A Phase 2 interventional study of Zanidatamab and Paclitaxel in HER2-positive Breast Cancer and Breast Cancer, sponsored by Jazz Pharmaceuticals. Recruiting at 53 sites in 4 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-29.
Sponsored by Jazz Pharmaceuticals · Phase 2, Interventional, and Treatment
The purpose of this study is to see if zanidatamab is safe and effective, when combined with chemotherapy, in treating people who has Human Epidermal Growth Factor Receptor 2 (HER2)-positive, early-stage breast cancer
14,825 studies on the registry are indexed under Breast Neoplasms; 3,319 are open to participants now.
This study's planned enrollment of 125 is above the median of 72 across 10,896 interventional studies indexed under Breast Neoplasms.
Browse Breast Neoplasms studies →Jazz Pharmaceuticals is the lead sponsor of 173 studies on the registry; 18 are open to participants now.
Of its 42 completed or terminated interventional studies of FDA-regulated products, 32 (76%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Participants with known are eligible unless:
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.
In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.
Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
The number of CD4 cells, a type of white blood cell, in a given amount of blood. It is used to follow how well the immune system is doing in HIV.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
Histologically or cytologically confirmed
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HER2
HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.
In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adjuvant and neoadjuvant
Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
LVEF (left ventricular ejection fraction)
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CD4 count
The number of CD4 cells, a type of white blood cell, in a given amount of blood. It is used to follow how well the immune system is doing in HIV.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Excipients
The other ingredients in a medicine besides the active drug, such as fillers, colours or preservatives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Live vaccines
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Zanidatamab in combination with chemotherapy paclitaxel
Drug: Zanidatamab · Drug: Paclitaxel
Zanidatamab in combination with chemotherapy docetaxel and carboplatin
Drug: Zanidatamab · Drug: Docetaxel · Drug: Carboplatin
Trastuzumab and pertuzumab in combination with chemotherapy docetaxel and carboplatin
Drug: Docetaxel · Drug: Carboplatin · Drug: Trastuzumab · Drug: Pertuzumab
Administered intravenously (IV)
Also known as: ZW25, JZP598, ZIIHERA®
Administered intravenously (IV)
Administered intravenously (IV)
Administered intravenously (IV)
Administered intravenously (IV)
Administered intravenously (IV)
Number of participants with pCR
Pathologic complete response (pCR) is defined as lacking all signs of cancer in the tissue samples removed in the breast or axilla (armpit) during surgery or biopsy after study treatment
Time frame: Up to 8 months
Number of participants with Pathologic response by Residual Cancer Burden (RCB) classification
Time frame: Up to 8 months
Number of Participants with Treatment-emergent Adverse Events (TEAEs)
Time frame: Up to 23 months
Number of Participants Discontinuing Study Treatment Due to TEAEs
Time frame: Up to 23 months
Number of participants that completed breast conservation surgery (BCS)
Time frame: Up to 8 months
Event Free Survival (EFS)
EFS is defined as the time (in months) from randomization to disease progression, disease recurrence, second primary invasive cancer (non-breast) or death from any cause
Time frame: Up to 46 months
Overall Survival (OS)
OS is defined as the time in months from randomization to the date of death due to any cause.
Time frame: Up to 46 months
Number of participants reporting Symptomatic Adverse Events based on Patient-reported Outcome-Common Terminology Criteria for AEs (PRO-CTCAE)
Symptomatic AEs assessed by the PRO-CTCAE are analyzed at the item level with symptom severity, frequency, and interference scored from 0 to 4 and presence/absence scored 0 to 1, and higher scores reflect worse symptoms.
Time frame: Up to 23 months
Number of participants reporting Symptomatic Adverse Events based on European Organisation for Research and Treatment of Cancer (EORTC) Item Library
Symptomatic AEs assessed by the EORTC Item Library Forms are analyzed at the item level with scores ranging from 1 to 4, where a 4 indicates more severe symptoms.
Time frame: Up to 23 months
Percentage of all treated participants reporting overall side-effect bother on the Functional Assessment of Chronic Illness Therapy General Physical Item 5 (FACIT-GP5)
The Functional Assessment of Chronic Illness Therapy (FACIT) GP5 Item score ranges from 0 (Not at all) to 4 (Very Much), where higher scores reflect greater bother from treatment side effects.
Time frame: Up to 23 months
Serum Concentrations of Zanidatamab
Time frame: Up to 18 months
Number of Participants Positive for Anti-drug Antibodies to Zanidatamab
Time frame: Up to 18 months
Plan to share: Yes — In accordance with ICMJE requirements, Jazz Pharmaceuticals may provide qualified external researchers access to individual participant data (IPD) and clinical trial data that underlie the results of this trial upon request. Qualified researchers can submit a request on https://www.jazzpharma.com/science/clinical-trial-data-sharing/ as outlined. Jazz Pharmaceuticals reserves the right not to consider a request. For inquiries about Jazz's data sharing policy contact clinicaldatasharing@jazzpharma.com.
Data sharing details ↗ · www.jazzpharma.com
No publications or documents are linked to this record.
Started Sep 2025 (actual). Primary completion is estimated for Dec 2027, 27 months after the start.
Of 232 industry-sponsored phase 2 interventional studies under Breast Neoplasms, half reached primary completion within 34 months of starting (the median), counting those still running; a quarter within 22 and three quarters within 53. This study's planned 27 months is below that.
Counting every sponsor, half of 1,302 studies reached it within 51 months; a quarter within 30 and three quarters within 82.
Since we started tracking on Sep 25, 2026, the dates moved once, on Oct 29, 2026: primary completion Jan 2028 → Dec 2027 and completion Aug 2030 → May 2030.
Earlier changes are on the record history on ClinicalTrials.gov ↗
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drugs tested here: Zanidatamab · Paclitaxel · Docetaxel · Carboplatin