Efficacy and Safety of Trastuzumab Rezetecan or Trastuzumab Deruxtecan in Advanced Breast Cancer

A Comparison of the Efficacy and Safety of Trastuzumab Rezetecan(SHR-A1811) Versus Trastuzumab Deruxtecan(DS-8201) in Patients With HER2-Positive Metastatic Breast Cancer Previously Treated With Trastuzumab

This study is a prospective, open-label, multicenter, randomized, parallel Phase II clinical trial. This study aims to investigate the efficacy and safety of trastuzumab rezetecan or trastuzumab deruxtecan in HER2 positive advanced/metastastic breast cancer

Study Overview

• Status: Not yet recruiting
• Conditions: Advanced Breast Cancer
• Intervention / Treatment: Drug: Trastuzumab Rezetecan for Injection (SHR-A1811); Drug: Trastuzumab Deruxtecan for Injection (T-DXd)

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Erwei Song, PhD, MD; Phone Number: +86-13926477694; Email: songew@mail.sysu.edu.cn
• Study Contact Backup: Name: herui Yao, PhD, MD; Phone Number: +86 13500018020; Email: yaoherui@163.com

Study Locations

• China
  • Guangdong
    • Guangzhou, Guangdong, China
      • Sun Yat-Sen Memorial Hospital
      • Contact: Jianli Zhao, MD; Phone Number: +86 15920589334; Email: zhaojianli@163.com

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Female patients aged ≥18 and ≤75 years.
• Histologically or cytologically confirmed HER2-positive (IHC 3+ and/or ISH positive) unresectable or metastatic breast cancer.
• Prior treatment with trastuzumab and a taxane in the recurrent or metastatic setting. Or recurrence during or within 12 months (disease-free interval, DFI) after completing neoadjuvant/adjuvant chemotherapy and/or anti-HER2 targeted therapy.
• Documented radiological disease progression (during or after the most recent prior therapy).
• ECOG Performance Status of 0 or 1.
• At least one measurable lesion according to RECIST v1.1 criteria.
• Adequate organ function meeting the following criteria (without the use of any blood components, cytokines, or growth factors for correction within 14 days prior to the first dose):

Absolute neutrophil count (ANC) ≥1.5 × 10⁹/L; Platelet count (PLT) ≥100 × 10⁹/L; Hemoglobin (Hb) ≥90 g/L (9.0 g/dL); Albumin ≥3.0 g/dL;Total bilirubin ≤1.5 × ULN; Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤2.5 × ULN (≤5.0 × ULN for patients with liver metastases); Serum creatinine ≤1.5 × ULN OR creatinine clearance ≥60 mL/min (calculated using the Cockcroft-Gault formula); QTcF interval ≤470 ms; Left ventricular ejection fraction (LVEF) ≥50% as measured by echocardiography (ECHO) or multigated acquisition scan (MUGA)

• Female subjects of childbearing potential must have a negative pregnancy test at screening and must agree to use highly effective contraception methods from the signing of the informed consent form until 7 months after the last dose of the investigational product.
• Willing and able to provide written informed consent, with good compliance, and willing to cooperate with follow-up visits and study-related procedures.

Exclusion Criteria:

• Patients with known untreated spinal cord compression or active central nervous system (CNS) metastases, except for those who have been treated and have remained stable for at least 1 month and have discontinued corticosteroids for >2 weeks.
• History of other malignancies within the past 5 years, excluding cured basal cell carcinoma of the skin and carcinoma in situ of the cervix.
• Uncontrolled third-space fluid accumulation (e.g., massive ascites, pleural effusion, pericardial effusion) that cannot be managed by drainage or other methods.
• Having undergone major cancer-related surgery, radiotherapy, chemotherapy, immunotherapy, molecular targeted therapy, biotherapy, or other clinical investigational therapy within 4 weeks prior to the first dose.
• Prior treatment with an antibody-drug conjugate containing an exatecan derivative (a topoisomerase I inhibitor).
• Use of immunosuppressants or systemic corticosteroids for immunosuppressive purposes (at doses >10 mg/day prednisone or equivalent) within 2 weeks prior to the first dose, excluding topical, nasal spray, or inhaled corticosteroids.
• Presence of any active autoimmune disease or a history of autoimmune disease that may potentially recur.
• History of immunodeficiency, including a positive HIV test, other acquired or congenital immunodeficiency diseases, or a history of organ transplantation.
• Patients with known or suspected interstitial lung disease (ILD); or presence of other moderate-to-severe pulmonary diseases that may significantly impair respiratory function or interfere with the detection or management of drug-related pulmonary toxicity within 3 months prior to the first dose, including but not limited to idiopathic pulmonary fibrosis, organizing pneumonia/bronchiolitis obliterans, pulmonary embolism, severe asthma, severe chronic obstructive pulmonary disease (COPD), obstructive/restrictive lung disease, etc.; and any autoimmune, connective tissue, or inflammatory disorders involving the lungs, such as rheumatoid arthritis, Sjögren's syndrome, sarcoidosis, etc.; or history of pneumonectomy. Patients who experienced ≥Grade 3 ILD during prior treatment with immune checkpoint inhibitors are excluded.
• Presence of active hepatitis B (HBsAg positive and HBV DNA ≥500 IU/mL), hepatitis C (anti-HCV positive and HCV RNA above the upper limit of normal), or liver cirrhosis; or severe infections requiring systemic antibiotic, antiviral, or antifungal therapy.
• Toxicities from prior anti-tumor therapy that have not recovered to ≤ Grade 1 (according to NCI-CTCAE v6.0).
• Known hypersensitivity to any of the study drugs or their excipients.
• Any other severe physical or mental illness or abnormal laboratory finding that, in the investigator's judgment, may increase the risk associated with study participation, interfere with the study results, or make the patient unsuitable for participation in this study.

