A Study of SKB264 Versus Investigator's Choice of Chemotherapy in Subjects With Unresectable Locally Advanced, Relapsed, or Metastatic HR+/HER2- Breast Cancer Who Have Previously Failed Endocrine Therapy

NCT07071337 | Recruiting Phase 3 DMC

• 1 other identifier: SKB264-Ⅲ-13
• Study Type: interventional
• Target: 430
• Locations: 1 country
• Sites: 2

Brief Summary

The purpose of this study is to evaluate the efficacy and safety of SKB264 in patients with unresectable locally advanced, recurrent, or metastatic HR+/HER2- breast cancer who have previously failed endocrine therapy.

Conditions

Metastatic Breast Cancer

Keywords

SKB264; HR+/HER2- breast cancer

Outcome Measures

Primary Outcomes (1)

• Progression Free Survival (PFS) assessed by Blinded Independent Central Review (BICR)

  PFS is defined as the time from randomization to the first documented disease progression per RECIST 1.1 based on BICR or death due to any cause, whichever occurs first

  Randomization up to approximately 24 months

Secondary Outcomes (12)

• Overall Survival (OS)

  Randomization up to approximately 67 months

• Progression-Free Survival (PFS) assessed by Investigator

  Randomization up to approximately 24 months

• Objective Response Rate (ORR)

  Randomization up to approximately 24 months

• Disease control rate (DCR)

  Randomization up to approximately 24 months

• Duration of Response (DoR)

  Randomization up to approximately 24 months

Study Arms (2)

SKB264

EXPERIMENTAL

Drug: SKB264

Investigator's Choice of Chemotherapy

ACTIVE COMPARATOR

Nab-paclitaxel, paclitaxel or capecitabine will be administered and managed according to the investigator's clinical judgment, guided by clinical practice.

Drug: Nab-paclitaxel; Drug: Paclitaxel; Drug: Capecitabine

Interventions

SKB264 DRUG

5mg/kg, IV on Day 1 and Day 15 of each 28 day cycle

SKB264

Nab-paclitaxel DRUG

100 mg/m\^2, IV, on Days 1, 8, and 15 every 4 weeks

Investigator's Choice of Chemotherapy

Paclitaxel DRUG

90 mg/m\^2, IV, on Days 1, 8, and 15 every 4 weeks; or 80 mg/m\^2, IV, weekly, every 3 weeks

Investigator's Choice of Chemotherapy

Capecitabine DRUG

1000-1250 mg/m\^2, orally, Days 1-14, twice daily, every 3 weeks

Investigator's Choice of Chemotherapy

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Aged ≥ 18 and ≤ 75 years at the time of signing the ICF, male or female;
• Histologically and/or cytologically confirmed HR+/HER2- BC based on pathological reports from the most recent biopsy or other pathological specimens;
• Subjects must have radiologically documented disease progression during or after the most recent treatment prior to enrollment;
• The investigator assessed that the patient could not continue to benefit from endocrine therapy and was suitable for receiving first-line chemotherapy;
• Able to provide recently newly obtained or archival tumor tissue sections at or after diagnosis of relapsed or metastatic tumor within the recent prior to randomization;
• At least one measurable lesion per RECIST v1.1；
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1 with no worsening within 2 weeks prior to randomization;
• Life expectancy of ≥ 12 weeks;
• Suitable to receive one of the chemotherapy regimens listed in the investigator's choice of chemotherapy (paclitaxel, nab-paclitaxel, capecitabine) as assessed by the investigator;
• Adequate organ and bone marrow function;
• Having recovered from all toxicities due to prior treatment;
• Use of effective medical contraception during study treatment and for 6 months after the end of dosing for female subjects of childbearing potential and male subjects with partners of childbearing potential;
• Willingness to participate in the study, sign the ICF, and comply with the protocol-specified visits and relevant procedures.

