A Phase 1 interventional study of SL4903 Injection (BCMA/GPRC5D Dual-Target Autologous CAR-T Cell Injection) in Multiple Myeloma; Relapsed/Refractory Multiple Myeloma, sponsored by Liping Dou. Not yet recruiting at 1 site in China. Open to participants aged 18 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-11-10.
Sponsored by Liping Dou · Phase 1, Interventional, and Treatment
This is a single-center, open-label, single-arm, investigator-initiated clinical study to evaluate the safety, tolerability, and preliminary efficacy of SL4903, a BCMA/GPRC5D dual-target autologous CAR-T cell injection, in patients with relapsed or refractory multiple myeloma (R/R MM) whose clonal plasma cells are positive for BCMA and/or GPRC5D. After leukapheresis, participants receive lymphodepleting conditioning (fludarabine 30 mg/m\^2/day plus cyclophosphamide 500 mg/m\^2/day on Days -5 to -3), followed by a single intravenous infusion of SL4903 at a dose of 1×10\^6 CAR-positive cells/kg; bridging therapy (e.g., immunomodulatory drugs or anti-CD38 monoclonal antibody) is permitted between leukapheresis and conditioning at the investigator's discretion. Treatment-emergent adverse events, including cytokine release syndrome (CRS), neurotoxicity, hematologic toxicity, and organ toxicity, will be assessed within 3 months after infusion. Preliminary antitumor activity will be evaluated according to the 2016 International Myeloma Working Group (IMWG) criteria, including objective response rate (ORR), complete response rate (CRR), time to response (TTR), duration of response (DOR), progression-free survival (PFS), overall survival (OS), and measurable residual disease (MRD) negativity rate. Pharmacokinetics (Cmax, Tmax, persistence, and AUCd0-28 of CAR-T cells in peripheral blood by flow cytometry and qPCR) and pharmacodynamics (peripheral blood plasma cell proportion and cytokine levels) will also be evaluated. Participants will be followed for safety and efficacy for up to 2 years after cell therapy.
This is a single-center, single-arm, open-label, investigator-initiated clinical study of SL4903 autologous T-cell injection in adults with R/R MM. SL4903 is an autologous CAR-T cell product in which the CAR comprises, in order, a GPRC5D-targeting nanobody (VHH1), a BCMA-targeting nanobody (VHH2), a CD8 hinge region, a CD8 transmembrane domain, a 4-1BB costimulatory domain, and a CD3-zeta signaling domain; autologous peripheral blood mononuclear cells are collected by leukapheresis (approximately 80-120 mL), transduced ex vivo with a lentiviral vector, and expanded over a manufacturing period of approximately 7-8 days. Participants receive lymphodepleting conditioning with fludarabine (30 mg/m\^2/day) and cyclophosphamide (500 mg/m\^2/day) on Days -5 to -3, which may be adjusted at the investigator's discretion, followed by a single intravenous infusion of SL4903 at 1×10\^6 CAR-positive cells/kg on Day 0. Planned enrollment is 20 participants; enrollment accounts for potential CAR-T manufacturing failure or rapid disease progression that may preclude infusion. Safety assessments include adverse events and serious adverse events graded per NCI CTCAE v5.0, with CRS and immune effector cell-associated neurotoxicity syndrome (ICANS) graded per the ASTCT consensus criteria; infection, hematologic toxicity, organ toxicity, hemophagocytic lymphohistiocytosis/macrophage activation syndrome (HLH/MAS), and tumor lysis syndrome (TLS) are also monitored. Disease response is assessed per the 2016 IMWG criteria at baseline, Day 28, and Months 2, 3, 6, 12, 18, and 24, including serum/urine M-protein studies, serum free light chains, bone marrow examination with flow cytometry/MRD, and imaging (preferably PET-CT) for extramedullary disease. Pharmacokinetic assessments include CAR-T cell expansion in peripheral blood by flow cytometry and qPCR (Cmax, Tmax, in vivo persistence, and AUCd0-28); pharmacodynamic assessments include peripheral blood plasma cell proportion/count and cytokine quantification (at least IL-6, IL-2, IL-10, IFN-gamma, and TNF-alpha).
3,760 studies on the registry are indexed under Multiple Myeloma; 769 are open to participants now.
This study's planned enrollment of 20 is below the median of 41 across 3,005 interventional studies indexed under Multiple Myeloma.
Browse Multiple Myeloma studies →Liping Dou is the lead sponsor of 13 studies on the registry; 11 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Clonal plasma cells positive for BCMA and/or GPRC5D by flow cytometry or immunohistochemistry.
Prior treatment with at least 3 drug classes (proteasome inhibitors [PIs], immunomodulatory drugs [IMiDs], and an anti-CD38 monoclonal antibody), with best response less than partial response (PR) or disease progression after achieving PR or better.
