A Study Comparing BL-B01D1 With Chemotherapy of Physician's Choice in Patients With Unresectable Locally Advanced, Recurrent, or Metastatic HR+/HER2- Breast Cancer After Failure of Prior Endocrine Therapy(PANKU-Breast03)

A Phase III Randomized Controlled Clinical Study Comparing BL-B01D1 With Chemotherapy of Physician's Choice in Patients With Unresectable Locally Advanced, Recurrent, or Metastatic HR+/HER2- Breast Cancer After Failure of Prior Endocrine Therapy(PANKU-Breast03)

This trial is a registrational Phase III, randomized, open-label, multicenter study to evaluate the efficacy and safety of BL-B01D1 in patients with unresectable locally advanced, recurrent, or metastatic HR+/HER2- breast cancer after failure of prior endocrine therapy.

Study Overview

• Status: Recruiting
• Conditions: Breast Cancer
• Intervention / Treatment: Drug: BL-B01D1; Drug: Capecitabine; Drug: Paclitaxel; Drug: Albumin-Bound Paclitaxel

Detailed Description

In this trial, the experimental group receives BL-B01D1, and the control group receives chemotherapy of physician's choice.

• Study Type: Interventional
• Enrollment (Estimated): 446
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: Sa Xiao, PHD; Phone Number: 15013238943; Email: xiaosa@baili-pharm.com

Study Locations

• China
  • Beijing Municipality
    • Beijing, Beijing Municipality, China
      • Recruiting
      • Cancer Hospital Chinese Academy of Medical Sciences
      • Contact: Binghei Xu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Voluntarily sign the informed consent form and comply with the protocol requirements;
2. No gender restrictions;
3. Age ≥ 18 years;
4. Expected survival time ≥ 3 months;
5. Patients with unresectable locally advanced, recurrent, or metastatic HR+ HER2- breast cancer;
6. Trial participants have not received systemic chemotherapy;
7. Trial participants have progressed after at least one line of endocrine therapy, etc.;
8. Documented radiographic disease progression prior to enrollment;
9. Agree to provide archived tumor tissue specimens or fresh tissue samples from the primary or metastatic lesion within 3 years;
10. Must have at least one measurable lesion as defined by RECIST v1.1;
11. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1;
12. Toxicity from prior anti-tumor therapy must have recovered to ≤ Grade 1 as defined by NCI-CTCAE v6.0;
13. No severe cardiac dysfunction, with left ventricular ejection fraction (LVEF) ≥ 50%;
14. Must meet required organ function levels;
15. Urinary protein ≤ 2+ or < 1000 mg/24h;
16. For premenopausal women of childbearing potential, a pregnancy test must be performed within 7 days before starting treatment, with a negative serum pregnancy result, and they must not be breastfeeding; all enrolled patients (regardless of gender) must use adequate barrier contraception throughout the treatment period and for 6 months after treatment ends.

Exclusion Criteria:

