid results from central testing of tumor tissue documenting HER2-positivity * Confirmation of PIK3CA-mutation biomarker eligibility based on valid results from central testing of tumor tissue documenting PIK3CA-mutated tumor status * Disease-free interval from completion of adjuvant o…
Participants will receive an inavolisib tablet to be taken orally (PO), once a day (QD), on Days 1-21 of each 21-day cycle, beginning on Day (D) 1 of Cycle (C) 1 of maintenance treatment.
Phesgo will be administered to participants subcutaneously every 3 weeks (Q3W) on D1 of each 21-day cycle.
Inavolisib-matching tablet taken PO QD on Days 1-21 of each 21-day cycle, beginning on D1 C1 of maintenance treatment.
During the induction therapy phase, the investigator's choice of taxane-based chemotherapy will be administered after Phesgo.
Optional endocrine therapy (ET) is allowed at the discretion of the investigator, based on the standard of care. Allowed ETs are tamoxifen, or one of the specified third-generation aromatase inhibitor (AI \[anastrozole, letrozole, or exemestane\]), or fulvestrant. The investigator will determine and supply the appropriate luteinizing hormone-releasing hormone (LHRH) agonist locally approved for use in breast cancer. The LHRH agonist will be administered according to local prescribing information.