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Delayed Immunological Tolerance in Patients With Well-functioning Pre-existing HLA-matched Kidney Transplants

A Single-armed, Unblinded, Non-randomized Feasibility Study of Hematopoietic Stem Cell Infusion Following a Conditioning Regimen of Total Lymphoid Irradiation (TLI) and Anti-thymocyte Globulin (ATG) in Patients With a Pre-existing, Well-functioning HLA-matched Kidney Transplant

Status
Recruiting
Phases
Phase 1
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT05525507
Enrollment
10
Registered
2022-09-01
Start date
2022-12-21
Completion date
2026-12-31
Last updated
2025-11-26

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Chronic Kidney Diseases, End Stage Kidney Disease, Immunological Tolerance, Kidney Transplant Failure and Rejection

Keywords

immunological tolerance, kidney transplant, tolerance, end stage kidney disease, end stage renal disease, chronic kidney disease

Brief summary

The study seeks to determine if patients with a pre-existing, well-functioning kidney transplant from a HLA-identical living donor can be withdrawn from immunosuppressive medications without compromising allograft function through hematopoietic stem cell (HPSC) infusion from the same donor. HPSC infusion will be preceded by a conditioning regimen of total lymphoid irradiation (TLI) and rabbit anti-thymocyte globulin (rATG).

Detailed description

Immunological tolerance through combined kidney and HPSC transplant has been demonstrated at few centers of excellence within the United States. The ultimate aim of these protocols is to liberate patients from lifelong immunosuppression. Thus far, protocols have been limited to HLA-identical donor recipient pairs, undergoing simultaneous kidney transplant and HPSC infusion. In all protocols, the recipient undergoes a conditioning regimen to optimize engraftment. Our protocol employs a conditioning regimen of TLI and ATG. There are many more patients with pre-existing well-functioning HLA-identical kidney transplants than those who present de novo for participation in tolerance trials. Despite this, post hoc tolerance induction through HPSC infusion in patients with a pre-existing kidney transplant has not yet been performed. Given the demonstrated success of tolerance protocols in simultaneous haploidentical kidney and HPSC transplant, the next logical step is to demonstrate that tolerance can be induced in the much greater subset of patients with pre-existing kidney transplants. This study employs an established protocol for immunological tolerance induction in patients with a pre-existing, well- functioning kidney transplant from their haploidentical donor. These patients will undergo a conditioning with TLI and ATG, followed by infusion of HPSC from the same HLA-identical donor that provided the original kidney. The Investigators call this process retroactive tolerance induction. The investigators will evaluate whether recipients can be withdrawn from immunosuppressive drugs without compromising allograft function. At serial time points, (1) graft function will be monitored, and (2) chimerism will be measured in recipient whole blood and white blood cell subsets. Weaning of tacrolimus will begin at 6 months, with a goal of drug discontinuation within 12 months if the following conditions are met: (1) chimerism (defined as ≥1% donor type cells among the T cells, B cells, NK cells, and granulocytes) is detectable for at least 180 days after CD34+ and CD3+ cell infusion, (2) stable graft function (defined as eGFR \>30 mL/min and no greater than sustained 30% change over 3 months from baseline) without clinical rejection episodes is maintained, and (3) there is no evidence of graft vs. host disease (GVHD).

Interventions

COMBINATION_PRODUCTConditioning and Stem cell infusion

Patients will undergo a conditioning with TLI and ATG, followed by infusion of hematopoietic stem cells from the same HLA-identical donor that provided the original kidney

Sponsors

University of California, Los Angeles
Lead SponsorOTHER

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes

Inclusion criteria

Recipient Inclusion Criteria: 1. Males and females ages 18 years and older with a pre- existing kidney transplant from an HLA-matched living donor. 2. Pre-existing living kidney transplant must be within 3 months to 5 years from date of scheduled HPSC infusion. 3. No history of rejection with current HLA matched kidney transplant. 4. Recipient is without post-transplant major complications, including de novo malignancy, active infection or rejection. 5. Stable renal function determined per investigator discretion. 6. Agreement to participate in the study and ability to give informed consent. 7. Meets institutional criteria for HSPC infusion. 8. Resides or is willing to stay within 3 hours distance from UCLA Medical Center by ground transportation for the first three to six months of the trial at the physician's discretion. 9. No known contraindication to administration of rATG or radiation. 10. If participant is a female of reproductive potential (i.e., no documented absence of ovaries or uterus, history of tubal ligation, or post-menopausal status) participant must be confirmed not pregnant by a serum or urine pregnancy test) and must agree to practice a reliable form of contraception including hormonal treatments, barrier methods or intrauterine device for at least 12 months post-transplant. 11. Karnofsky Performance Score (KPS) ≥ 70. 12. Adequate cardiac function defined as left ventricular ejection fraction (LVEF) ≥ 40% by MUGA (Multi Gated Acquisition) scan or echocardiogram. 13. Adequate liver function defined as total bilirubin ≤ 1.5 times the upper limit of normal and AST/ALT ≤ 2.0 times the upper limit of normal. 14. Adequate social support based on evaluation by the UCLA bone marrow and/or renal transplant team. Recipient

