Primary Prevention of Thrombocytopenia Associated With T-DM1 Therapy in HER2 Positive Breast Cancer With Herombopag

Ado-trastuzumab emtansine (T-DM1) demonstrates favorable efficacy in breast cancer treatment but is frequently associated with thrombocytopenia. Multiple studies indicate that Asian populations face a higher risk of developing thrombocytopenia during T-DM1 therapy, with incidence rates ranging from 52.5% to 69.8% and ≥Grade 3 rates between 29.8% and 45.0%. Severe thrombocytopenia not only increases bleeding risks but may also necessitate T-DM1 dose delays or reductions, thereby compromising treatment efficacy and diminishing patient survival and quality of life. Herombopag selectively binds to the transmembrane region of TPO-R, activating TPO-R-dependent STAT and MAPK signaling pathways. This effectively stimulates megakaryocyte proliferation and differentiation, promoting thrombopoiesis. However, high-level evidence supporting the use of Herombopag for primary prevention of T-DM1-induced thrombocytopenia in breast cancer remains lacking.

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Key information

Conditions

HER2-positive Breast Cancer

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Female, age ≥18 years;
Histopathologically or cytologically confirmed diagnosis of breast cancer;
Tumor tissue confirmed as HER2-positive, defined as immunohistochemistry (IHC) showing +++, or IHC++ with fluorescence in situ hybridization (FISH) demonstrating HER2-positive status;
Planned to receive T-DM1 regimen based on clinical judgment;
ECOG PS score: 0-2;
Expected survival greater than 12 weeks;
Adequate organ and bone marrow function.

Exclusion criteria

A confirmed history of severe allergic reactions to the active ingredients or excipients of the therapeutic drug;
Presence of other underlying diseases or comorbidities causing thrombocytopenia, such as aplastic anemia, immune thrombocytopenia, myelodysplastic syndrome, etc.;
Individuals with hereditary bleeding disorders, coagulation dysfunction, high bleeding risk, or a history of thrombotic events (e.g., transient ischemic attack, cerebral hemorrhage, cerebral infarction, pulmonary embolism) within 6 months prior to initial medication use;
Individuals with uncontrolled hypertension and a history of hypertensive crisis or hypertensive encephalopathy;
Pregnant or lactating women;
Presence of multiple factors affecting oral drug absorption, such as dysphagia, nausea/vomiting, chronic diarrhea, or intestinal obstruction;
History of severe psychiatric disorders, substance abuse, alcoholism, or drug addiction;
Currently participating in interventional clinical research treatment, or having received other investigational drugs or devices within 4 weeks prior to first dosing (individuals who failed screening for other clinical trials may be included in this study);
Any other factors deemed by the investigator to increase study risk, affect patient compliance with the protocol, or impact the patient's ability to complete the trial, such as physiological or psychological conditions that make participation in this study inappropriate;

Treatment and study plan

Herombopag

Drug

Each T-DM1 treatment cycle typically lasts 3 weeks, with prophylactic administration of eltrombopag continuing until 21 days after the end of that T-DM1 treatment cycle. Oral administration of eltrombopag ethanolamine tablets begins on the evening of the first day of each T-DM1 treatment cycle, starting at a dose of 7.5 mg once daily.

Primary outcomes

Incidence of thrombocytopenia (<100 × 10⁹/L)

Time frame: up to 6 cycles (each cycle is 21 days)

PLT <100 × 10⁹/L

Secondary outcomes

The time of the first occurrence of thrombocytopenia (<100 × 10⁹/L);

Time frame: up to 6 cycles (each cycle is 21 days)

Time at which PLT < 100 × 10⁹/L occurs
Incidence of AEs

Time frame: up to 6 cycles (each cycle is 21 days)

Record the occurrence of adverse events during the study period

Study contacts

Contact information is provided by the study sponsor or research team.

zhenzhen Liu, M.D.

CONTACT

[email protected]

13603862755

Sponsors and collaborators

Lead sponsor

Zhenzhen Liu

Other Gov

Registry information

Official study title

A Multicenter, Single-arm, Exploratory Clinical Study of Herombopag Olamine Tablets for the Primary Prevention of Treatment-related Thrombocytopenia in HER2-positive Breast Cancer Patients Receiving T-DM1 Therapy

Important dates

Study start: 2025
Primary completion: 2027
Study completion: 2028
First posted: Sep 30, 2025
Registry last updated: Sep 30, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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