Phase II Study of HLX43 Monotherapy or Combined With Immune Checkpoint Inhibitors in Patients With Locally Advanced, Recurrent, or Metastatic Triple-negative Breast Cancer.

March 17, 2026 updated by: Shanghai Henlius Biotech

A Phase II Study to Evaluate the Efficacy and Safety of HLX43 (an Anti-PD-L1 ADC) as a Monotherapy or in Combination With Immune Checkpoint Inhibitors in Subjects With Locally Advanced, Recurrent or Metastatic Triple-negative Breast Cancer (TNBC).

The study is being conducted to explore the reasonable dosage and evaluate the efficacy, safety and tolerability of HLX43 (Anti-PD-L1 ADC) as a monotherapy or in combination with immune checkpoint inhibitors in Subjects with locally advanced, recurrent or metastatic triple-negative breast cancer (TNBC).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
180

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • China
    • Heilongjiang
      • Harbin, Heilongjiang, China, 150081
        • Harbin Medical University Affiliated Cancer Hospital
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Voluntary written informed consent obtained before any study procedures.
  2. Age ≥ 18 years at consent; no gender restriction.

  3. Histopathologically confirmed TNBC: ER < 1%, PR < 1%, HER2 IHC 0/1+/2+ with no FISH amplification.

    • Phase I: Recurrent or metastatic TNBC after ≥1 prior line of standard systemic therapy.
    • Phase II: Unresectable locally advanced, recurrent, or metastatic TNBC with no prior systemic anti-cancer therapy for this stage (palliative radiotherapy to metastases allowed; neoadjuvant/adjuvant therapy permitted if completed ≥6 months before recurrence/metastasis).

  4. At least one RECIST v1.1-measurable lesion documented within 4 weeks before randomization.

    Note: Target lesions must not be in irradiated fields or the CNS. If only measurable lesion is irradiated, imaging must confirm progression post-radiotherapy.

  5. Archival FFPE tumor tissue (≤6 months old, ≤2 years max) for PD-L1 testing; fresh biopsy acceptable if archival tissue is unavailable or inadequate.

    Note: Specimens must be non-irradiated FFPE blocks/slides with pathology report confirming malignancy and adequacy.

  6. Washout: ≥3 weeks (or 5 half-lives, whichever is shorter) after major surgery, radiotherapy (except palliative bone RT), chemotherapy, targeted therapy, or immunotherapy; ≥1 week after minor surgery or anti-tumor TCM. All treatment-related AEs resolved to CTCAE v6.0 Grade ≤1 (stable Grade 2 peripheral neuropathy and alopecia exempted).
  7. ECOG PS 0-1, assessed ≤7 days before randomization.
  8. Life expectancy >3 months.
  9. Adequate hematologic, hepatic, and renal function per labs ≤7 days before randomization.

Exclusion Criteria:

