Desensitization With Tocilizumab and IVIg: A Prospective Controlled Cohort Study in a Predominantly Black American Population

BACKGROUND: Desensitization strategies for highly sensitized kidney transplant candidates remain limited in efficacy. Tocilizumab, an interleukin-6 receptor antagonist, has been proposed as an adjunct to IVIg to reduce HLA antibody burden. METHODS: In this prospective controlled cohort study, highly sensitized candidates (median calculated panel reactive antibody [cPRA], 98.0%) were (n = 19) or were not (n = 15) treated with tocilizumab and IVIg. All tocilizumab-treated patients had failed ≥3 mo of IVIg-based desensitization. We assessed changes in cPRA, unacceptable antigens (U/As), transplant rates, and posttransplant outcomes. RESULTS: Tocilizumab-treated patients were more likely to demonstrate any reduction in cPRA during the study period (84.2% versus 33.3%; P = 0.002). Median cPRA change at nadir was -0.9% versus 0.0% (P = 0.02), although end-of-study differences were not statistically significant. Treated patients more frequently achieved removal of high-impact U/As (median cPRA of removed U/As 31.7% versus 0.0%; P = 0.004), and 3 underwent transplantation across antigens previously listed as unacceptable. Transplant rates (89.5% versus 73.3%; P = 0.4) and early posttransplant outcomes-including rejection, graft loss, BK viremia, renal function, de novo donor-specific antibody, and donor-specific antibody rebound-were similar between groups. CONCLUSIONS: In this controlled cohort, tocilizumab combined with IVIg was associated with greater reductions in HLA antibody burden without an apparent increase in early posttransplant immunologic risk. These findings support further evaluation of interleukin-6 (IL-6) blockade as an adjunctive desensitization strategy, particularly in candidates with limited transplant access despite high allocation priority.