Relapsed and Refractory Multiple Myeloma (RRMM)Early Phase 1SL4903NCT07234721
SL4903 CAR-T Therapy for Relapsed/Refractory Multiple Myeloma
A Early Phase 1 study testing SL4903 Autologous T-Cell Injection in people with Relapsed and Refractory Multiple Myeloma (RRMM), run by Institute of Hematology & Blood Diseases Hospital, China.
Trial summary
This is a Phase I, single-center, single-arm, open-label clinical study to evaluate the safety, tolerability, and preliminary efficacy of SL4903 autologous T-cell injection (CAR-T cell therapy) in adult patients with relapsed or refractory multiple myeloma (r/r MM) who have failed prior standard therapies. Read more about this study
- Who is it for?
- Ages 18 to 75 years
- Conditions the study is for
- Relapsed and Refractory Multiple Myeloma (RRMM)
- What is being tested?
- SL4903 Autologous T-Cell Injection
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 9 participants
- Where
- No sites listed yet
- Study dates
- 1 Feb 2026to 30 Oct 2028
- Phase
- Early Phase 1
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 75 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Subjects must meet ALL of the following conditions:
- Age 18-75 years; either sex.
- Able to understand the study and provide voluntary written informed consent.
- Histologically and/or cytologically confirmed multiple myeloma according to IMWG 2016 criteria, meeting the following conditions:
- Patients must have received at least one prior line of anti-myeloma therapy, including treatment with proteasome inhibitors (PIs), immunomodulatory drugs (IMiDs), and anti-CD38 monoclonal antibodies, or patients with multiple myeloma refractory to proteasome inhibitors, immunomodulatory drugs, and anti-CD38 monoclonal antibodies;
- Documented evidence of disease progression or failure to achieve complete response (CR) following the last line of therapy, as assessed by the investigator according to IMWG criteria.
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- Measurable disease at screening, defined as meeting one or more of the following criteria:
- Serum M-protein ≥0.5 g/dL
- Urinary M-protein ≥200 mg/24 h
- Abnormal serum FLC ratio (<0.26 or >1.65) with involved FLC ≥10 mg/dL
- Soft tissue extramedullary disease (EMD) identified by radiographic imaging with a longest diameter ≥ 2 cm
- ECOG performance status 0-2.
- Adequate organ function:
- Serum creatinine ≤150 µmol/L or calculated creatinine clearance (Cockcroft-Gault) ≥40 mL/min (may be relaxed for acute MM-related renal impairment at investigator discretion).
- Total bilirubin ≤2×ULN; ALT ≤3×ULN; AST ≤3×ULN.
- Normal diastolic function on echocardiography, LVEF ≥50 %, no significant arrhythmia.
- No active pulmonary infection; oxygen saturation on room air >90 %.
- No contraindication to leukapheresis: Hemoglobin ≥ 60 g/L, platelets ≥ 50 × 10⁹/L, and lymphocytes ≥ 0.3 × 10⁹/L.
- Life expectancy >12 weeks.
- Women of child-bearing potential must have a negative urine pregnancy test and must not be breastfeeding; all men and women with reproductive potential must use effective contraception throughout the study.
Who cannot join
- A subject will be excluded if ANY of the following apply:
- History of severe immediate hypersensitivity to any study drug.
- Central nervous system (CNS) disorders such as epilepsy, paralysis, aphasia, stroke, severe brain injury, dementia, Parkinson's disease, or neuropathy (resolved cases without residual symptoms may be exempted at the investigator's discretion). Active CNS involvement, prior CNS myelomatous disease, or meningeal/spinal cord involvement signs must be excluded.
- Prior traumatic brain injury, cerebrovascular accident, significant cerebral ischemia, or intracranial hemorrhage.
- Concurrent uncontrolled malignancies other than adequately treated cervical carcinoma in situ, basal-cell or squamous-cell skin carcinoma, localized prostate cancer after radical surgery, ductal carcinoma in situ after radical surgery, or thyroid cancer after curative surgery.
- Clinically significant cardiovascular disease, e.g., uncontrolled or symptomatic arrhythmia, congestive heart failure, or NYHA class III/IV cardiac disease; myocardial infarction, coronary angioplasty/stenting, unstable angina, or other clinically relevant cardiac disorders within 12 months before enrollment.
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- Any severe comorbidity or condition judged by the investigator to increase subject risk or interfere with the study, including but not limited to liver cirrhosis or recent major trauma.
- Prior BCMA- and/or GPRC5D-directed CAR-T therapy.
