Study of AZD2014 and Palbociclib in patients with Estrogen Receptor Positive (ER+) Metastatic Breast Cancer - PASTOR

This dose finding/extension study was designed originally to consist of three parts: Part A was intended to identify the MTD of the AZD2014/ palbociclib combination on a background of fulvestrant (referred to as the triplet) in postmenopausal women with locally advanced/ metastatic estrogen receptor positive (ER+) breast cancer. Part B was to further characterize safety, tolerability, PK, and preliminary efficacy in single-arm dose expansion groups. Part C was to be a Phase 2, randomized, double-blind, extension comparing the triplet and doublet combinations. Part C was deleted from the protocol and was not performed.

This dose finding/extension study was designed originally to consist of three parts: Part A is a Phase 1 triplet-dose finding investigation in 3-6 patients per cohort to determine the maximum tolerated dose (MTD) of the triplet. Part B is a single arm expansion in approximately 27 patients evaluable for response to define the recommended Phase 2 dose (RP2D). Part C was intended to investigate the efficacy of the triplet combination at the RP2D in a randomized, double-blind, placebo-controlled, stratified, parallel group extension. Part C was intended to include ER+, locally advanced and/or metastatic breast cancer patients who have progressed following prior non-steroidal aromatase inhibitor (NSAI) endocrine therapy. Patients in Part C were to be randomized to receive either the triplet combination (AZD2014 + palbociclib + fulvestrant) or the doublet (matching AZD2014 placebo + palbociclib + fulvestrant). Patients were to be stratified according to hormone sensitivity, presence of visceral metastases, and prior CDK inhibitor treatment. Part C would have been conducted if indicated by the emerging data.