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: SHR-A1811	Drug: Trastuzumab Rezetecan for Injection (SHR-A1811); SHR-A1811 4.8mg/kg iv q3w; Other Names: SHR-A1811; T-DXh; Trastuzumab rezetecan
Active Comparator: T-DXd	Drug: Trastuzumab Deruxtecan for Injection (T-DXd); T-DXd 5.4mg/kg iv q3w; Other Names: T-DXd; DS-8201; Trastuzumab deruxtecan

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Progression Free Survival(PFS)	Time from the date of randomization until the date of first documented radiological disease progression (PD) or death from any cause, whichever occurs first. If a subject did not experience PD or death by the data cutoff date, or had received other anti-tumor therapy, censoring occurred at the date of the last efficacy assessment prior to the cutoff date or the start date of other anti-tumor therapy, whichever was earlier.	From the date of randomization to the earliest date of the first objective documentation of radiographic disease progression or death due to any cause, up to approximately 3 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Treatment-Emergent Adverse Events (TEAEs) and Treatment-Emergent Serious Adverse Events(TESAEs)		From first dose of study drug (Day 1) up to approximately 3 years
Objective response rate (ORR)	The percentage of subjects in the analysis set whose best overall response (BOR) was a complete response (CR) or partial response (PR) from the start of the study treatment until the subject discontinued the study due to disease progression. It is recommended to use the Response Evaluation Criteria in Solid Tumors (RECIST 1.1) to evaluate the objective tumor response. Subjects must have measurable tumor lesions at baseline, and the assessment of efficacy is recommended to be categorized according to RECIST 1.1 criteria into complete response (CR), partial response (PR), stable disease (SD), and progressive disease (PD).	From screening and every 6 weeks up to withdrawal of subject consent, progressive disease (PD), or unacceptable toxicity, up to approximately 3 years
Disease control rate(DCR)	The percentage of subjects in the analysis set whose best overall response (BOR) was complete response (CR), partial response (PR), or stable disease (SD) from the start of the study treatment regimen until the subject discontinued the study due to disease progression. It is recommended to use the Response Evaluation Criteria in Solid Tumors (RECIST 1.1) to assess the objective tumor response. Subjects must have measurable tumor lesions at baseline, and the efficacy assessment is recommended to be categorized according to RECIST 1.1 criteria as complete response (CR), partial response (PR), stable disease (SD), and progressive disease (PD).	From screening and every 6 weeks up to withdrawal of subject consent, progressive disease (PD), or unacceptable toxicity, up to approximately 3 years
Duration of Response(DOR)	defined as the time from the date of first documented response (complete response, CR, or partial response, PR, whichever occurs first) to the date of disease progression or death, whichever occurs earlier. Response is assessed using the Response Evaluation Criteria in Solid Tumors (RECIST 1.1).	From the date of the first documented objective response (CR or PR) to the first documented disease progression or death, whichever occurs first, up to approximately 3 years
Overall survival (OS)	Defined as the time from the date of enrollment to the date of death from any cause. For subjects who were alive at the last follow-up, their OS data are censored at the date of the last follow-up. For subjects who were lost to follow-up, their OS data are censored at the date of the last documented evidence of survival prior to being lost. Censored OS is defined as the time from enrollment to censoring.	From the date of randomization up to the date of death due to any cause, up to approximately 3 years

Collaborators and Investigators

• Sponsor: Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): June 1, 2031
• Study Completion (Estimated): December 1, 2031

Study Registration Dates

• First Submitted: June 1, 2026
• First Submitted That Met QC Criteria: June 1, 2026
• First Posted (Actual): June 5, 2026

Study Record Updates

• Last Update Posted (Actual): June 5, 2026
• Last Update Submitted That Met QC Criteria: June 1, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: advanced breast cancer; ADC; T-DXd; SHR-A1811
• Additional Relevant MeSH Terms: Therapeutics; Drug Administration Routes; Drug Therapy; Injections; trastuzumab deruxtecan
• Other Study ID Numbers: MA-BC-II-137

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

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