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
Overview
- Phase
- Phase 1
- Intervention
- Not specified
- Conditions
- End Stage Kidney Disease
- Sponsor
- University of California, Los Angeles
- Enrollment
- 10
- Locations
- 1
- Primary Endpoint
- Incidence of successful discontinuation of immunosuppression
- Status
- Recruiting
- Last Updated
- 5 months ago
Overview
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determine if patients with a pre-existing, well-functioning kidney transplant from a HLA-identical living donor can be withdrawn from immunosuppressive medications without compromising allograft function through hematopoietic stem cell (HPSC) infusion from the same donor.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).
Investigators
Jeffrey Veale, MD
Professor
University of California, Los Angeles
Eligibility Criteria
Inclusion Criteria
- •Males and females ages 18 years and older with a pre- existing kidney transplant from an HLA-matched living donor.
- •Pre-existing living kidney transplant must be within 3 months to 5 years from date of scheduled HPSC infusion.
- •No history of rejection with current HLA matched kidney transplant.
- •Recipient is without post-transplant major complications, including de novo malignancy, active infection or rejection.
- •Stable renal function determined per investigator discretion.
- •Agreement to participate in the study and ability to give informed consent.
- •Meets institutional criteria for HSPC infusion.
- •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.
- •No known contraindication to administration of rATG or radiation.
- •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.
Exclusion Criteria
- •Donor is identical twin.
- •Major ABO incompatibility with donor
- •Positive HLA Donor-Specific Antibody (DSA)
- •History of multi-organ transplantation
- •History of rejection with current HLA-matched kidney transplant
- •Known allergy to rabbit proteins
- •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.
- •History of active malignancy within the past 5 years with the exception:
- •Low risk cancer on active surveillance
Outcomes
Primary Outcomes
Incidence of successful discontinuation of immunosuppression
Time Frame: 12 months
To 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 Outcomes
- Graft survival(24 months)
- Incidence of allograft rejection(48 months)