- Allogeneic hematopoietic stem-cell transplantation within 6 months before screening, or any immunosuppressive therapy for graft-versus-host disease during screening.
- Autoimmune disease, immunodeficiency, or need for immunosuppressants (except low-dose corticosteroids).
- Uncontrolled active infection, including but not limited to active tuberculosis; suspected or proven uncontrolled fungal, bacterial, viral, or other infections.
- Live attenuated vaccine within 4 weeks before leukapheresis.
- Active hepatitis (HBV-DNA or HCV-RNA above the lower limit of detection), syphilis infection, congenital or acquired immunodeficiency including HIV, EBV or CMV viremia (DNA above the lower limit of detection).
- History of alcohol abuse, drug abuse, or psychiatric illness.
- Inability to meet the following washout requirements prior to PBMC collection:
- Corticosteroids: no more than 5 mg prednisone (or equivalent) within 72 h.
- Anti-tumor therapies: targeted therapy, epigenetic therapy, investigational drugs/devices-discontinued ≥14 days or ≥5 half-lives (whichever is longer); anti-myeloma monoclonal antibodies-≥21 days; cytotoxic therapy-≥14 days; proteasome inhibitors-≥14 days; immunomodulatory drugs-≥7 days.
- Radiotherapy: completed ≥4 weeks before leukapheresis, except if the radiation field covers ≤5 % of marrow reserves.
- Anti-T-cell antibodies (e.g., alemtuzumab): discontinued ≥8 weeks.
- Any condition judged by the investigator to render the subject unsuitable for enrollment.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: A Phase I Clinical Study of SL4903 Autologous T-Cell Injection for the Treatment of Relapsed/Refractory Multiple Myeloma
This is a Phase I, single-center, single-arm, open-label clinical study to evaluate the safety, tolerability, and preliminary efficacy of SL4903 autologous T-cell injection (CAR-T cell therapy) in adult patients with relapsed or refractory multiple myeloma (r/r MM) who have failed prior standard therapies.
The study employs a "3+3" dose-escalation design with three planned dose levels (1×10⁶, 2×10⁶, and 3×10⁶ CAR+ cells/kg). Approximately 9 to 18 evaluable subjects will be enrolled to determine the maximum tolerated dose (MTD) and recommended Phase II dose (RP2D), and to characterize the safety profile and potential anti-myeloma activity of SL4903.
- Being tested
- SL4903 Autologous T-Cell Injection
- Keywords
- BCMA+GPRC5D, SL4903, Multiple Myeloma, CART
- Medical subject headings
- Recurrence, Multiple Myeloma
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
SL4903 Autologous T-Cell InjectionDrug
Eligible subjects, identified through application of inclusion/exclusion criteria, will be evaluated for tumor type, tumor burden, vital-sign status, and other comprehensive factors before receiving SL4903(1×10⁶ CAR⁺ cells/kg) cellular therapy.
SL4903 Autologous T-Cell InjectionDrug
Eligible subjects, identified through application of inclusion/exclusion criteria, will be evaluated for tumor type, tumor burden, vital-sign status, and other comprehensive factors before receiving SL4903(2×10⁶ CAR⁺ cells/kg) cellular therapy.
SL4903 Autologous T-Cell InjectionDrug
Eligible subjects, identified through application of inclusion/exclusion criteria, will be evaluated for tumor type, tumor burden, vital-sign status, and other comprehensive factors before receiving SL4903(3×10⁶ CAR⁺ cells/kg) cellular therapy.
| Study group | Role | What they receive |
|---|---|---|
| Arm 1: dosage 1×10⁶ CAR⁺ cells/kg | Experimental | In this dosage cohort (1×10⁶ CAR⁺ cells/kg). A total of 3-6 subjects are expected to be enrolled to evaluate the safety and tolerability of SL4903 autologous T-cell injection and to determine the maximum tolerated dose (MTD).
Dose-Escalation Rules
• In the "3 + 3" phase, one subject is enrolled into each dose level and observed for 28 days after cell infusion (the observation period may be prolonged at the investigator's discretion). Receives: Drug: SL4903 Autologous T-Cell Injection |
| Arm 2: dosage 2×10⁶ CAR⁺ cells/kg | Experimental | In this dosage cohort (2×10⁶ CAR⁺ cells/kg). A total of 3-6 subjects are expected to be enrolled to evaluate the safety and tolerability of SL4903 autologous T-cell injection and to determine the maximum tolerated dose (MTD).
