A Randomized, Open-Label, Multicenter Phase II Clinical Study of Different Doses of Trastuzumab Rezetecan for Injection or Trastuzumab Deruxtecan for Injection in the Treatment of Unresectable Locally Recurrent/Metastatic Breast Cancer With HR-Positive and HER2-Low Expression

Plain English Summary

A Trial of Trastuzumab Rezetecan in Unresectable Locally Recurrent/Metastatic Breast Cancer is a Phase 2 clinical trial sponsored by Jiangsu HengRui Medicine Co., Ltd. studying Unresectable Locally Recurrent Breast Cancer, Unresectable Locally Metastatic Breast Cancer. This trial tests two drugs, Trastuzumab Rezetecan and Trastuzumab Deruxtecan, at different doses. It is for women aged 18-75 with advanced breast cancer that has spread and is HR-positive and HER2-low. Participation involves receiving one of the study drugs and regular check-ups, scans, and blood tests. Alternative treatments may include endocrine therapy or other chemotherapy regimens. The trial aims to enroll 150 participants.

Official Summary

The study is designed to compare the efficacy and safety of different dose groups of Trastuzumab Rezetecan or Trastuzumab Deruxtecan in patients with HR-positive, HER2-low unresectable locally recurrent/metastatic breast cancer. It will also exploratively evaluate the pharmacokinetic profile and immunogenicity of Trastuzumab Rezetecan.

Who Can Participate

Here is what you need to know about eligibility for this trial. Women aged 18 to 75 with breast cancer that cannot be removed and has spread. Patients must have had prior endocrine therapy for their advanced cancer that is no longer working. Patients cannot have brain metastases or certain other serious health conditions. Good general health and organ function are required. This trial is studying Unresectable Locally Recurrent Breast Cancer, Unresectable Locally Metastatic Breast Cancer, so participants generally need a confirmed diagnosis.

What They're Measuring

Progression-free survival means how long patients live without their cancer getting worse, which is a key measure of how well the treatment is working. The specific primary outcome measures are: Progression-free survival (PFS). (Every 6 weeks after administration, approximately 14 months.). These endpoints are how researchers determine whether the treatment is effective and will form the basis of any future regulatory submissions.

About This Phase

This trial is in Phase 2, which tests whether the treatment actually works against the target condition. Phase 2 trials involve 100-300 patients and continue to monitor safety while evaluating effectiveness. This phase often tests different dosages to find the optimal amount. About 33% of Phase 2 drugs advance to Phase 3. If successful, the treatment will move to large-scale Phase 3 trials needed for FDA approval.

Why This Trial Matters

This trial addresses a need for more effective treatments for a specific subtype of advanced breast cancer (HR-positive, HER2-low) where current options may be limited. Phase 2 success would typically lead to larger Phase 3 trials needed for regulatory approval. This research targets Unresectable Locally Recurrent Breast Cancer, Unresectable Locally Metastatic Breast Cancer, where improved treatment options are needed.

Investor Insight

This trial is sponsored by a pharmaceutical company, indicating investment in developing new cancer therapies, with potential for future market entry if successful. Phase 2 trials have approximately a 15-20% chance of eventually gaining FDA approval.

Is This Trial Right for Me?

Ask your doctor about the specific drugs being tested and how they might affect you. Understand the schedule of visits, tests, and potential side effects involved in the trial. Discuss how this trial fits with other treatment options you may have. The trial is being conducted at 1 site. Always discuss clinical trial participation with your healthcare provider before making any decisions. This information is for educational purposes only and is not medical advice.

AI-generated analysis for educational purposes only. This is not medical advice. Discuss clinical trial participation with your doctor. Data sourced from ClinicalTrials.gov.

Study Design

• Study Type: INTERVENTIONAL
• Allocation: RANDOMIZED
• Model: PARALLEL
• Masking: NONE
• Enrollment: 150 participants

Interventions

• DRUG: Trastuzumab Rezetecan for Injection — Trastuzumab Rezetecan for injection.
• DRUG: Trastuzumab Deruxtecan for Injection — Trastuzumab Deruxtecan for injection.

Primary Outcomes

• Progression-free survival (PFS). (Every 6 weeks after administration, approximately 14 months.)

