SMP-656 for HER2-Positive Advanced Breast Cancer (NCT07726342) | Clinical Trial Compass
Not Yet RecruitingPhase 2
SMP-656 for HER2-Positive Advanced Breast Cancer
China60 participantsStarted 2026-07-16
Plain-language summary
The goal of this clinical trial is to learn if single-agent SMP-656 works to treat patients with HER2-positive locally advanced or metastatic breast cancer who have progressed after prior HER2-targeted topoisomerase inhibitor antibody-drug conjugate (ADC) treatment. It will also evaluate the safety of SMP-656 and identify the optimal dose for future trials. The main questions it aims to answer are:
What is the objective tumor response rate (DOR, PFS, DCR, OS) of two different dose regimens of intravenous SMP-656? What are the side effects and safety risks of these two SMP-656 dose regimens? Which dose level achieves the best balance of anti-cancer activity and tolerability? This is a randomized, open-label, dose-optimization Phase II clinical trial. Participants will be randomly assigned 1:1 to receive one of two fixed doses of SMP-656 given intravenously once every 3 weeks.
Participants will:
Complete screening tests within 28 days before the first SMP-656 infusion to confirm eligibility Receive study treatment every 3 weeks until cancer progression, intolerable side effects, withdrawal, or other stopping criteria Have regular tumor imaging scans, physical exams, vital sign checks, and blood tests to monitor tumor response and safety Attend a safety follow-up visit 30 days after the last dose of SMP-656 Complete longer-term survival follow-up after the 30-day safety check Provide optional blood and tumor tissue samples for additional research studies
Who can participate
Age range
18 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
. Voluntarily participate in this clinical trial, understand and comply with study procedures, and provide written informed consent voluntarily;
. Female patients aged ≥ 18 years at the time of signing the informed consent form;
. Patients with histologically or cytologically confirmed unresectable HER2-positive locally advanced or metastatic breast cancer, regardless of hormone receptor (HR) status;
. HER2-positive status confirmed by testing at the study center or an accredited laboratory, where HER2 positivity is defined as IHC 3+, or IHC 2+ with positive fluorescence in situ hybridization (FISH+) results;
. Patients with HER2-positive locally advanced or metastatic breast cancer who have received prior treatment with one TOP inhibitor ADC targeting HER2 (e.g., DS-8201 and other ADCs with topoisomerase inhibitor payloads), and have experienced disease progression after no more than three lines of standard therapy for recurrent or metastatic disease; 1) Endocrine monotherapy is excluded from the abovementioned standard therapy lines; 2) Disease recurrence occurring within 12 months following neoadjuvant or adjuvant chemotherapy will be regarded as progression after first-line standard therapy;
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Objective Response Rate (ORR) assessed by Independent Review Committee (IRC)
Timeframe: From the date of first dose to the date of first radiological documentation of disease progression or death, whichever occurs first (up to 24 months)
2
Recommended Dose in Pivotal Clinical Trials
Timeframe: Through study completion, up to 24 months from first dose
. Have at least one measurable target lesion per the Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) ;
. ECOG performance status 0-1;
. Expected survival ≥ 3 months;
Exclusion criteria
. Patients with inflammatory breast cancer;
. Have received eribulin in prior lines of therapy;
. Have received prior treatment with ADCs carrying tubulin inhibitor payloads for recurrent or metastatic disease;
. Prior anti-tumor therapy consisting of utidelone or vinca alkaloids as the last regimen;
. Patients with a known history of severe hypersensitivity to inetetamab, SMP-656, or any of their excipients;
. Patients with meningeal metastases;
. Patients with active central nervous system (CNS) metastases are excluded, with the following exception: symptomatic CNS metastases limited to supratentorial region and/or cerebellum (i.e., no midbrain, pons, medulla oblongata or spinal cord metastases) that have received local therapy, with neurological symptoms stabilized for at least 2 weeks prior to the first dose of investigational product, and no requirement for steroid therapy or receiving prednisone ≤10 mg/day (or equivalent corticosteroids) ;
. Patients diagnosed with any other malignancy (other than the study tumor type) within 5 years prior to the first dose of the investigational product, except curatively treated localized malignancies such as basal cell carcinoma of the skin;