Evolution of donor-specific antibodies (DSA) and incidence ofde novoDSA in solid organ transplant recipients after switch to everolimus alone or associated with low dose of calcineurin inhibitors

Everolimus Based Immunosuppression Strategies in Adult Lung Transplant Recipients: Calcineurin Inhibitor Minimization Versus Calcineurin Inhibitor Elimination

Everolimus (EVE) provides an alternative to maintenance immunosuppression when conventional immunosuppression cannot be tolerated. EVE can be utilized with a calcineurin inhibitor (CNI) minimization or elimination strategy. To date, clinical studies investigating EVE after lung transplant (LTx) have primarily focused on the minimization strategy to preserve renal function. The primary aim was to determine the preferred method of EVE utilization for lung transplant recipients (LTR). To undertake this aim, we compared the safety and efficacy outcomes of EVE as part of minimization and elimination immunosuppressant regimens. Single center retrospective study of 217 LTR initiated on EVE (120 CNI minimization and 97 CNI elimination). Survival outcomes were calculated from the date of EVE commencement. On multivariate analysis, LTR who received EVE as part of the CNI elimination strategy had poorer survival outcomes compared to the CNI minimization strategy [HR 1.61, 95% CI: 1.11-2.32, p=0.010]. Utilization of EVE for renal preservation was associated with improved survival compared to other indications [HR 0.64, 95% CI: 0.42-0.97, p=0.032]. EVE can be successfully utilized for maintenance immunosuppression post LTx, particularly for renal preservation. However, immunosuppressive regimens containing low dose CNI had superior survival outcomes, highlighting the importance of retaining a CNI wherever possible.

An overview of the efficacy and safety of everolimus in adult solid organ transplant recipients

As the risk of graft loss due to acute rejection has declined, the goal of post-transplant management has switched to long-term preservation of organ function. Minimizing calcineurin inhibitor (CNI)-related nephrotoxicity is a key component of this objective. Everolimus is a mammalian target of rapamycin inhibitor/proliferation-signal inhibitor with potent immunosuppressive and anti-proliferative effects. It has been widely investigated in large randomized clinical studies that have shown it to have similar anti-rejection efficacy compared with standard-of-care regimens across organ transplant indications. With demonstrated potential to facilitate the reduction of CNI therapy and preserve renal function, everolimus is an alternative to the current standard-of-care CNI-based regimens used in de novo and maintenance solid organ transplantation recipients. Here, we provide an overview of the evidence from the everolimus clinical study program across kidney, liver, heart, and lung transplants, as well as other key data associated with its use in CNI reduction strategies in adult transplant recipients.

Everolimus-facilitated calcineurin inhibitor reduction in Asian de novo kidney transplant recipients: Two-year results from the subgroup analysis of the TRANSFORM study

Objective

We analyzed the efficacy and safety of an everolimus with reduced‐exposure calcineurin inhibitor (EVR+rCNI) versus mycophenolic acid with standard‐exposure CNI (MPA+sCNI) regimen in Asian patients from the TRANSFORM study.

Methods

In this 24‐month, open‐label study, de novo kidney transplant recipients (KTxRs) were randomized (1:1) to receive EVR+rCNI or MPA+sCNI, along with induction therapy and corticosteroids.

Results

Of the 2037 patients randomized in the TRANSFORM study, 293 were Asian (EVR+rCNI, N = 136; MPA+sCNI, N = 157). At month 24, EVR+rCNI was noninferior to MPA+sCNI for the binary endpoint of estimated glomerular filtration rate (eGFR) < 50 ml/min/1.73 m² or treated biopsy‐proven acute rejection (27.0% vs. 29.2%, P = .011 for a noninferiority margin of 10%). Graft loss and death were reported for one patient each in both arms. Mean eGFR was higher in EVR+rCNI versus MPA+sCNI (72.2 vs. 66.3 ml/min/1.73 m², P = .0414) even after adjusting for donor type and donor age (64.3 vs. 59.3 ml/min/1.73 m², P = .0582). Overall incidence of adverse events was comparable. BK virus (4.4% vs. 12.1%) and cytomegalovirus (4.4% vs. 13.4%) infections were significantly lower in the EVR+rCNI arm.

Conclusion

This subgroup analysis in Asian de novo KTxRs demonstrated that the EVR+rCNI versus MPA+sCNI regimen provides comparable antirejection efficacy, better renal function, and reduced viral infections (NCT01950819).