  1. Prior topoisomerase I-targeting therapy (e.g., irinotecan, topotecan, or ADCs).
  2. Second primary malignancy within 2 years before randomization (except cured carcinoma in situ or stage I tumors).
  3. Prior grade ≥3 immune-related adverse event during immunotherapy.
  4. Uncontrolled, recurrent malignant pleural, pericardial, or ascitic effusions requiring repeated drainage.
  5. Active CNS metastases, spinal cord compression, or carcinomatous meningitis.
  6. Clinically significant pulmonary impairment.
  7. Uncontrolled cardiovascular or cerebrovascular disease .
  8. Active systemic infection requiring IV antibiotics within 2 weeks before randomization.
  9. Moderate or strong CYP2D6/CYP3A inhibitor or inducer use within 2 weeks before randomization.
  10. Systemic corticosteroids (>10 mg/day prednisone equivalent) or other immunosuppressants within 2 weeks before randomization .
  11. Active or suspected autoimmune disease .
  12. Live or attenuated live vaccine within 4 weeks before randomization.
  13. Hypersensitivity to mAbs, large-molecule biologics, or drug formulation excipients.
  14. Active pulmonary tuberculosis.
  15. Known immunodeficiency.
  16. Active HBV , HCV , or HBV/HCV co-infection.
  17. Pregnancy or lactation.
  18. Participation in another interventional trial within 30 days before consent .
  19. Any condition posing unacceptable safety risk or interfering with study conduct per investigator judgment.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: armA: HLX43 DOSE 1 in ≥2L TNBC
Patients with good tolerability and well controlled disease will receive the treatment once every 3 weeks (Q3W), Until disease progression, initiation of a new anti-tumor therapy, death, emergence of intolerable toxicity, or withdrawal of informed consent (whichever occurs first)
Drug: HLX43 DOSE 1 IN ≥2L TNBC
Dose 1; HLX43 is an anti-PD-L1 monoclonal antibody conjugated with a novel high potency DNA topoisomerase I (topo I) inhibitor, with a drug-antibody-ratio (DAR) of 8.
Experimental: armB: HLX43 DOSE 2 in ≥2L TNBC
Patients with good tolerability and well controlled disease will receive the treatment once every 3 weeks (Q3W), Until disease progression, initiation of a new anti-tumor therapy, death, emergence of intolerable toxicity, or withdrawal of informed consent (whichever occurs first)
Drug: HLX43 DOSE 2 IN ≥2L TNBC
Dose 2; HLX43 is an anti-PD-L1 monoclonal antibody conjugated with a novel high potency DNA topoisomerase I (topo I) inhibitor, with a drug-antibody-ratio (DAR) of 8.
Experimental: armC: HLX43 DOSE 1 in 1L TNBC
Patients with good tolerability and well controlled disease will receive the treatment once every 3 weeks (Q3W), Until disease progression, initiation of a new anti-tumor therapy, death, emergence of intolerable toxicity, or withdrawal of informed consent (whichever occurs first)
Drug: HLX43 DOSE1 IN 1L TNBC
HLX43 is an anti-PD-L1 monoclonal antibody conjugated with a novel high potency DNA topoisomerase I (topo I) inhibitor, with a drug-antibody-ratio (DAR) of 8.
Experimental: armD: HLX43 DOSE 2 in 1L TNBC
Patients with good tolerability and well controlled disease will receive the treatment once every 3 weeks (Q3W), Until disease progression, initiation of a new anti-tumor therapy, death, emergence of intolerable toxicity, or withdrawal of informed consent (whichever occurs first)
Drug: HLX43 DOSE 2 IN 1L TNBC
HLX43 is an anti-PD-L1 monoclonal antibody conjugated with a novel high potency DNA topoisomerase I (topo I) inhibitor, with a drug-antibody-ratio (DAR) of 8.
Experimental: armE: HLX43 DOSE 1+ HLX10 in 1L TNBC
Patients with good tolerability and well controlled disease will receive the treatment once every 3 weeks (Q3W), Until disease progression, initiation of a new anti-tumor therapy, death, emergence of intolerable toxicity, or withdrawal of informed consent (whichever occurs first)
Drug: HLX43 DOSE 1 + HLX10
HLX43 is an anti-PD-L1 monoclonal antibody conjugated with a novel high potency DNA topoisomerase I (topo I) inhibitor, with a drug-antibody-ratio (DAR) of 8. HLX10 is a humanized anti-PD-1 monoclonal antibody that functions as an immune checkpoint inhibitor.
Experimental: armF: HLX43 DOSE 2+ HLX10 in 1L TNBC
Patients with good tolerability and well controlled disease will receive the treatment once every 3 weeks (Q3W), Until disease progression, initiation of a new anti-tumor therapy, death, emergence of intolerable toxicity, or withdrawal of informed consent (whichever occurs first)
Drug: HLX43 DOSE2 + HLX10
HLX43 is an anti-PD-L1 monoclonal antibody conjugated with a novel high potency DNA topoisomerase I (topo I) inhibitor, with a drug-antibody-ratio (DAR) of 8. HLX10 is a humanized anti-PD-1 monoclonal antibody that functions as an immune checkpoint inhibitor.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
ORR
Time Frame: up to 24 weeks
Objective response rate (ORR) (assessed by BICR according to the RECIST v1.1 criteria)
up to 24 weeks
PFS
Time Frame: From date of randomization until the date of first documented progression or date of death from any cause, whichever came first, assessed up to 10 months
Defined as the time (in months) from randomization to the first confirmed and documented progressive disease or death (whichever occurs first) as assessed by BICR according to the RECIST v1.1 criteria.
From date of randomization until the date of first documented progression or date of death from any cause, whichever came first, assessed up to 10 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Shanghai Henlius Biotech

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 25, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 15, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 22, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 17, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 17, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 23, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 23, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 17, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • HLX43-BC202

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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Sponsors and Collaborators

Medical Conditions

Drug Interventions

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

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