Dose-Escalation Rules
• In the "3 + 3" phase, one subject is enrolled into each dose level and observed for 28 days after cell infusion (the observation period may be prolonged at the investigator's discretion). Receives: Drug: SL4903 Autologous T-Cell Injection |
| Arm 3: dosage 3×10⁶ CAR⁺ cells/kg | Experimental | In this dosage cohort (3×10⁶ CAR⁺ cells/kg). A total of 3-6 subjects are expected to be enrolled to evaluate the safety and tolerability of SL4903 autologous T-cell injection and to determine the maximum tolerated dose (MTD).
Dose-Escalation Rules
• In the "3 + 3" phase, one subject is enrolled into each dose level and observed for 28 days after cell infusion (the observation period may be prolonged at the investigator's discretion). Receives: Drug: SL4903 Autologous T-Cell Injection |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number and incidence rate of adverse events following intravenous infusion of SL4903 cells
Within one month after cell infusion, all documented adverse events-including cytokine-release syndrome and neurotoxicity-will be analyzed for incidence, frequency, and severity to evaluate the safety of SL4903 and to determine the maximum tolerated dose (MTD).
Measured: one month
Secondary outcomes (12)
Overall response rate (ORR)
Percentage of subjects who achieved partial response (PR) or better according to IMWG Uniform Response Criteria for Multiple Myeloma
Measured: at 3, 6, 9, 12, 18, and 24-month after CAR-T infusion
Complete response rate (CRR)
Percentage of subjects who achieved complete response (CR) or stringent complete response (sCR) according to IMWG Uniform Response Criteria for Multiple Myeloma
Measured: at 3, 6, 9, 12, 18, and 24-month after CAR-T infusion
Time to Response (TTR)
Time from SL4903 CAR-T infusion to first documentation of response evaluated by investigators
Measured: Minimum of 2 years post SL4903 CAR-T infusion
Progression-free Survival (PFS)
Time from SL4903 CAR-T infusion to first documentation of progressive disease (PD), or death due to any cause, whichever occurs first
Measured: Minimum of 2 years post SL4903 CAR-T infusion
Duration of Response (DOR)
Time from first response evaluated by investigators to disease progression or death from any cause
Measured: Minimum of 2 years post SL4903 CAR-T infusion
Overall Survival (OS)
Time from SL4903 CAR-T infusion to time of death due to any cause
Measured: Minimum of 2 years post SL4903 CAR-T infusion
Minimal Residual Disease (MRD) negative rate
Proportion of subjects who achieved MRD negative
Measured: at 3, 6, 9, 12, 18, and 24-month after CAR-T infusion
Pharmacokinetic (Cmax)
Testing CARgene copies and CAR-T/T% in peripheral blood by qPCR and Flow cytometry，then analysising the Cmax.
Measured: at day0 to day28 after CAR-T infusion
Pharmacokinetic (Tmax)
Testing CARgene copies and CAR-T/T% in peripheral blood by qPCR and Flow cytometry，then analysising the time to peak (Tmax).
Measured: at day0 to day28 after CAR-T infusion
Pharmacokinetic (AUCday0~28)
Testing CARgene copies and CAR-T/T% in peripheral blood by qPCR and Flow cytometry，then analysising the AUC(day0~28).
Measured: at day0 to day28 after CAR-T infusion
proportion of peripheral plasma cells
The proportion of peripheral plasma cells at various time points
Measured: at day0 , day7, day10, day14 and day28 after CAR-T infusion
cytokines level
The release amount of cytokines at various time points
Measured: at day0 , day7, day10, day14 and day28 after CAR-T infusion
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Nov 2025
- Study start1 Feb 2026 (estimated)
- Primary completion20 Mar 2028 (estimated)
- Study completion30 Oct 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Relapsed and Refractory Multiple Myeloma (RRMM)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Early Phase 1
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Model description
- ARM 1: dosage 1\*10\^6 CART cells/Kg; ARM 2: dosage 2\*10\^6 CART cells/Kg; ARM 3: dosage 3\*10\^6 CART cells/Kg
- Masking
- None (open label)
- Enrolment
- 9 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Institute of Hematology & Blood Diseases Hospital, China
- Sponsor type
- University, hospital or other
- Collaborators
- Hebei Senlang Biotechnology Inc., Ltd.
- Responsible party
- Sponsor
- Investigators
- An, Principal investigator, Institute of Hematology and Blood Diseases Hospital Chinese Academy of Medical Sciences,Tianjin
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07234721
- Sponsor's protocol ID
- IIT2025098
- Acronym
- SL4903
- Status last verified
- Jan 2026
- First submitted
- 16 Sep 2025
- Last updated
- 10 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No