Inducing tolerance in kidney transplant patients through mixed chimerism

Renal Allograft Tolerance Through Mixed Chimerism - SMC/MGH

Phase 1 Interventional Massachusetts General Hospital · NCT04540380

This study is testing a new treatment approach to see if it can help kidney transplant patients avoid long-term medications by making their bodies accept the new kidney better.

Quick facts

PhasePhase 1
Study typeInterventional
Enrollment20 (estimated)
Ages18 Years to 65 Years
SexAll
SponsorMassachusetts General Hospital Academic / other
Drugs / interventionsSiplizumab, rituximab, radiation, Cyclophosphamide, Fludarabine
Locations1 site (Boston, Massachusetts)
Trial IDNCT04540380 on ClinicalTrials.gov

What this trial studies

This clinical trial aims to evaluate the safety of a conditioning regimen designed to induce donor/recipient lymphohematopoietic chimerism, which may lead to donor-specific unresponsiveness to renal allografts without the need for ongoing immunosuppression. The approach involves administering a combination of Rituximab, Fludarabine, Cyclophosphamide, Thymic irradiation, and Siplizumab, alongside a combined bone marrow and kidney transplant. The study focuses on patients with chronic kidney disease or end-stage renal disease who are candidates for a living-donor renal transplant from an HLA mismatched donor.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18-65 who are undergoing their first living-donor renal transplant from an HLA mismatched donor.

Not a fit: Patients with ABO blood group incompatibility or significant comorbidities such as active infections or severe heart failure may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could significantly reduce the need for lifelong immunosuppressive therapy in kidney transplant recipients.

How similar studies have performed: While the concept of mixed chimerism is promising, this specific approach is relatively novel and has not been extensively tested in prior studies.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Male or female 18-65 years of age.
* Candidate for a living-donor renal allograft from an HLA mismatched donor
* Subjects with chronic kidney disease stage or ESRD who are treated with either hemodialysis or peritoneal dialysis.
* First transplant.
* Use of FDA-approved methods of contraception
* Ability to understand and provide informed consent.
* Negative COVID at screening and 2 days before procedure

Exclusion Criteria:

* ABO blood group-incompatible renal allograft.
* Participant with a (non DSA) PRA \> 20% within 6 months prior to transplant
* Persistent Leukopenia (WBC less than 2,000/mm3) or thrombocytopenia (\<100,000/mm3).
* Seropositivity for HIV-1, hepatitis B core antigen, or hepatitis C virus (confirmed by hepatitis C virus RNA); or positivity for hepatitis B surface antigen.
* Active infection
* Left ventricular ejection fraction \< 40% as determined by TTE or clinical evidence of heart failure
* Forced expiratory volume FEV1 or DLCO \< 50% of predicted.
* Lactation or pregnancy
* History of cancer (following the American Transplant Society Guidelines)
* Underlying renal disease etiology with a high risk of disease recurrence in the transplanted kidney (such as focal segmental glomerulosclerosis).
* Prior dose-limiting radiation therapy
* Known genetic disease or family history that may result in greater sensitivity to the effects of irradiation, or a physical deformity that would preclude adequate shielding or appropriate dosing during the irradiation component of the conditioning regimen
* Enrollment in other investigational drug studies within 30 days prior to enrollment
* Abnormal (\>2 times lab normal) values for (a) liver function chemistries (ALT, AST, AP), (b) bilirubin, (c) coagulation studies (PT, PTT).
* Allergy or sensitivity to any component of Siplizumab, Fludarabine, Cyclophosphamide, tacrolimus, DMSO, MMF or rituximab.
* The presence of any medical condition that the investigator deems incompatible with participation in the trial.
* Subjects who have non-insulin dependent diabetes (NIDDM) without good blood glucose control (HbA1c\<7). Subject with severe retinopathy, gastroparesis, or severe neuropathy which prevent subject's normal independent daily activities will be excluded from the study

Where this trial is running

Boston, Massachusetts

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Renal Failure
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.