Donor-Specific Antibodies Against Donor Human Leukocyte Antigen are Associated with Graft Inflammation but Not with Fibrosis Long-Term After Liver Transplantation: An Analysis of Protocol Biopsies

Background

Donor-specific antibodies (DSA) against donor human leukocyte antigen after liver transplantation, which are associated with histological changes, have been widely studied with respect to their sustained impact on transplant function. However, their long-term impact after liver transplantation remains unclear.

Methods

We performed a cross-sectional analysis from June 2016 to July 2017 that included all patients who presented themselves for scheduled follow-up after receiving a liver transplantation between September 1989 and December 2016. In addition to a liver protocol biopsy, patients were screened for human leukocyte antigen antibodies (HLAab) and donor-specific antibodies. Subsequently, the association between human leukocyte antigen antibodies, donor-specific antibodies, histologic and clinical features, and immunosuppression was analyzed.

Results

Analysis for human leukocyte antigen antibodies and donor-specific antibodies against donor human leukocyte antigen was performed for 291 and 271 patients. A significant association between higher inflammation grades and the presence of human leukocyte antigen antibodies and donor-specific antibodies was detected, while fibrosis stages remained unaffected. These results were confirmed by multivariate logistic regression for inflammation showing a significant increase for presence of human leukocyte antigen antibodies and donor-specific antibodies (OR: 4.43; 95% CI: 1.67–12.6; p=0.0035). Furthermore, the use of everolimus in combination with tacrolimus was significantly associated with the status of negative human leukocyte antigen antibodies and donor-specific antibodies. Viral etiology for liver disease, hepatocellular carcinoma (HCC) and higher steatosis grades of the graft were significantly associated with a lower rate of human leukocyte antigen antibodies. The impact of human leukocyte antigen antibodies and donor-specific antibodies against donor human leukocyte antigen was associated with higher levels of laboratory parameters, such as transaminases and bilirubin.

Conclusion

Donor-specific antibodies against donor human leukocyte antigen are associated with histological and biochemical graft inflammation after liver transplantation, while fibrosis seems to be unaffected. Future studies should validate these findings for longer observation periods and specific subgroups.

Long-term Efficacy and Safety of Everolimus Versus Mycophenolate in Kidney Transplant Recipients Receiving Tacrolimus

BACKGROUND

The short-term efficacy and safety of everolimus in combination with tacrolimus have been described in several clinical trials. Yet, detailed long-term data comparing the use of everolimus or mycophenolate in kidney transplant recipients receiving tacrolimus is lacking.

METHODS

This is a 5-year follow-up post hoc analysis of a prospective trial including 288 patients who were randomized to receive a single 3 mg/kg dose of rabbit antithymocyte globulin, tacrolimus, everolimus, and prednisone (r-ATG/EVR, n=85); basiliximab, tacrolimus, everolimus, and prednisone (BAS/EVR, n=102); or basiliximab, tacrolimus, mycophenolate, and prednisone (BAS/MPS, n=101).

RESULTS

There were no differences in the incidence of treatment failure (31.8% vs. 40.2% vs. 34.7%, p=0.468), de novo donor-specific HLA antibodies (6.5 vs. 11.7 vs. 4.0%, p=0.185), patient (92.9% vs. 94.1% vs. 92.1%, p = 0.854) and death-censored graft (87.1% vs. 90.2% vs. 85.1%, p = 0.498) survivals. Using a sensitive analysis, the trajectories of eGFR were comparable in the intention-to-treat (p=0.145) and per protocol (p=0.354) populations. There were no differences in study drug discontinuation rate (22.4% vs. 30.4% vs. 17.8%, p=0.103).

CONCLUSIONS

In summary, this analysis in a cohort of de novo low/moderate immunologic risk kidney transplant recipients suggests that the use of a single 3mg/kg r-ATG dose followed by EVR combined with reduced TAC concentrations was associated with similar efficacy and renal function compared to the standard of care immunosuppressive regimen.Supplemental Visual Abstract; http://links.lww.com/TP/C160.