Secondary Outcomes

• Objective response rate (ORR). (Every 6 weeks after administration, approximately 14 months.)
• Duration of response (DoR). (Every 6 weeks after administration, approximately 14 months.)
• Clinical benefit rate (CBR). (Every 6 weeks after administration, approximately 14 months.)
• Adverse events (AEs). (From the first dose administration until 40 days after the last dose administration.)
• Laboratory test indicators, including complete blood count. (From the first dose administration until 40 days after the last dose administration.)

Full Eligibility Criteria

Inclusion Criteria:

1. Female aged 18 to 75 years (inclusive).
2. Unresectable locally recurrent or metastatic breast cancer.
3. Prior therapy must meet the following: No prior chemotherapy for recurrent/metastatic disease. Must have received at least one prior line of endocrine therapy for recurrent/metastatic disease with disease progression, and the investigator judges that further benefit from endocrine therapy is not possible.
4. Documented radiological disease progression (during or after the most recent therapy).
5. ECOG performance status of 0 or 1.
6. Life expectancy ≥ 12 weeks.
7. At least one extracranial measurable lesion as a target lesion according to RECIST v1.1 criteria.
8. Adequate function of major organs.
9. Pregnancy and contraception: Women of childbearing potential (WOCBP) must agree to use highly effective contraception from study screening until 7 months after the last dose of study drug and agree not to breastfeed; serum pregnancy test result must be negative within 7 days before the first dose.
10. The patient voluntarily participates in this study, signs the informed consent form, has good compliance, and is willing to cooperate with visits and study-related procedures.

Exclusion Criteria:

1. Presence of leptomeningeal metastasis/carcinomatous meningitis, spinal cord compression, or active central nervous system metastases.
2. Patients with only skin or brain lesions as target lesions.
3. History of other malignancies within the past 5 years, except for cured basal cell carcinoma of the skin or carcinoma in situ of the cervix.
4. Presence of carcinomatous lymphangitis, or third-space fluid accumulation that cannot be controlled by methods such as drainage.
5. Prior surgery, chemotherapy, immunotherapy, or macromolecular targeted therapy within 4 weeks before the first dose; prior endocrine therapy, chemotherapy with 5-FU analogs, or radiotherapy within 2 weeks before the first dose; small molecule targeted agents require a washout period of 2 weeks or 5 half-lives; other investigational drugs require a washout period of 4 weeks or 5 half-lives before the first dose.
6. Use of immunosuppressants or systemic corticosteroids for immunosuppressive purposes within 2 weeks before the first dose for therapeutic intent.
7. History of immunodeficiency, including a positive HIV test, other acquired or congenital immunodeficiency diseases, or history of organ transplantation.
8. Clinically significant cardiovascular disease, such as severe/unstable angina, symptomatic congestive heart failure, etc.; clinically significant supraventricular or ventricular arrhythmia requiring treatment or intervention; myocardial infarction or cerebrovascular accident within 6 months before the first dose.
9. Participants with known or suspected interstitial lung disease; other moderate-to-severe pulmonary diseases that may interfere with the detection or management of drug-related pulmonary toxicity and severely affect respiratory function within 3 months before the first dose; and any autoimmune, connective tissue, or inflammatory disorders with pulmonary involvement.
10. Known hereditary or acquired bleeding tendency.
11. Active hepatitis B, hepatitis C, or cirrhosis; or severe infection requiring control with antibiotics, antivirals, or antifungals.
12. Toxicities from prior anti-tumor therapy have not recovered to ≤ Grade 1 (according to NCI-CTCAE v5.0).
13. Any other severe physical or mental illness or laboratory abnormality that may increase the risk associated with study participation, interfere with study results, or any other condition for which the investigator considers the patient unsuitable for participation in this study.

Trial Locations

• Cancer Hospital, Chinese Academy of Medical Sciences, Beijing, Beijing Municipality, China

Frequently Asked Questions

Related Conditions

• Breast Cancer
• Metastatic Breast Cancer
• Locally Recurrent Breast Cancer
• Hormone Receptor-Positive Breast Cancer
• HER2-Low Breast Cancer
• Unresectable Breast Cancer
• Endocrine Therapy Resistance
• Chemotherapy
• Targeted Therapy
• Oncology

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