A Study of Trastuzumab Emtansine in Combination With Atezolizumab or Placebo as a Treatment for Participants With Human Epidermal Growth Factor 2 (HER2)-Positive and Programmed Death-ligand 1 (PD-L1)-Positive Locally Advanced (LABC) or Metastatic Breast Cancer (MBC)

Official Title

A Randomized, Multicentre, Double-Blind, Placebo-Controlled Phase III Study of the Efficacy and Safety of Trastuzumab Emtansine in Combination With Atezolizumab or Placebo in Patients With HER2-Positive and PD-L1-Positive Locally Advanced or Metastatic Breast Cancer Who Have Received Prior Trastuzumab- (+/- Pertuzumab) and Taxane-Based Therapy (KATE3)

Summary:

This study will evaluate the efficacy, safety and patient-reported outcomes of trastuzumab emtansine plus atezolizumab compared with trastuzumab emtansine plus placebo in participants with HER2-positive and PD-L1-positive LABC or MBC.Participants must have progressed either during or after prior trastuzumab- (+/- pertuzumab) and taxane-based therapy for LABC/MBC; or during (or within 6 months after completing) trastuzumab- (+/-pertuzumab) and taxane-based therapy in the neoadjuvant and/or adjuvant setting.

Trial Description

Primary Outcome:

• Progression-Free Survival (PFS) as Determined by Investigator's Assessment Using Response Evaluation Criteria in Solid Tumours (RECIST) Version 1.1 (v1.1)
• Overall Survival (OS)

• Percentage of Participants With Objective Response Rate (ORR) as Determined by Investigator's Assessment Using RECIST v1.1
• Duration of Objective Response (DOR) as Determined by Investigator Assessment Using RECIST v1.1
• PFS as Determined by a Blinded Independent Central Review Committee Using RECIST v1.1
• PFS in Participants with Baseline Brain Metastases as Determined by Investigator Assessment Using RECIST v1.1
• OS in Participants with Baseline Brain Metastases
• Central Nervous System (CNS) PFS as Determined by Investigator Assessment Using RECIST v1.1 in Participants with or Without Baseline CNS Metastases
• Mean Absolute Scores in Function (Physical, Role) and Global Health Status (GHS)/Quality of Life (QoL) as Measured by the European Organisation for Research and Treatment of Cancer (EORTC QLQ-C30)
• Mean Change-From-Baseline Scores in Function (Physical, Role) and GHS/QoL as Measured by the EORTC QLQ-C30
• Percentage of Participants with Clinically Meaningful Deterioration in GHS/QoL Physical, and Role Function as Measured by the EORTC QLQ-C30
• Percentage of Participants with Adverse Events (AEs) According to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) Version 5.0
• Maximum Serum Concentration (Cmax) of Trastuzumab Emtansine
• Cmax of Atezolizumab
• Percentage of Participants With Anti-Drug Antibodies (ADAs) to Trastuzumab Emtansine
• Percentage of Participants With ADAs to Atezolizumab

View this trial on ClinicalTrials.gov