Everolimus for BKV nephropathy in kidney transplant recipients: a prospective, controlled study

There is no specific therapy for polyoma BK virus nephropathy (BKVN) in kidney transplant recipients, a condition associated with poor outcomes. Everolimus showed promising antiviral effects, but data from prospective studies are limited. Therefore, we converted ten consecutive kidney transplant recipients with biopsy-proven BKVN from standard exposure Calcineurin inhibitors and Mycophenolate to Everolimus and reduced exposure Calcineurin inhibitors. Ten patients not administered Everolimus, on reduced exposure Calcineurin inhibitor and halved MPA doses served as controls. All kidney transplant recipients continued steroid therapy. Each patient underwent kidney graft biopsy, BKV replication by PCR, and de novo DSA determination. During a 3-year follow-up no graft loss occurred in kidney transplant recipients on Everolimus but it was observed in 5/10 controls (P = 0.032). eGFR improved on Everolimus and worsened in controls (between group difference + 25.6 ml/min/1.73 m², 95% CI 10.5-40.7, P = 0.002). BKV replication declined in the Everolimus group alone (from 6.4 ± 0.8 to 3.6 ± 1.6 Log 10 genomic copies, P = 0.0001), and we found a significant inverse relationship between eGFR and BKV genomic copy changes (P = 0.022). Average Calcineurin inhibitors trough levels did not differ between the two study groups during follow-up. By multivariable Cox regression analysis, Everolimus treatment resulted the only significant predictor of survival free of a combined endpoint of graft loss and 57% eGFR reduction (P = 0.02). Kidney transplant recipients on Everolimus had a higher survival free of adverse graft outcome (log-rank test, P = 0.009). In conclusion an Everolimus-based immunosuppressive protocol with minimization of Calcineurin inhibitors and antimetabolite discontinuation effectively treated BKVN in kidney transplant recipients.

Two-year outcomes in de novo renal transplant recipients receiving everolimus-facilitated calcineurin inhibitor reduction regimen from the TRANSFORM study

TRANSFORM (TRANSplant eFficacy and safety Outcomes with an eveRolimus-based regiMen) was a 24-month, prospective, open-label trial in 2037 de novo renal transplant recipients randomized (1:1) within 24 hours of transplantation to receive everolimus (EVR) with reduced-exposure calcineurin inhibitor (EVR + rCNI) or mycophenolate with standard-exposure CNI. Consistent with previously reported 12-month findings, noninferiority of the EVR + rCNI regimen for the primary endpoint of treated biopsy-proven acute rejection (tBPAR) or estimated glomerular filtration rate (eGFR) <50 mL/min per 1.73 m² was achieved at month 24 (47.9% vs 43.7%; difference = 4.2%; 95% confidence interval = -0.3, 8.7; P = .006). Mean eGFR was stable up to month 24 (52.6 vs 54.9 mL/min per 1.73 m² ) in both arms. The incidence of de novo donor-specific antibodies (dnDSA) was lower in the EVR + rCNI arm (12.3% vs 17.6%) among on-treatment patients. Although discontinuation rates due to adverse events were higher with EVR + rCNI (27.2% vs 15.0%), rates of cytomegalovirus (2.8% vs 13.5%) and BK virus (5.8% vs 10.3%) infections were lower. Cytomegalovirus infection rates were significantly lower with EVR + rCNI even in the D+/R- high-risk group (P < .0001). In conclusion, the EVR + rCNI regimen offers comparable efficacy and graft function with low tBPAR and dnDSA rates and significantly lower incidence of viral infections relative to standard-of-care up to 24 months. Clinicaltrials.gov number: NCT01950819.

mTOR inhibitors and risk of chronic antibody-mediated rejection after kidney transplantation: where are we now?

Antibody-mediated rejection (AMR) usually starts with generation of donor-specific anti-HLA antibodies (DSAs), arising from a B-cell response to antigen recognition. In vitro and preclinical data demonstrate that mammalian target of rapamycin (mTOR) inhibition attenuates the mTOR-mediated intracellular signaling pathway involved in AMR-related kidney damage. The limited available data from immunological studies in kidney transplant patients, however, have not shown such effects in vivo. In terms of clinical immunosuppression, the overriding influence on rates of de novo DSA (dnDSA) or AMR-regardless of the type of regimen-is patient adherence. To date, limited data from patients given mTOR inhibitor therapy with adequate concurrent immunosuppression, such as reduced-exposure calcineurin inhibitor (CNI) therapy, have not shown an adverse effect on the risk of dnDSA or AMR. Early switch to an mTOR inhibitor (<6-12 months post-transplant) in a CNI-free regimen, in contrast, can increase the risk of dnDSA, especially if adjunctive therapy is inadequate. Late conversion to CNI-free therapy with mTOR inhibition does not appear to affect the risk of dnDSA. More data, from prospective studies, are required to fully understand that association between use of mTOR inhibitors with different types of concomitant therapy and risk of dnDSA and AMR.

