A Study of 9MW2821 Versus Chemotherapy in Participants With Previously Treated Locally Advanced or Metastatic Triple-Negative Breast Cancer

A Randomized, Open-label, Phase 3 Study to Evaluate 9MW2821 Versus Investigator's Choice of Chemotherapy in Participants With Locally Advanced or Metastatic Triple-Negative Breast Cancer Who Have Previously Received Taxane-based Chemotherapy With or Without Immunotherapy and an Antibody-drug Conjugate With a Topoisomerase Inhibitor Payload

The purpose of this study is to compare the efficacy and safety of 9MW2821 versus investigator's choice of chemotherapy in participants with locally advanced or metastatic triple-negative breast cancer who have previously received taxane-based chemotherapy with or without immunotherapy and an antibody-drug conjugate with a topoisomerase inhibitor payload

Study Overview

• Status: Not yet recruiting
• Conditions: Locally Advanced or Metastatic Triple-negative Breast Cancer
• Intervention / Treatment: Drug: 9MW2821; Drug: Chemotherapy

• Study Type: Interventional
• Enrollment (Estimated): 356
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: Jian Zhang; Phone Number: 021-64175590; Email: syner2000@163.com
• Study Contact Backup: Name: Jiong Wu; Phone Number: 021-64175590; Email: wujiong1122@vip.sina.com

Study Locations

• China
  • Shanghai Municipality
    • Shanghai, Shanghai Municipality, China, 200032
      • Fudan University Shanghai Cancer Center
      • Contact: Jian Zhang; Phone Number: 021-64175590; Email: syner2000@163.com
      • Contact: Jiong Wu; Phone Number: 021-64175590; Email: wujiong1122@vip.sina.com

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Competent to comprehend, sign, and date an independent ethics committee/institutional review board/research ethics board (IEC/IRB/REB) approved informed consent form.
• Male or female subjects aged 18 to 75 years (including 18 and 75 years).
• ECOG 0-1.
• Histopathological diagnosed triple-negative breast cancer.
• Patient has previously received taxane-based chemotherapy with or without immunotherapy and an antibody-drug conjugate with a topoisomerase inhibitor payload.
• Suitable for one of active comparator chemotherapy assessed by investigator.
• An archival tumor tissue sample or a fresh tissue sample should be provided.
• Life expectancy of ≥ 12 weeks.
• Subjects must have measurable disease according to RECIST (version 1.1).
• Adequate organ functions.
• Sexually active fertile participants, and their partners, must agree to use methods of contraception during the study and at least 6 months after termination of study therapy.

Exclusion Criteria:

• Preexisting treatment related toxicity Grade ≥ 2 and Grade ≥ 3 immune related adverse reactions.
• Preexisting peripheral neuropathy Grade ≥ 2.
• Hemoglobin A1C (HbA1c) ≥ 8%.
• Has ocular conditions or symptoms that may increase the risk of the study.
• History of ILD or pneumotitis, other severe or uncontrolled disease or central nervous system metastases and/or meningeal metastasis.
• Previous medication does not meet the requirements.
• Known sensitivity to any of the ingredients of the investigational product; History of drug abuse or mental illness.
• Documented history of pulmonary embolism or clinically significant cardiac or cerebrovascular diseases .
• Active autoimmune disease.
• History of another malignancy .
• Pleural, abdominal, or pericardial effusion with clinical symptoms or that require drainage treatment.
• Not suitable to receive study treatment for other conditions as per investigator.

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: Experimental: 9MW2821; Participants will receive intravenous (IV) infusion of 9MW2821 as per protocol	Drug: 9MW2821; Subjects will receive intravenous (IV) infusion of 9MW2821 as per protocol
Active Comparator: Active Comparator: Investigator's Choice of Chemotherapy; Participants will receive investigator's choice of chemotherapy determined prior to randomization from 1 of the 4 allowed regimens as per protocol: eribulin, or vinorelbine or capecitabine or gemcitabine.	Drug: Chemotherapy; Participants will receive investigator's choice of chemotherapy determined prior to randomization from 1 of the 4 allowed regimens as per protocol: eribulin, or vinorelbine or capecitabine or gemcitabine.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Overall Survival	Time from the date of randomization until the date of death from any cause	Up to approximately 2 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of adverse events		Up to approximately 2 years
Objective Response Rate per investigator	The percentage of subjects who experience a best response of either CR or PR.	Up to approximately 2 years
Duration of Response per investigator	Time from the date of the first complete response (CR) or partial response (PR) to the earliest date of disease progression or death from any cause.	Up to approximately 2 years
Time to response per investigator	Time from the date of randomization to the date of CR or PR.	Up to approximately 2 years
Disease Control Rate per investigator	The percentage of subjects who experience a best response of CR, PR or stable disease (SD).	Up to approximately 2 years
Progression Free Survival per investigator	Time from the date of first randomization to the earliest date of documented disease progression per radiological evidence or death from any cause.	Up to approximately 2 years
Incidence of Anti-Drug Antibody (ADA)		Up to approximately 2 years

Collaborators and Investigators

• Sponsor: Mabwell (Shanghai) Bioscience Co., Ltd.

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): September 1, 2028

Study Registration Dates

• First Submitted: April 22, 2026
• First Submitted That Met QC Criteria: April 22, 2026
• First Posted (Actual): April 29, 2026

Study Record Updates

• Last Update Posted (Actual): April 30, 2026
• Last Update Submitted That Met QC Criteria: April 28, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: triple-negative breast cancer
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Breast Neoplasms; Skin and Connective Tissue Diseases; Triple Negative Breast Neoplasms; Therapeutics; Drug Therapy
• Other Study ID Numbers: 9MW2821-CP305

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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