Tolerance Through Mixed Chimerism (Sip-Tego)

This is an open-label, single-institution study to assess the safety and the efficacy of the Sip-Tego regimen for the induction of donor-specific immunologic unresponsiveness to a renal allograft. The investigators propose to treat 6 adult subjects in end-stage renal disease (ESRD) who do not demonstrate evidence of prior sensitization.

The conditioning regimen to be used in this protocol consists of an ordered series of procedures and treatments including thymic irradiation, low-dose cyclophosphamide, antibody administration (Siplizumab, rituximab and tegoprubart), and bone marrow cell infusion. The surgical techniques for the renal transplant will be accomplished according to the surgeon's clinical judgment and experience using standard techniques in use at the institution. The donor nephrectomy will be accomplished according to the surgeon's clinical judgment and experience. The conditioning regimen requires six days leading up to the day of transplantation, which is designated as study Day 0. Negative numbers in descending order designate days pre-transplant, while positive numbers in ascending order designate days post-transplant. Refer to Figure 2 in Section 1.2. for the schema of the conditioning regimen.