Imlifidase in Highly Sensitized Kidney Transplant Recipients With a Positive Crossmatch Against a Deceased Donor

Abstract

IntroductionImlifidase is authorized for desensitization of highly sensitized adult kidney transplant candidates with a positive crossmatch against a deceased donor. Here, we report on the results for the first 9 patients transplanted in this context who had at least 3 months of follow-up. MethodsThe eligibility criteria were: calculated panel reactive antibodies (cPRA) ≥ 98%, ≥ 3 years on the waiting list, immunodominant donor specific antibodies (iDSA) with mean fluorescence intensity (MFI) > 6,000 (and < 5,000 at 1:10 dilution) and a negative post-imlifidase complement-dependent cytotoxic crossmatch (CDCXM). ResultsAll 9 patients had been on dialysis for an average of 123±41 months, with cPRA at 99% (n=2) or 100% (n=7). At transplantation, the mean number of DSA was 4.3±1.4. The median iDSA MFI was 9,153 (6,430-16,980). Flow cytometry and CDC XMs before imlifidase were positive in 9 and 2 patients, respectively. After one injection of imlifidase all were negative. Patients received polyclonal antibodies, intravenous immunoglobulins, rituximab, tacrolimus, and mycophenolate. Five patients had a DSA rebound within the first 14 days: 2 had concomitant clinical antibody-mediated rejection (ABMR), 2 had subclinical ABMR, and 1 had isolated positive C4d staining. No ABMR was observed in patients without rebound. CKD-EPI eGFR was 56±22 mL/min/1.73m2 at the last follow-up (7±2.8 months). No graft loss or death were observed. Four patients developed at least one infection. ConclusionThese real-life data demonstrate that the use of imlifidase to desensitize highly sensitized patients can have an acceptable short-term efficacy and safety profile in selected patients.