(estimated by the Cockcroft-Gault formula) ≥60 mL/min or serum creatinine ≤1.5 × the (ULN); Serum (ALT) and aspartate aminotransferase (AST)≤2.5×upper limit of normal (ULN), total ≤1.5×ULN; Cardiac ≥50%, no pericardial effusion on echocardiography, and no significant abnormalities on (ECG); No pleural effusion, and oxygen saturation >92% on room air at baseline.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Relapsed and refractory
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Life expectancy
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Creatinine clearance (CrCl)
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
LVEF (left ventricular ejection fraction)
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECG (electrocardiogram)
A recording of the heart’s electrical activity, taken with stickers on the chest, arms and legs. It takes a few minutes and does not hurt.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Reproductive potential
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Washout period
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
SL4903 Treatment Group - after leukapheresis and lymphodepleting conditioning (fludarabine 30 mg/m\^2/day plus cyclophosphamide 500 mg/m\^2/day on Days -5 to -3), participants receive a single intravenous infusion of SL4903 autologous T-cell injection at a dose of 1 x 10\^6 CAR-positive cells/kg. Bridging therapy (e.g., immunomodulatory drugs or anti-CD38 monoclonal antibody) may be given between leukapheresis and conditioning at the investigator's discretion.
Drug: SL4903 Injection (BCMA/GPRC5D Dual-Target Autologous CAR-T Cell Injection)
SL4903 is an investigational autologous dual-target CAR T-cell therapy (lentiviral vector-based) directed against BCMA and GPRC5D, for patients with relapsed or refractory multiple myeloma whose clonal plasma cells are positive for BCMA and/or GPRC5D. The CAR comprises a GPRC5D-targeting nanobody (VHH1), a BCMA-targeting nanobody (VHH2), a CD8 hinge region, a CD8 transmembrane domain, a 4-1BB costimulatory domain, and a CD3-zeta signaling domain. After leukapheresis and lymphodepleting conditioning (fludarabine plus cyclophosphamide), participants receive a single intravenous infusion of SL4903 at 1×10\^6 CAR-positive cells/kg.
Also known as: SL4903; BCMA-GPRC5D CAR-T injection
Adverse Events
AEs are graded per NCI CTCAE v5.0
Time frame: From SL4903 infusion through 3 months after infusion; long-term safety follow-up continues through 12 months
Cytokine Release Syndrome
Cytokine release syndrome (CRS) is graded according to the ASTCT consensus criteria.
Time frame: From SL4903 infusion through 3 months after infusion; long-term safety follow-up continues through 12 months
Immune Effector Cell-associated Neurotoxicity Syndrome
Immune effector cell-associated neurotoxicity syndrome (ICANS) is graded according to the ASTCT consensus criteria.
Time frame: From SL4903 infusion through 3 months after infusion; long-term safety follow-up continues through 12 months
Objective Response Rate
The proportion of participants achieving a partial response or better (ORR), assessed by the investigator according to the 2016 International Myeloma Working Group (IMWG) criteria.
Time frame: At Day 28 and Months 2, 3, 6, 12, 18, and 24 after SL4903 infusion
Complete Response Rate
The proportion of participants achieving a complete response (CR) or stringent complete response (sCR), per the 2016 IMWG criteria.
Time frame: At Day 28 and Months 2, 3, 6, 12, 18, and 24 after SL4903 infusion
Time to Response and Duration of Response
Time to response (TTR), defined as the time from SL4903 infusion to first documented response, and duration of response (DOR), defined as the time from first documented response to disease progression or death, per the 2016 IMWG criteria.
Time frame: From SL4903 infusion through 24 months after treatment
Progression-Free Survival
Progression-free survival (PFS), defined as the time from SL4903 infusion to disease progression or death from any cause, whichever occurs first, per the 2016 IMWG criteria; PFS rates at 6, 9, 12, 18, and 24 months will also be estimated.
Time frame: From SL4903 infusion through 24 months after treatment
Overall Survival
Overall survival (OS), defined as the time from SL4903 infusion to death from any cause; OS rates at 6, 9, 12, 18, and 24 months will also be estimated. Participants who are alive at the last follow-up will be censored on the date of their last known survival status.
Time frame: From SL4903 infusion through 24 months after treatment
Measurable Residual Disease (MRD) Negativity Rate
The proportion of participants achieving MRD negativity in bone marrow, assessed by flow cytometry, among responding participants.
Time frame: At Day 28 and Months 2, 3, 6, 12, 18, and 24 after SL4903 infusion
Peak Expansion of SL4903 CAR-T Cells in Peripheral Blood
Peak expansion of SL4903 CAR-T cells in peripheral blood (Cmax, measured by both flow cytometry and qPCR),
Time frame: Through Day 28 for AUCd0-28, Cmax, and Tmax; CAR-T persistence through 24 months after infusion
Time to Peak Expansion
Time to Peak Expansion
Time frame: Through Day 28 for AUCd0-28, Cmax, and Tmax; CAR-T persistence through 24 months after infusion
Area Under The Gene-copy Expansion Curve from Day 0 to Day 28
in vivo persistence of CAR-T cells, and the area under the gene-copy expansion curve from Day 0 to Day 28 (AUCd0-28).
Time frame: Through Day 28 for AUCd0-28, Cmax, and Tmax; CAR-T persistence through 24 months after infusion
Pharmacodynamic Markers (Exploratory)
Proportion and absolute count of plasma cells in peripheral blood by flow cytometry, and peripheral blood cytokine levels (at least IL-6, IL-2, IL-10, IFN-gamma, and TNF-alpha) at prespecified time points.
Time frame: Through 24 months after SL4903 infusion
Plan to share: No
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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