Immune Tolerance With MDR-101 in Transplant Recipients

By Charlotte Robinson - Last Updated: June 21, 2024

D.B. Kaufman, MD, PhD, FACS, and others studied recipients of human leukocyte antigen (HLA)-matched living donor (LD) kidney transplants who received an investigational cellular product (MDR-101) to produce immune tolerance, allowing stoppage of immunosuppression (IS) for 2 years compared with standard of care. They reported results at the American Transplant Congress 2024.

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Participants comprised adult recipients of a first kidney from an HLA-matched related LD who were randomized 2:1 to a treatment arm (TA, n=20) or control arm (CA, n=10). Patients in the CA arm received IS per standard of care. Patients in the TA arm were transplanted at day (D) 0 and received (rabbit) antithymocyte globulin D0-4 and low-dose total lymphoid irradiation to induce chimerism after MDR-101 infusion on D11. IS was given throughout 1 year and then discontinued. Steroids were withdrawn by D10, and mycophenolate mofetil was given D11-D39. Tacrolimus began on D11, and monotherapy continued from D40 until D180 and then gradually was withdrawn 1 year after transplant if mixed chimerism was ≥5% and there was no biopsy-proven acute rejection, graft-versus-host disease (GVHD), or kidney loss.

Nineteen (95%) TA patients discontinued all IS 1 year post-transplant; 16 (84%) were IS-free after 2 years; three resumed IS after temporary withdrawal. There was no graft loss, death, GVHD, post-transplant lymphoproliferative disorder, or other cancers. There was no significant difference in estimated glomerular filtration rate between groups.

In conclusion, the authors wrote, “MDR-101 safely achieved donor mixed chimerism and functional immune tolerance with complete elimination of all IS with no death, graft loss, or GVHD in HLA-matched LD kidney transplant recipients with improved quality of life.”

Source: Kaufman DB, Stegall M, Akkina S, et al. MDR-101-MLK-operational immune tolerance achieved in living related HLA-matched kidney transplant recipients. Abstract #627. Presented at the American Transplant Congress 2024; June 1-5, 2024; Philadelphia, Pennsylvania.

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