Study of Pembrolizumab (MK-3475) Plus Chemotherapy vs. Placebo Plus Chemotherapy for Previously Untreated Locally Recurrent Inoperable or Metastatic Triple Negative Breast Cancer (MK-3475-355/KEYNOTE-355)

Official Title

A Randomized, Double-Blind, Phase III Study of Pembrolizumab (MK-3475) Plus Chemotherapy vs Placebo Plus Chemotherapy for Previously Untreated Locally Recurrent Inoperable or Metastatic Triple Negative Breast Cancer - (KEYNOTE-355)

Summary:

The study will consist of two parts. In Part 1, the safety of pembrolizumab (MK-3475) in combination with one of three different chemotherapies will be assessed in the treatment of locally recurrent inoperable or metastatic triple negative breast cancer (TNBC), which has not been previously treated with chemotherapy. In Part 2, the safety and efficacy of pembrolizumab plus chemotherapy will be assessed compared to the safety and efficacy of placebo plus chemotherapy in the treatment of locally recurrent inoperable or metastatic TNBC, which has not been previously treated with chemotherapy. The primary hypotheses are that the combination of pembrolizumab and chemotherapy prolongs Progression-Free Survival (PFS) compared to placebo and chemotherapy in all participants and in participants with programmed cell death ligand 1 (PD-L1) positive tumours, and prolongs Overall Survival (OS) compared to placebo and chemotherapy in all participants and in participants with PD-L1 positive tumours.

Trial Description

Primary Outcome:

  • Part 1: Percentage of Participants Who Experience an Adverse Event (AE)
  • Part 1: Percentage of Participants Who Discontinue Study Drug Due to an AE
  • Part 2: Progression-Free Survival (PFS) - All Participants
  • Part 2: PFS - Participants With PD-L1 Positive Tumours
  • Part 2: Overall Survival (OS) - All Participants
  • Part 2: OS - Participants With PD-L1 Positive Tumours
Secondary Outcome:
  • Part 2: Objective Response Rate (ORR) - All Participants
  • Part 2: ORR - Participants With PD-L1 Positive Tumours
  • Part 2: Duration of Response (DOR) - All Participants
  • Part 2: DOR - Participants With PD-L1 Positive Tumours
  • Part 2: Disease Control Rate (DCR) - All Participants
  • Part 2: DCR - Participants With PD-L1 Positive Tumours
  • Part 2: Percentage of Participants Who Experience an AE
  • Part 2: Percentage of Participants Who Discontinue Study Drug Due to an AE

View this trial on ClinicalTrials.gov

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Resources

Canadian Cancer Society

These resources are provided in partnership with the Canadian Cancer Society