Exclusion criteria

1. Donor is identical twin. 2. Major ABO incompatibility with donor 3. Positive HLA Donor-Specific Antibody (DSA) 4. History of multi-organ transplantation 5. History of rejection with current HLA-matched kidney transplant 6. Known allergy to rabbit proteins 7. History of post-transplant major complications, including de novo malignancy, active/chronic infection or rejection, with the exception of low risk, early-stage malignancy with ≥90% 5-year survival not receiving chemotherapy or immunotherapy and non-melanomatous skin cancer. 8. History of active malignancy within the past 5 years with the exception: 1. Low risk cancer on active surveillance 2. Malignancy treated with curative intent with no known active disease \>2 years before the first dose of study treatment and of low potential risk for recurrence 3. Adequately treated non-melanoma skin cancer or lentigo maligna without evidence of disease 4. Adequately treated carcinoma in situ without evidence of disease (e.g., cervical cancer in situ, and DCIS) 9. Worsening renal functioning over preceding 3-month interval determined per investigator discretion. 10. Pregnant (confirmed by urine or serum pregnancy test) or lactating. 11. Leukopenia (with a white blood cell count \< 3,000/µL) or thrombocytopenia (with a platelet count \< 70,000/µL). 12. EBV, CMV and BK PCR negative at time of HPSC infusion is preferred, but if they have had a history of + CMV/BK PCR, it should be resolved by 3 months. 13. Active bacterial, fungal, mycobacterial, or viral infection (including active hepatitis B and/or C). 14. Seropositivity for HIV 1 or 2 by 4th generation serum antibody/antigen testing, or HTLV I or II by serum antibody testing. 15. Renal disease with high risk of recurrence (i.e., focal segmental glomerulosclerosis). 16. Advanced hepatic fibrosis or cirrhosis secondary to hepatitis B and/or C diagnosis. 17. Uncontrolled intercurrent illness including, but not limited to, symptomatic congestive heart failure, unstable angina pectoris, or cardiac arrhythmia; active extra-renal autoimmune disease requiring immunosuppression. 18. Active extra-renal autoimmune disease requiring immunosuppression. 19. Neuropsychiatric illness that precludes the ability to give informed consent and/or places the participant as high risk for non-compliance with the safety monitoring requirements of the study. 20. May not have received other immunomodulatory agents, including but not limited to tumor necrosis factor inhibitors within six months of the study treatment. Use of corticosteroids prescribed for a time-limited indication (\</= 4 weeks) and stopped at least 4 weeks before the kidney transplant is acceptable. 21. May not have received immunotherapy drugs such as immune checkpoint inhibitors (e.g. pembrolizumab, nivolumab, and ipilimumab), tumor necrosis factor inhibitors, rituximab, and interleukin-2 within six months of the study treatment. 22. Current or active abuse of alcohol and/or drugs within last 6 months. 23. Body Mass Index (BMI) ≥ 40. Donor Inclusion Criteria: 1. HLA-matched sibling on high-resolution HLA typing who a. is ≥18 years of age. 2. Must meet institutional criteria for HSPC transplant donation. 3. Medically fit to tolerate peripheral blood apheresis, including weighing ≥110 pounds, hemoglobin ≥11, white blood cell count ≥ 3,000/µL, and platelets ≥ 100,000/µL. 4. Serum creatinine as expected post-kidney donation and coagulation parameter studies; or, if abnormal, the changes are not considered clinically significant. Donor

Design outcomes

Primary

MeasureTime frameDescription
Incidence of successful discontinuation of immunosuppression12 monthsTo determine whether patients with pre-existing kidney transplants from a haploidentical living donor can be withdrawn from immunosuppressive drugs while maintaining stable graft function within 12 months of hematopoietic stem cell infusion from the same HLA-identical living donor, preceded by conditioning with TLI and ATG.

Secondary

MeasureTime frameDescription
Incidence of allograft rejection48 monthsTo determine the percentage of subjects with graft rejection within 48 months post-HPSC infusion defined as (1) meets Banff criteria for rejection on biopsy performed to confirm clinical suspicion of rejection or (2) clinical suspicion of rejection demonstrating response to corticosteroids in absence of biopsy when confirmatory biopsy contraindicated or declined.
Graft survival24 monthsTo determine graft survival within the first 24 months post-HPSC infusion.

Countries

United States

Contacts

Primary ContactRuth Wynne Jones
rwynnejones@mednet.ucla.edu424-402-9564
Backup ContactJenny Lester, MPH
jlester@mednet.ucla.edu310-794-9728

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026