A Phase 1 interventional study of P-BCMA-ALLO1 CAR-T cells and Rimiducid in Multiple Myeloma, sponsored by Poseida Therapeutics, Inc.. Active, not recruiting at 23 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-04-24.
Sponsored by Poseida Therapeutics, Inc. (part of Hoffmann-La Roche) · Phase 1, Interventional, and Treatment
Phase 1 study comprised of open-label, dose escalation, multiple cohorts of P-BCMA-ALLO1 allogeneic T stem cell memory (Tscm) CAR-T cells in subjects with relapsed / refractory Multiple Myeloma (RRMM).
Phase 1/1b study: Phase 1 Part 1 is a weight-based dose escalation following a 3+3 design of dose-escalating cohorts. Phase 1 Part 2 includes administration at fixed doses. After enrollment, subjects may receive a lymphodepletion therapy regimen before administration of allogeneic CAR-T cells, administered as a single or multiple dose(s). Treated subjects will undergo serial measurements of safety, tolerability and response. Rimiducid may be administered as indicated. Phase 1b of the study will undergo further expansion of cohorts/arms from Phase 1 Parts 1 or 2 or an intermediate dose between cohort levels.
3,760 studies on the registry are indexed under Multiple Myeloma; 769 are open to participants now.
This study's planned enrollment of 275 is above the median of 41 across 3,005 interventional studies indexed under Multiple Myeloma.
Browse Multiple Myeloma studies →Poseida Therapeutics, Inc. is the lead sponsor of 6 studies on the registry; none are open to participants now.
First submitted before Poseida Therapeutics, Inc. became part of Hoffmann-La Roche.
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.
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.
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.
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
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.
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.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
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.
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
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.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).
Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
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.
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.
Allogeneic and autologous transplant
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
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.
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.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
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.
NYHA class (heart failure)
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
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.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Brain metastases
Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).
Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Live vaccines
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Single weight-based IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen S. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Single weight-based IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen F. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Single weight-based IV administration of P-BCMA-ALLO1. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Single weight-based IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen P1. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Single weight-based IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen P2. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Single weight-based IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen R. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Single weight-based IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen RS. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Cyclic weight-based IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen C. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Single fixed dose IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen S, P1, P1.5 or P2. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Single fixed dose IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen S, P1, P1.5 or P2. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Single weight-based IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen P1.5. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Single weight-based IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen RP1. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Single weight-based IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen RP1.5. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Single weight-based IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen RP2. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Cyclic weight-based IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen CP1. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Cyclic weight-based IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen CP1.5. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Cyclic weight-based IV administration of P-BCMA-ALLO1 following conditioning chemotherapy regimen CP2. Rimiducid may be administered as indicated.
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid
Single weight based IV administration of P-BCMA-ALLO1 and methotrexate following conditioning chemotherapy regimen MP1.5 Rimiducid may be administered as indicated
Biological: P-BCMA-ALLO1 CAR-T cells · Drug: Rimiducid · Drug: Methotrexate
Allogeneic BCMA-targeted chimeric antigen receptor (CAR) T-cell therapy
Safety switch activator
Anti-metabolite
Phase 1 Part 1: Assess the safety and maximum tolerated dose (MTD) of P-BCMA-ALLO1 based on dose limiting toxicities (DLT)
Rate of dose limiting toxicities (DLT)
Time frame: Baseline through Day 28
Phase 1 Part 2: Assess the safety and tolerability of P-BCMA-ALLO1 when administered as a fixed dose of cells.
Frequency and severity of adverse events, including cytokine release syndrome.
Time frame: Baseline through 36 months
Phase 1b: The effect of cell dose and study arm
Overall response rate (ORR) based on International Myeloma Working Group (IMWG) uniform response criteria
Time frame: Baseline through 36 months
The safety of P-BCMA-ALLO1
Incidence and severity of treatment-emergent adverse events
Time frame: Baseline through 15 years
The anti-myeloma effect of P-BCMA-ALLO1 (ORR) in Phase 1 Parts 1 and 2
According to the International Myeloma Working Group (IMWG) Uniform Response Criteria for Multiple Myeloma: Overall Response Rate (ORR) - Percentage of patients with complete response (CR), very good partial response (VGPR), or partial response (PR)
Time frame: Baseline through 15 years
Safety and Efficacy (anti-myeloma effect) will be used to guide the selection of RP2D
According to the International Myeloma Working Group (IMWG) Uniform Response Criteria for Multiple Myeloma: Time to Response (TTR) - Time to complete response (CR), very good partial response (VGPR), or partial response (PR) to progressive disease, Overall response rate (ORR), Duration of response (DOR), Progression free survival (PFS), and Overall survival (OS)
Time frame: Baseline through 15 years
Plan to share: No
Started May 2022 (actual). Primary completion is estimated for Mar 2029, 82 months after the start.
Of 212 industry-sponsored phase 1 interventional studies under Multiple Myeloma, half reached primary completion within 43 months of starting (the median), counting those still running; a quarter within 27 and three quarters within 71. This study's planned 82 months is above that.
Counting every sponsor, half of 413 studies reached it within 50 months; a quarter within 33 and three quarters within 75.
How these figures are worked out, and which studies are left out of them.
This study is active, not recruiting, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.
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