SMP-656 for HER2-Positive Advanced Breast Cancer
Trial statusNot yet recruiting
Trial phasePhase 2
Trial typeInterventional
Biological sexAll
Age18+
SponsorChengdu SciMount Pharmatech Co., Ltd.
About this trial
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
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
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;
Disqualifiers
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;
Trial design
Design model
Parallel
Treatments tested in this trial
SMP-656 Injection
DrugSMP-656 injection administered via intravenous infusion at a dose of 2.0 mg/kg once every 3 weeks (Q3W). Treatment continues until disease progression, intolerable toxicity, voluntary withdrawal, death, or trial termination.
SMP-656 Injection
DrugSMP-656 injection administered via intravenous infusion at a dose of 2.2 mg/kg once every 3 weeks (Q3W). Treatment continues until disease progression, intolerable toxicity, voluntary withdrawal, death, or trial termination.
Treatment groups
60 Participants
are divided into 2 treatment groupsGroup A: SMP-656 2.0 mg/kgExperimental treatment 1 intervention
Group B: SMP-656 2.2 mg/kgExperimental treatment 1 intervention
Trial outcomes
Primary outcomes
1
Objective Response Rate (ORR) assessed by Independent Review Committee (IRC)
ORR is the percentage of evaluable patients with an IRC-assessed response of complete response (CR) or partial response (PR) per RECIST v1.1.
Time frame
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
Determination of pivotal trial recommended dose based on drug exposure, efficacy, and safety profiles across different dose levels.
Time frame
Through study completion, up to 24 months from first doseSecondary outcomes
1
ORR assessed by Investigators
Investigator-assessed ORR is the percentage of evaluable patients with a confirmed investigator-assessed response of CR or PR per RECIST v1.1.
Time frame
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
Duration of Response (DOR)
DOR is the time from the date of first documented confirmed objective response (CR or PR per RECIST v1.1) until the date of disease progression or death.
Time frame
From first confirmed objective response (CR/PR) up to 24 months from first dose3
Progression-Free Survival (PFS)
PFS is the time from the date of first dose until the date of objective radiographic disease progression or death (by any cause in the absence of progression).
Time frame
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)4
Disease Control Rate (DCR)
DCR is the investigator-assessed percentage of evaluable participants with confirmed CR (complete response), PR (partial response), or SD (stable disease) per RECIST v1.1.
Time frame
Up to 24 months from first doseOther outcomes
1
Genomic and Microenvironment Molecular Alterations Associated With SMP-656 Resistance
Baseline and post-treatment genomic, circulating biomarker and tissue spatial microenvironment profiles of blood and tumor samples, including ctDNA, circulating proteins, exosomes, and tissue microenvironment features.
Time frame
Baseline and end-of-treatment (EOT) visit. EOT sampling is performed within 7 days after treatment discontinuation and prior to any new antitumor therapy, up to 24 months from first dose.2
Multi-Omics Biomarker Profiles Correlated With Clinical Efficacy and Prognosis
Multi-omics profiles of blood and tumor samples, including ctDNA, plasma proteomics, single-exosome profiling, tissue spatial transcriptomics/proteomics, and tissue genomic features.
Time frame
Baseline and EOT visit. EOT sampling is performed within 7 days after treatment discontinuation and prior to any new antitumor therapy, up to 24 months from first dose.Sponsors and contacts
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Source ClinicalTrials.gov
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