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Kidney Week

Abstract: FR-OR115

MDR-101-MLK Update: Operational Immune Tolerance Achieved in Living Related HLA-Matched Kidney Transplant Recipients

Session Information

Category: Development, Stem Cells, and Regenerative Medicine

  • 600 Development, Stem Cells, and Regenerative Medicine

Authors

  • Kaufman, Dixon, University of Wisconsin System, Madison, Wisconsin, United States
  • Stegall, Mark D., Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Akkina, Sanjeev, Loyola University Medical Center, Maywood, Illinois, United States
  • Piper, James B., Inova, Falls Church, Virginia, United States
  • Asch, William S., Yale School of Medicine, New Haven, Connecticut, United States
  • Busque, Stephan, Stanford University School of Medicine, Stanford, California, United States
  • Gaber, Ahmed Osama, Houston Methodist Hospital, Houston, Texas, United States
  • Mai, Martin L., Mayo Clinic Florida, Jacksonville, Florida, United States
  • de Vera, Michael E., Loma Linda University Medical Center, Loma Linda, California, United States
  • Collette, Suzon, Hopital Maisonneuve-Rosemont, Montreal, Quebec, Canada
  • Patel, Anup M., Cooperman Barnabas Medical Center, Livingston, New Jersey, United States
  • Shah, Ashesh Piyush, Thomas Jefferson University, Philadelphia, Pennsylvania, United States
  • Stites, Erik, University of Colorado, Denver, Colorado, United States
  • Micsa, Lenuta, Medeor Therapeutics, South San Francisco, California, United States
  • Brennan, Daniel C., Medeor Therapeutics, South San Francisco, California, United States
Background

We describe the updated results from a Phase 3 RCT in recipients of HLA-matched living donor (LD) kidney transplants (KTxp) who received investigational cellular product, MDR-101, for induction of immune tolerance and elimination of immunosuppressive (IS) drugs vs standard of care (SOC) (NCT03363945).

Methods

Eligible adult, recipients (R) of a 1st kidney from an HLA-matched related LD were randomized 2:1 to Investigational Arm (IA; n=20) or Control Arm (CA; n=10). Peripheral blood CD34+ and CD3+ cells for MDR-101 were collected via apheresis from the same kidney donor. IA-Rs were transplanted day (D) 0 and received rATG (D0-4), total lymphoid irradiation (10 fractions), initiation of CNI, followed by an MDR-101 infusion (D11). Steroids were withdrawn by D10 and MMF was given D11-D39. CNI monotherapy continued till D180 and tapered to complete withdrawal 1-year post-transplant (tx) if donor hematopoietic mixed chimerism was ≥5%, and no rejection (BPAR), GvHD, or kidney loss. CA-Rs received IS per institutional SOC.

Results

20 IA-Rs received tolerance induction conditioning including MDR-101 infusion. 1 IA-R not an HLA-matched (a protocol deviation) and <6 mos of chimerism did not qualify for IS withdrawal. 19 IA-Rs successfully discontinued IS 1-year post-tx. To date, the number of IA-Rs and time remaining off IS: for 12 mos (n=17/19), 12-24 mos (n=17/19), 24 mos (n=12/14). 4 IA-Rs remain off IS and are yet to reach 24 mos off IS. 3 IA-Rs resumed IS: recurrent IgAN (18.7 mos off IS), recurrent IgAN and rejection (4.8 mos off IS), and rejection (11.2 mos off IS). No GvHD, PTLD or other malignancies occurred. No death occurred in either group. 1 IAR developed recurrent IgAN and after study completion had graft loss (4.3 years post-tx). D365 mean eGFR was 64.37 mL/min (IA-R) and 58.78 mL/min (CA-R). D730 mean eGFR was 62.37 mL/min (IA-R) and 62.22 mL/min (CA-R).

Conclusion

MDR-101 can safely achieve donor mixed chimerism and operational immune tolerance with complete elimination of all IS with no death, graft loss, or GvHD in HLA-matched LD recipients. The protocol anticipated treatment success of at least 48% IA-R IS-Free for at least 24 mos was met.