1. Previously treated with ADC drugs that use topoisomerase I inhibitors as the toxin or target EGFR and/or HER3;
2. Use of chemotherapy, biotherapy, immunotherapy, etc., within 4 weeks or 5 half-lives before the first dose;
3. Previous treatment with anthracycline drugs where the equivalent cumulative dose of doxorubicin exceeds 360 mg/m²;
4. History of severe cardiovascular or cerebrovascular diseases;
5. Unstable thrombotic events requiring therapeutic intervention within 6 months before screening;
6. Prolonged QT interval, complete left bundle branch block, etc.;
7. Diagnosis of another malignancy within 3 years before the first dose;
8. Hypertension poorly controlled by two antihypertensive medications;
9. Poorly controlled blood glucose levels;
10. History of ILD requiring steroid therapy, current ILD, or grade ≥2 radiation pneumonitis, etc.;
11. Concurrent pulmonary diseases causing clinically severe respiratory function impairment;
12. Patients with active central nervous system metastases;
13. Presence of large serous cavity effusions or symptomatic serous cavity effusions, etc.;
14. Imaging findings indicating tumor invasion or encasement of the abdomen, chest, etc.;
15. Severe infection within 4 weeks before study randomization;
16. Severe, unhealed wounds, ulcers, or fractures within 4 weeks before signing the informed consent form;
17. Trial participants with clinically significant bleeding or a significant bleeding tendency within 4 weeks prior to signing the informed consent form;
18. History of inflammatory bowel disease, extensive bowel resection, etc.;
19. Patients with a history of allergy to recombinant humanized antibodies or allergy to BL-B01D1 or any of its excipients;
20. History of autologous or allogeneic stem cell transplantation;
21. Positive for human immunodeficiency virus antibodies, active hepatitis B virus infection, or hepatitis C virus infection;
22. Receipt of other unapproved clinical study drugs or treatments within 4 weeks before the first dose;
23. Trial participants planning to receive or having received live vaccines within 28 days before the first dose;
24. Other conditions deemed by the investigator to be unsuitable for participation in this clinical trial due to complications or other reasons.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: BL-B01D1; Participants receive BL-B01D1 in the first cycle (3 weeks). Participants with clinical benefit could receive additional treatment for more cycles. The administration will be terminated because of disease progression or intolerable toxicity occurring or other reasons.	Drug: BL-B01D1; Administration by intravenous infusion for a cycle of 3 weeks.; Other Names: BMS-986507; iza-bren; izalontamab brengitecan
Active Comparator: Albumin-bound paclitaxel, paclitaxel, or capecitabine; Participants receive Albumin-bound paclitaxel, paclitaxel, or capecitabine in the first cycle. Participants with clinical benefit could receive additional treatment for more cycles. The administration will be terminated because of disease progression or intolerable toxicity occurring or other reasons.	Drug: Capecitabine; Oral administration for a cycle of 3 weeks.; Drug: Paclitaxel; Administration by intravenous infusion for a cycle of 3 weeks.; Drug: Albumin-Bound Paclitaxel; Administration by intravenous infusion for a cycle of 4 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Progression-free survival (PFS)	Progression-free survival (PFS) as assessed by BICR is defined as the time between the date subjects were randomized and the first observation of disease progression (based on BICR's image-based assessment) or death.	Up to approximately 24 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Objective Response Rate (ORR)	Objective response rate (ORR) is defined as the number of CR and PR in the treatment and control groups divided by the number of that group in the full analysis set (FAS).	Up to approximately 24 months
Disease Control Rate (DCR)	Disease Control Rate (DCR) : Percentage of all randomized subjects who rated the best overall response (BOR) as complete response (CR), partial response (PR), and disease stabilization (SD) according to RECIST 1.1 criteria.	Up to approximately 24 months
Duration of Response (DOR)	Duration of Response (DOR) : defined as the period from the date when tumor response is first recorded to the date when objective tumor progression is first recorded or the date of death.	Up to approximately 24 months
Treatment Emergent Adverse Event (TEAE)	TEAE is defined as any unfavorable and unintended change in the structure, function, or chemistry of the body temporally emerging, or any worsening (i.e., any clinically significant adverse change in frequency and/or intensity) of a pre-existing condition during the treatment of BL-B01D1. The type, frequency and severity of TEAE will be evaluated during the treatment of BL-B01D1.	Up to approximately 24 months
Anti-drug antibody (ADA)	Frequency of anti-BL-B01D1 antibody (ADA) will be investigated.	Up to approximately 24 months
Overall Survival (OS)	Overall survival (OS) is defined as the time between the day the subject is randomized and the subject's death.	Up to approximately 24 months

Collaborators and Investigators

• Sponsor: Sichuan Baili Pharmaceutical Co., Ltd.
• Collaborators: Baili-Bio (Chengdu) Pharmaceutical Co., Ltd.

Study record dates

Study Major Dates

• Study Start (Actual): July 6, 2026
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): December 1, 2028

Study Registration Dates

• First Submitted: June 8, 2026
• First Submitted That Met QC Criteria: June 10, 2026
• First Posted (Actual): June 15, 2026

Study Record Updates

• Last Update Posted (Actual): July 23, 2026
• Last Update Submitted That Met QC Criteria: July 21, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms; Amino Acids, Peptides, and Proteins; Proteins; Organic Chemicals; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Nucleic Acids, Nucleotides, and Nucleosides; Hydrocarbons; Cycloparaffins; Hydrocarbons, Alicyclic; Hydrocarbons, Cyclic; Terpenes; Taxoids; Cyclodecanes; Diterpenes; Deoxycytidine; Cytidine; Pyrimidine Nucleosides; Pyrimidines; Nucleosides; Uracil; Pyrimidinones; Deoxyribonucleosides; Fluorouracil; Albumins; Capecitabine; Albumin-Bound Paclitaxel; Paclitaxel
• Other Study ID Numbers: BL-B01D1-321

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No