You may not qualify if:

• Subjects with locally advanced breast cancer suitable for curative therapy at study enrollment;
• Other malignancies (except those tumors cured by local treatment, such as basal cell carcinoma of skin, squamous cell carcinoma of skin, carcinoma in situ of the cervix) within 3 years prior to randomization;
• Subiects with known meningeal metastases, brainstem metastases, spinal cord metastases and/or compression or active centralnervous system (CNS) metastases.
• Presence of any serious cardiovascular and cerebrovascular diseases or cardiovascular and cerebrovascular risk factors;
• History of (noninfectious) interstitial lung disease (ILD)/noninfectious pneumonitis requiring steroid therapy and current ILD/noninfectious pneumonitis, or suspected ILD/noninfectious pneumonitis at screening that cannot be excluded by imaging;
• Clinically serious lung injuries caused by lung diseases;
• Serious infection within 4 weeks prior to randomization, including but not limited to complications requiring hospitalization, sepsis, or severe pneumonia; active infection requiring systemic anti-infective therapy within 2 weeks prior to randomization;
• Documented severe dry eye syndrome, severe meibomian gland dysfunction and/or blepharitis, or history of severe corneal disorders that prevent/delay corneal healing;
• History of esophagogastric varices, severe ulcers, gastric perforation, gastrointestinal obstruction, intra-abdominal abscess, or acute gastrointestinal bleeding within 6 months prior to randomization;
• Active hepatitis B (hepatitis B surface antigen positive and HBV-DNA ≥ 500 IU/mL or above the ULN, whichever is higher) or hepatitis C (hepatitis C antibody positive and HCV-RNA above the ULN);
• Positive result of human immunodeficiency virus (HIV) test or history of acquired immunodeficiency syndrome (AIDS); known active syphilis infection;
• Known hypersensitivity to SKB264 or investigator's choice chemotherapy or any of its excipients, including but not limited to polysorbate-20, or history of severe hypersensitivity reaction to other monoclonal antibodies;
• Known history of allogeneic organ transplantation and allogeneic hematopoietic stem cell transplantation.
• Pregnant or lactating women;
• Prior TROP2-targeted therapy or any treatment containing chemotherapeutic agents targeting topoisomerase I (including antibody-drug conjugates \[ADCs\]);

Sponsors & Collaborators

• Sichuan Kelun-Biotech Biopharmaceutical Co., Ltd.: lead

Study Sites (2)

The Fifth Medical Center of the Chinese PLA General Hospital

Beijing, Beijing Municipality, 100039, China

RECRUITING

Sun Yat-sen University Cancer Center

Guangzhou, Guangdong, 510060, China

RECRUITING

MeSH Terms

Conditions

Breast Neoplasms

Interventions

130-nm albumin-bound paclitaxel; Paclitaxel; Capecitabine

Condition Hierarchy (Ancestors)

Neoplasms by Site; Neoplasms; Breast Diseases; Skin Diseases; Skin and Connective Tissue Diseases

Intervention Hierarchy (Ancestors)

Taxoids; Cyclodecanes; Cycloparaffins; Hydrocarbons, Alicyclic; Hydrocarbons, Cyclic; Hydrocarbons; Organic Chemicals; Diterpenes; Terpenes; Deoxycytidine; Cytidine; Pyrimidine Nucleosides; Pyrimidines; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Fluorouracil; Uracil; Pyrimidinones; Deoxyribonucleosides; Nucleosides; Nucleic Acids, Nucleotides, and Nucleosides

Central Study Contacts

Yina Diao

CONTACT

86-028-67252634; diaoyina@kelun.com

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: Participants will be randomised in a 1:1 ratio to one of two intervention groups

Study Record Dates

• First Submitted: June 19, 2025
• First Posted: July 17, 2025
• Study Start: July 18, 2025
• Primary Completion (Estimated): July 1, 2027
• Study Completion (Estimated): February 1, 2031
• Last Updated: December 11, 2025

Record last verified: 2025-12

Locations

CN (2)