A Phase II Study to Evaluate the Efficacy and Safety of HLX43 in Patients With Hormone Receptor Positive, HER2 Negative Locally Advanced or Metastatic Breast Cancer

A Phase II Study to Evaluate the Efficacy and Safety of HLX43 (Anti-PD-L1 ADC) in Patients With Hormone Receptor Positive, HER2 Negative Locally Advanced or Metastatic Breast Cancer

Status

Not yet recruiting

Phases

Phase 2

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT07459738

Enrollment

Registered

2026-03-10

Start date

2026-04-01

Completion date

2027-12-30

Last updated

2026-03-10

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Hormone Receptor Positive HER-2 Negative Breast Cancer

Keywords

HLX43, anti-PD-L1 ADC, Breast Cancer

Brief summary

This is a Phase II Study of HLX43 in Hormone Receptor Positive，HER-2 negative Locally Advanced or Metastatic Breast Cancer Patients with Disease Progression on Standard of Care. Eligible subjects will be treated with the study drug until the loss of clinical benefit, death, intolerable toxicity, withdrawal of informed consent, or other reasons specified by the protocol (whichever occurs first)

Interventions

DRUGHLX43

HLX43 is an anti-PD-L1 monoclonal antibody conjugated with a novel high potency DNA topoisomerase I (topo I) inhibitor, with a drug-antibodyratio (DAR) of 8.

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

18 Years to 75 Years

Healthy volunteers

Inclusion criteria

1. Male/female who are at least 18 years of age and and no more than 75 years old on the day of signing the informed consent. 2. With histologically confirmed diagnosis of HER2-negative, Hormone Receptor Positive Locally Advanced or Metastatic Breast Cancer. 3. Must have experienced disease progression after receiving at least one line of endocrine therapy for advanced or metastatic disease. 4. Had measurable disease according to the RECIST v1.1, the target lesion must not be a bone metastatic lesion only. 5. ECOG PS: 0-1. 6. Expected survival ≥ 6 months. 7. Had adequate organ function

Exclusion criteria

1. Patients with other malignant tumors within 3 years before the randomization 2. Prior documented interstitial lung disease (ILD)/ pneumonitis that required steroids, current ILD/ pneumonitis, or suspected ILD/pneumonitis 3. Lung-specific intercurrent clinically significant illnesses 4. Uncontrolled or significant cardiovascular disease or infection 5. Prior adverse events leading to permanent discontinuation of immunotherapy; or prior immune-related pneumonia or immune-related myocarditis of grade ≥2.

Design outcomes

Primary

Measure	Time frame	Description
ORR	Up to 24WEEK	Objective response rate (ORR) assessed by IRRC (Independent Radiology Review Committee) per RECIST 1.1
PFS	Up to 5 years	Progression-Free Survival (PFS) assessed by IRRC (Independent Radiology Review Committee) per RECIST 1.1

Contacts

CONTACTLiman Zhang

liman_zhang@henlius.com18501255848

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Mar 11, 2026