NCT05256225 · National Cancer Institute (NCI)
Testing the Addition of Herceptin Hylecta or Phesgo to the Usual Chemotherapy for HER2 Positive Endometrial Serous Carcinoma or Carcinosarcoma
What this study is about
This phase III trial tests whether adding trastuzumab and hyaluronidase-oysk (Herceptin Hylecta \[TM\]) or pertuzumab, trastuzumab and hyaluronidase-zzxf (Phesgo \[TM\]) to the usual chemotherapy (paclitaxel and carboplatin) works to shrink tumors in patients with HER2 positive endometrial cancer.
View original scientific description
This phase III trial tests whether adding trastuzumab and hyaluronidase-oysk (Herceptin Hylecta \[TM\]) or pertuzumab, trastuzumab and hyaluronidase-zzxf (Phesgo \[TM\]) to the usual chemotherapy (paclitaxel and carboplatin) works to shrink tumors in patients with HER2 positive endometrial cancer. Trastuzumab and pertuzumab are monoclonal antibodies and forms of targeted therapy that attach to specific molecules (receptors) on the surface of tumor cells, known as HER2 receptors.
Interventions
PROCEDURE
Biospecimen Collection
Undergo blood and urine sample collection
DRUG
Carboplatin
Given IV
PROCEDURE
Computed Tomography
Undergo CT
PROCEDURE
Echocardiography Test
Undergo ECHO
RADIATION
High-Dose-Rate Vaginal Cuff Brachytherapy
Undergo vaginal brachytherapy
DRUG
Hyaluronidase-zzxf/Pertuzumab/Trastuzumab
Given SC
PROCEDURE
Multigated Acquisition Scan
Undergo MUGA
DRUG
Paclitaxel
Given IV
OTHER
Survey Administration
Ancillary studies
DRUG
Trastuzumab/Hyaluronidase-oysk
Given SC
Primary outcome measures
Progression free survival
Time frame: From study entry to time of progression or death, whichever occurs first, or date of last contact if neither progression nor death has occurred, assessed up to 5 years from randomization
At the end of Phase 2 analysis, if both experimental arms demonstrate superiority to the reference, the experimental arms will be compared to each other.
Overall survival
Time frame: From study entry to time of death or the date of last contact, assessed up to 5 years from randomization
If both experimental arms demonstrate superiority to the reference arm, the experimental arms will be compared to each other.
Incidence of dose limiting toxicities
Time frame: Up to end of cycle 3 (week 12)
A dose limiting toxicity is any treatment-related adverse event requiring permanent discontinuation of the experimental therapy prior to the completion of treatment cycle 3.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Federation of Gynecology and Obstetrics (FIGO) 2009 stage IA-IVB, non-recurrent, chemotherapy (chemo)-naive, HER2-positive endometrial cancer. The following endometrial cancer types are eligible:
- Other endometrial cancers (including clear cell, endometrioid, mixed epithelial, dedifferentiated/undifferentiated)
- Carcinosarcoma
- NOTE: Endometrial cancers that are mismatch repair deficient (dMMR) by IHC are not eligible
- Histologic confirmation of the original primary tumor is required. Submission of surgical pathology report (or endometrial biopsy pathology report in patients who never undergo hysterectomy) is required
- Patients must be within 8 weeks of primary surgery (or endometrial biopsy in patients who never undergo hysterectomy) at the time of study registration
- Patients may have measurable disease, non-measurable disease, or no measurable disease. In patients with measurable disease, lesions will be defined and monitored by RECI
Where
- Birmingham, Alabama
- Anchorage, Alaska
- Tucson, Arizona
- Little Rock, Arkansas
- Auburn, California
- Berkeley, California
- Concord, California
- Duarte, California
- Huntington Beach, California
- Irvine, California
- Long Beach, California
- Los Angeles, California
And 295 more locations — see the full list below.
Collaborators
NRG Oncology
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 24, 2026 · Source of record for eligibility and locations