A Study of ZW25 (Zanidatamab) With Palbociclib Plus Fulvestrant in Patients With HER2+/HR+ Advanced Breast Cancer

  • End date
    Jun 30, 2023
  • participants needed
  • sponsor
    Zymeworks Inc.
Updated on 10 May 2022


This is a multicenter, Phase 2a, open-label, 2-part study to investigate the safety, tolerability, and anti-tumor activity of ZW25 (zanidatamab) in combination with palbociclib plus fulvestrant. Eligible patients include those with locally advanced (unresectable) and/or metastatic human epidermal growth factor receptor 2 (HER2)-positive, hormone receptor (HR)-positive breast cancer.


Part 1 of the study will first evaluate the safety and tolerability of ZW25 in combination with palbociclib plus fulvestrant and will confirm the recommended doses (RDs) of ZW25 and palbociclib in this combination. Part 2 of the study will evaluate the anti-tumor activity of the combination of ZW25 with palbociclib plus fulvestrant at the RD level in patients with HER2-positive, HR-positive advanced breast cancer.

Condition HER2+/HR+ Breast Cancer
Treatment fulvestrant, Palbociclib, ZW25, ZW25 (Zanidatamab)
Clinical Study IdentifierNCT04224272
SponsorZymeworks Inc.
Last Modified on10 May 2022


Yes No Not Sure

Inclusion Criteria

Pathologically-confirmed diagnosis of breast cancer with evidence of locally advanced (unresectable) and/or metastatic disease. All patients in both Parts 1 and 2 must have HER2-positive and HR-positive disease
Received prior treatment with trastuzumab, pertuzumab, AND ado-trastuzumab emtansine (T-DM1); disease progression during or after the most recent prior therapy. Patients in any part of the study who did not receive pertuzumab or T-DM1 because of lack of access (e.g., due to insurance coverage or because they were treated prior to regulatory agency approval of the agent in a relevant indication) or due to medical ineligibility for treatment with T-DM1 (e.g., history of severe infusion reactions to trastuzumab, >/= Grade 2 peripheral neuropathy, or platelet count < 100 x 10^9/L) may be eligible for the study. Prior treatment with endocrine therapy in the neoadjuvant, adjuvant, and/or metastatic setting is permitted
Sites of disease assessible per RECIST version 1.1 (both measurable and non-measurable disease allowed)
An Eastern Cooperative Oncology Group (ECOG) Performance Status score of 0 or 1
Adequate organ function
Adequate cardiac left ventricular function, as defined by left ventricular ejection fraction (LVEF) >/= institutional standard of normal

Exclusion Criteria

Prior treatment with trastuzumab, pertuzumab, lapatinib, T-DM1, or other anti-HER2-targeted therapy </= 3 weeks before the first dose of ZW25
Prior treatment with chemotherapy, other anti-cancer therapy not otherwise specified, or hormonal cancer therapy </= 3 weeks before the first dose of ZW25
Prior treatment with palbociclib or any other CDK4/6 inhibitor, including experimental agents
History of myocardial infarction or unstable angina within 6 months prior to enrollment, troponin levels consistent with myocardial infarction, or clinically significant cardiac disease, such as ventricular arrhythmia requiring therapy, uncontrolled hypertension, or any history of symptomatic congestive heart failure (CHF)
QTc Fridericia (QTcF) > 470 ms
Grade 2 or greater pneumonitis and/or interstitial lung disease, including pulmonary fibrosis, or other clinically significant infiltrative pulmonary disease not related to lung metastases
Active hepatitis B or hepatitis C infection
Acute or chronic uncontrolled renal disease, pancreatitis, or severe liver disease (Child-Pugh Class C)
Known infection with Human Immunodeficiency Virus (HIV)-1 or HIV-2 (Exception: patients with well controlled-HIV [e.g., cluster of differentiation 4 (CD4)-positive T-cell count > 350 mm3 and undetectable viral load] are eligible.)
Prior or concurrent malignancy whose natural history or treatment has the potential to interfere with the safety or efficacy assessment of the investigational regimen
Brain metastases: Untreated central nervous system (CNS) metastases, symptomatic CNS metastases, or radiation treatment for CNS metastases within 4 weeks of start of study treatment. Stable, treated brain metastases are allowed (defined as patients who are off steroids and anticonvulsants and are neurologically stable for at least 1 month at the time of screening)
History of or ongoing leptomeningeal disease
Grade 3 or greater peripheral neuropathy
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