A Study of Tucatinib or Placebo With Trastuzumab and Pertuzumab for Metastatic HER2+ Breast Cancer

Official Title

A Randomized, Double-blind, Phase 3 Study of Tucatinib or Placebo in Combination With Trastuzumab and Pertuzumab as Maintenance Therapy for Metastatic HER2+ Breast Cancer (HER2CLIMB-05)


This study is being done to see if tucatinib works better than placebo when given with other drugs to treat participants with HER2-positive breast cancer. A placebo is a pill that looks the same as tucatinib but has no medicine in it. This study will also test what side effects happen when participants take this combination of drugs. A side effect is anything a drug does to the body besides treating your disease. Participants will have cancer that has spread in the body near where it started (locally advanced) and cannot be removed (unresectable) or has spread through the body (metastatic). In this study, all participants will get either tucatinib or placebo. Participants will be assigned randomly to a group. This is a blinded study, so patients and their doctors will not know which group a participant is in. All participants will also get trastuzumab and pertuzumab. These are 2 drugs used to treat this type of cancer.

Trial Description

Primary Outcome:

  • Progression-free survival (PFS) by investigator assessment per Response Evaluation Criteria in Solid Tumours (RECIST) v1.1
Secondary Outcome:
  • Overall survival (OS)
  • PFS by blinded independent central review (BICR) per RECIST v1.1
  • Time to deterioration of health-related quality of life (HRQoL)
  • Central nervous system (CNS) PFS
  • Incidence of adverse events (AEs)
  • Incidence of laboratory abnormalities
  • Incidence of tucatinib dose alterations
  • Incidence of trastuzumab dose alterations
  • Incidence of pertuzumab dose alterations
  • Maximum concentration (Cmax)
  • Trough concentration (Ctrough)
Control arm: Placebo given orally twice daily plus trastuzumab and pertuzumab every 21 days Experimental arm: Tucatinib 300 mg given orally twice daily plus trastuzumab and pertuzumab every 21 days Trastuzumab and pertuzumab will be administered as follows: • Trastuzumab will be given intravenously (IV) at a dose of 6 mg/kg or subcutaneously (SC) at a fixed dose of 600 mg, once every 21 days. AND Pertuzumab will be given IV at 420 mg every 21 days. OR Fixed dose combination of 600 mg pertuzumab, 600 mg trastuzumab, and 20,000 units hyaluronidase will be given SC, once every 21 days, in lieu of trastuzumab and pertuzumab individually.

View this trial on ClinicalTrials.gov

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Canadian Cancer Society

These resources are provided in partnership with the Canadian Cancer Society