Paul Brailey

Bortezomib provides effective therapy for antibody- and cell-mediated acute rejection.

Background. Current antihumoral therapies in transplantation and autoimmune disease do not target the mature antibody-producing plasma cell. Bortezomib is a first in class proteosomal inhibitor, that is Food and Drug Administration approved, for the treatment of plasma cell-derived tumors that is multiple myeloma. We report the first clinical experience with plasma cell-targeted therapy (bortezomib) as an antirejection strategy. Methods. Eight episodes of mixed antibody-mediated rejection (AMR) and acute cellular rejection (ACR) in six transplant recipients were treated with bortezomib at labeled dosing. Monitoring included serial donor-specific antihuman leukocyte antigen antibody (DSA) levels and repeated allograft biopsies. Results. Six kidney transplant patients received bortezomib for AMR and concomitant ACR. In each case, bortezomib therapy provided (1) prompt rejection reversal, (2) marked and prolonged reductions in DSA levels, (3) improved renal allograft function, and (4) suppression of recurrent rejection for at least 5 months. Moreover, immunodominant DSA (iDSA) (i.e., the antidonor human leukocyte antigen antibody with the highest levels) levels were decreased by more than 50% within 14 days and remained substantially suppressed for up to 5 months. One or more additional DSA were present at lower concentrations (non-iDSA) in each patient and were also reduced to nondetectable levels. Bortezomib-related toxicities (gastrointestinal toxicity, thrombocytopenia, and paresthesias) were all transient. Conclusions. Bortezomib therapy: (1) provides effective treatment of AMR and ACR with minimal toxicity and (2) provides sustained reduction in iDSA and non-iDSA levels. Bortezomib represents the first effective antihumoral therapy with activity in humans that targets plasma cells.

Reducing De Novo Donor‐Specific Antibody Levels during Acute Rejection Diminishes Renal Allograft Loss

The effect of de novo DSA detected at the time of acute cellular rejection (ACR) and the response of DSA levels to rejection therapy on renal allograft survival were analyzed. Kidney transplant patients with acute rejection underwent DSA testing at rejection diagnosis with DSA levels quantified using Luminex single‐antigen beads. Fifty‐two patients experienced acute rejection with 16 (31%) testing positive for de novo DSA. Median follow‐up was 27.0 ± 17.4 months postacute rejection. Univariate analysis of factors influencing allograft survival demonstrated significance for African American race, DGF, cytotoxic PRA >20% (current) and/or >50% (peak), de novo DSA, C4d and repeat transplantation. Multivariate analysis showed only de novo DSA (6.6‐fold increased allograft loss risk, p = 0.017) to be significant. Four‐year allograft survival was higher with ACR (without DSA) (100%) than mixed acute rejection (ACR with DSA/C4d) (65%) or antibody‐mediated rejection (35%) (p < 0.001). Patients with >50% reduction in DSA within 14 days experienced higher allograft survival (p = 0.039). De novo DSAs detected at rejection are associated with reduced allograft survival, but prompt DSA reduction was associated with improved allograft survival. DSA should be considered a potential new end point for rejection therapy.

Proteasome Inhibitor-Based Primary Therapy for Antibody-Mediated Renal Allograft Rejection

Background. Rapid and complete elimination of donor-specific anti-human leukocyte antigen antibodies (DSA) during antibody-mediated rejection (AMR) is rarely achieved with traditional antihumoral therapies. Proteasome inhibitor-based therapy has been shown to effectively treat refractory AMR, but its use as a primary therapy for AMR has not been presented. Our initial experience with proteasome inhibition as a first-line therapy for AMR is presented. Methods. Adult kidney transplant recipients with AMR, diagnosed by Banff criteria, received a bortezomib-based regimen as the primary therapy. Bortezomib therapy was administered per package insert with plasmapheresis performed immediately before each bortezomib dose, and a single rituximab dose (375 mg/m2) given with the first bortezomib dose. DSA were quantitated using single-antigen beads on a Luminex platform. Results. Two patients underwent bortezomib-based therapy for acute AMR occurring within the first 2 weeks after transplantation. High DSA levels and positive C4d staining of peritubular or glomerular capillaries were present at the time of diagnosis. Both patients experienced prompt AMR reversal and elimination of detectable DSA within 14 days of bortezomib-based therapy. Renal function remains excellent with normal urinary protein excretion at 5 and 6 months after AMR diagnosis. One patient experienced a repeated elevation of DSA (including two new human leukocyte antigen specificities) 2 months after initial bortezomib therapy, but without C4d deposition or histologic evidence of AMR. Retreatment with bortezomib provided prompt, complete, and durable DSA elimination. Conclusions. Proteasome inhibitor-based combination therapy provides a potential means for rapid DSA elimination in early acute AMR in renal transplant recipients.

Early and Late Acute Antibody-Mediated Rejection Differ Immunologically and in Response to Proteasome Inhibition

Background. The efficacy of plasma cell targeted therapies for antibody-mediated rejection (AMR) has not been defined in detail. The purpose of this study was to compare early and late acute AMR in terms of immunologic characteristics and responses with proteasome inhibitor (PI) therapy. Methods. Renal transplant recipients with acute AMR were treated with PI-based regimens. Early acute AMR was defined as occurring within 6 months posttransplant. Immunodominant donor-specific antibody (iDSA) was defined as the DSA with the highest level. Results. Results are expressed as early or late acute AMR. Thirty AMR episodes (13 early, 17 late) were treated in 12 and 16 patients. Early but not late AMR was associated with presensitization. Late AMR iDSA levels were higher, and specificities were primarily class II (DQ being most frequent). Early AMR patients demonstrated greater reduction in iDSA at 7, 14, and 30 days and at the posttreatment nadir (81.5%+21.2% vs. 51.4%+27.6%; P<0.01). Early AMR patients were more likely to demonstrate histologic resolution/improvement (87.5% vs. 53.8%; P=0.13). Both groups demonstrated significant improvement in renal function. Conclusions. Early and late AMR exhibit distinct immunologic characteristics and respond differently to PI therapy.

