Investigating Safety, Tolerability and Efficacy of AZD5363 When Combined With Paclitaxel in Breast Cancer Patients

This is a Phase I/II multicentre, study investigating the safety, tolerability and efficacy of a twice-daily oral formulation of AZD5363 when combined with a weekly intravenous paclitaxel infusion in patients with advanced or metastatic breast cancer. Study treatment is given in 28-day cycles, comprising three weeks on-therapy followed by one week off-therapy. The study will be conducted in two parts: Part A. Approximately 40 patients will be recruited to this Phase I multiple ascending-dose safety run-in evaluation of each of two intermittent dosing schedules (2 days per week or 4 days per week) of AZD5363 given in combination with weekly paclitaxel. The study population is female patients, 18 years or older, with advanced or metastatic breast cancer. The purpose of Part A is to assess the comparative safety, tolerability, pharmacokinetics and preliminary efficacy of both schedules to determine one dose and schedule of AZD5363 to take forward to study Part B in combination with weekly paclitaxel. Part A assessments will be made in dose-escalating cohorts of 3 to 6 patients to determine a recommended dose in each of the schedules. A total of 6 patients must be evaluated at a selected dose level for it to be confirmed as the recommended dose. All dose evaluations and recommendations will be conducted by a Safety Review Committee. Part A Patients will undergo assessments up to to withdrawal from the study or to discontinuation of study therapy. Part B. A minimum of 100 patients will be recruited to this Phase II double-blind, placebo-controlled, stratified and randomised evaluation of two treatment regimens: AZD5363 (at a dose selected and schedule from Part A) in combination with weekly paclitaxel vs. weekly paclitaxel plus placebo. The study population is female patients with Estrogen Receptor Positive advanced or metastatic breast cancer; of which approximately 50 will have the phosphoinositide-3-kinase, catalytic, alpha polypeptide (PIK3CA) mutation. Part B patients will be stratified by PIK3CA tumour mutation status as: tumour mutation positive or tumour mutation not-detected. Under each stratum patients will be randomised to receive either paclitaxel + AZD5363 or paclitaxel + placebo. The purpose of Part B is to assess relative efficacy of both active and placebo regimens by comparison of: progression-free survival, overall survival, tumour response, safety and tolerability in the overall ER+ve advanced or metastatic breast cancer population, and in a subgroup of these patients with the PIK3CA tumour mutation. Patient safety and therapy tolerability will be monitored by an independent Safety Review Committee throuighout the course of Part B. Part B patients will be followed for assessment of overall survival, or to withdrawal from the study.