Advanced Physician Search: 1st Line

This is a Phase 3, open-label, randomized, clinical trial evaluating the efficacy and safety of gedatolisib and palbociclib plus endocrine therapy for the treatment of patients with locally advanced or metastatic HR+/HER2- advanced breast cancer.

Drug: Arm D: Ribociclib + Letrozole

A Phase Ib/III Open-label, Randomised Study of Capivasertib plus CDK4/6 Inhibitors and Fulvestrant versus CDK4/6 Inhibitors and Fulvestrant in Hormone Receptor-Positive and Human Epidermal Growth Factor Receptor 2-Negative Locally Advanced, Unresectable or Metastatic Breast Cancer (CAPItello-292)

Drug: Fulvestrant

This is a prospective study to assess the impact of biomarker driven, early therapeutic switching and delayed imaging with the incorporation of DiviTum® serum TK1 activity (DiviTum® TKa) in patients with HR positive, HER-2 negative metastatic or unresectable breast cancer. Patients will receive first-line treatment with a CDK4/6 inhibitor (CDK4/6i) and endocrine therapy. All patients will have blood drawn for thymidine kinase activity (TKa) testing at baseline and at C1D15. Patients who are found to have a lack of TKa suppression at C1D15 will be recommended to switch to an alternative therapy. Patients with suppressed C1D15 TKa levels will continue on CDK4/6i and endocrine therapy until clinical progression. Patients with TKa which remains suppressed will be recommended to delay restaging scans from 24 weeks to 36 weeks. The investigators hypothesize that a patient’s TKa level at C1D15 is prognostic for progression-free survival (PFS) on a CDK4/6 inhibitor and early therapeutic switching in patients with a lack of C1D15 TKa suppression will be associated with prolonged PFS.

Device: DiviTum® TKa assay, Drug: CDK4/6 + Endocrine therapy