Prospective Iterative Trial of Proteasome Inhibitor-Based Desensitization

A prospective iterative trial of proteasome inhibitor (PI)‐based therapy for reducing HLA antibody (Ab) levels was conducted in five phases differing in bortezomib dosing density and plasmapheresis timing. Phases included 1 or 2 bortezomib cycles (1.3 mg/m2 × 6–8 doses), one rituximab dose and plasmapheresis. HLA Abs were measured by solid phase and flow cytometry (FCM) assays. Immunodominant Ab (iAb) was defined as highest HLA Ab level. Forty‐four patients received 52 desensitization courses (7 patients enrolled in multiple phases): Phase 1 (n = 20), Phase 2 (n = 12), Phase 3 (n = 10), Phase 4 (n = 5), Phase 5 (n = 5). iAb reductions were observed in 38 of 44 (86%) patients and persisted up to 10 months. In Phase 1, a 51.5% iAb reduction was observed at 28 days with bortezomib alone. iAb reductions increased with higher bortezomib dosing densities and included class I, II, and public antigens (HLA DRβ3, HLA DRβ4 and HLA DRβ5). FCM median channel shifts decreased in 11/11 (100%) patients by a mean of 103 ± 54 mean channel shifts (log scale). Nineteen out of 44 patients (43.2%) were transplanted with low acute rejection rates (18.8%) and de novo DSA formation (12.5%). In conclusion, PI‐based desensitization consistently and durably reduces HLA Ab levels providing an alternative to intravenous immune globulin‐based desensitization.

Successful Simultaneous Liver-Kidney Transplantation in the Presence of Multiple High-Titered Class I and II Antidonor HLA Antibodies.

Abstract The results of simultaneous liver-kidney transplants in highly sensitized recipients have been controversial in terms of antibody-mediated rejection and kidney allograft outcomes. This case report provides a detailed and sophisticated documentation of histocompatibility and pathologic data in a simultaneous liver-kidney transplant performed in a recipient with multiple high-titered class I and II antidonor HLA antibodies and a strongly positive cytotoxic crossmatch. Patient received induction with steroids, rituximab, and eculizumab without lymphocyte depleting agents. The kidney transplant was delayed by 6 hours after the liver transplant to allow more time to the liver allograft to “absorb” donor-specific antibodies (DSA). Interestingly, the liver allograft did not prevent immediate antibody-mediated injury to the kidney allograft in this highly sensitized recipient. Anti-HLA single antigen bead analysis of liver and kidney allograft biopsy eluates revealed deposition of both class I and II DSA in both liver and kidney transplants during the first 2 weeks after transplant. Afterward, both liver and kidney allograft functions improved and remained normal after a year with progressive reduction in serum DSA values.

A Phase Ib, Open Label, Single Arm Study to Assess the Safety, Pharmacokinetics, and Impact on Humoral Sensitization of SANGUINATE Infusion in Patients with End-Stage Renal Disease

The endeavor to study desensitization in kidney transplantation has not been matched by an effort to investigate strategies to prevent sensitization. In this study (NCT02437422), we investigated the safety, impact on sensitization, and pharmacokinetics of SANGUINATE (SG), a hemoglobin‐based oxygen carrier, as a potential alternative to packed red blood cells (PRBC) in transplant candidates with end‐stage renal disease (ESRD). Ten ESRD subjects meeting inclusion/exclusion (I/E) criteria were planned to receive three weekly infusions of SG (320 mg/kg). The study was stopped after five subjects were enrolled, and their data were analyzed after completing a follow‐up period of 90 days. Two subjects had elevated troponin I levels in setting of SG infusion, one of which was interpreted as a non‐ST elevation myocardial infarction. All other adverse events were transient. SG pharmacokinetic analysis showed mean (SD) Cmax, Tmax, AUC, and half‐life of 4.39 (0.69) mg/mL, 2.42 (0.91) hours, 171.86 (52.35) mg h/mL, and 40.60 (11.96) hours, respectively. None of the subjects developed new anti‐HLA antibodies following SG infusion and throughout the study period. In conclusion, SG is a potential alternative to PRBCs in ESRD patients considered for kidney transplantation as it was not associated with humoral sensitization. Larger studies in highly sensitized patients are required to further evaluate for potential safety signals.

MULTIVARIATE ANALYSES OF ACUTE REJECTION IN RENAL TRANSPLANT RECIPIENTS RECEIVING EARLY CORTICOSTEROID WITHDRAWAL: 104

A.R. Shields1, R.R. Alloway2, G. Mogilishetty2, M. Cardi3, S. Huang3, L. Arend4, P. Brailey5, R. Munda6, J. Everly7, E.S. Woodle6 1Transplant Surgery, University of Cincinnati, Cincinnati/Ohio/UNITED STATES OF AMERICA, 2Nephrology, University of Cincinnati, cincinnati/UNITED STATES OF AMERICA, 3Nephrology, The Christ Hospital, cincinnati/UNITED STATES OF AMERICA, 4Pathology, University of Cincinnati, cincinnati/UNITED STATES OF AMERICA, 5Hoxworth Immunology, University of Cincinnati, cincinnati/UNITED STATES OF AMERICA, 6Transplant Surgery, University of Cincinnati, cincinnati/UNITED STATES OF AMERICA, 7, Oncology Hematology, Inc, cincinnati/UNITED STATES OF AMERICA