Impact of Antibodies That React With Liver Tissue and Donor-Specific Anti-HLA Antibodies in Pediatric Idiopathic Posttransplantation Hepatitis

Background

The cause of late graft dysfunction has not been elucidated. Although an antibody-mediated reaction is suspected as a potential mechanism, the target antigens have not been clarified.

Methods

To clarify the etiology of idiopathic posttransplantation hepatitis (IPTH), we simultaneously examined the presence of antibodies that react with liver tissue (ARLT) by means of indirect immunofluorescence staining, as well as the presence of donor-specific anti-human leukocyte antigen antibodies (HLA-DSA). A subanalysis of the IPTH group was also performed. Within the IPTH group, the correlation between ARLT titer and clinical data were analyzed.

Results

In the sera of patients with IPTH (30 patients), ARLT were found at a significantly higher frequency than in patients without IPTH (42 patients; P < 0.001). Moreover, the ARLT titer appeared to be correlated with the severity of hepatitis or hepatic injury. In contrast, the frequency of HLA-DSA was significantly lower in patients with IPTH than in patients without IPTH (P = 0.001).

Conclusion

Our findings indicate that ARLT, and not HLA-DSA, profoundly influence the etiology of IPTH.

The authors show that antibodies that react with liver tissue and not donor-specific anti-human leukocyte antigen antibodies, profoundly influence the etiology of idiopathic posttransplantation hepatitis in children providing a rationale for therapy.

Early Conversion From Calcineurin Inhibitor- to Everolimus-Based Therapy Following Kidney Transplantation: Results of the Randomized ELEVATE Trial

In a 24-month, multicenter, open-label, randomized trial, 715 de novo kidney transplant recipients were randomized at 10-14 weeks to convert to everolimus (n = 359) or remain on standard calcineurin inhibitor (CNI) therapy (n = 356; 231 tacrolimus; 125 cyclosporine), all with mycophenolic acid and steroids. The primary endpoint, change in estimated glomerular filtration rate (eGFR) from randomization to month 12, was similar for everolimus versus CNI: mean (standard error) 0.3(1.5) mL/min/1.73² versus -1.5(1.5) mL/min/1.73² (p = 0.116). Biopsy-proven acute rejection (BPAR) at month 12 was more frequent under everolimus versus CNI overall (9.7% vs. 4.8%, p = 0.014) and versus tacrolimus-treated patients (2.6%, p < 0.001) but similar to cyclosporine-treated patients (8.8%, p = 0.755). Reporting on de novo donor-specific antibodies (DSA) was limited but suggested more frequent anti-HLA Class I DSA under everolimus. Change in left ventricular mass index was similar. Discontinuation due to adverse events was more frequent with everolimus (23.6%) versus CNI (8.4%). In conclusion, conversion to everolimus at 10-14 weeks posttransplant was associated with renal function similar to that with standard therapy overall. Rates of BPAR were low in all groups, but lower with tacrolimus than everolimus.

IgM-Enriched Human Intravenous Immunoglobulin-Based Treatment of Patients With Early Donor Specific Anti-HLA Antibodies After Lung Transplantation

BACKGROUND

At our institution, until April 2013, patients who showed early donor specific anti-HLA antibodies (DSA) after lung transplantation were preemptively treated with therapeutic plasma exchange (tPE) and a single dose of Rituximab. In April 2013, we moved to a therapy based on IgM-enriched human immunoglobulins (IVIG), repeated every 4 weeks, and a single dose of Rituximab.

METHODS

This observational study was designed to evaluate the short-term patient and graft survival in patients who underwent IVIG-based DSA treatment (group A, n = 57) versus contemporary patients transplanted between April 2013 and January 2015 without DSA (group C, n = 180), as well as to evaluate DSA clearance in IVIG-treated patients versus historic patients who had undergone tPE-based treatment (group B, n = 56). Patient records were retrospectively reviewed. Follow-up ended on April 1, 2015.

RESULTS

At 6 months and 1 year of follow-up, group A had a survival similar to group C (P = 0.81) but better than group B (P = 0.008). Group A showed statistically nonsignificant trends toward improved freedom from pulsed-steroid therapy and biopsy-confirmed rejection over groups B and C. The DSA clearance was better in group A than group B at treatment end (92% vs 64%; P = 0.002) and last DSA control (90% vs 75%; P = 0.04).

CONCLUSIONS

Patients with new early DSA but without graft dysfunction that are treated with IVIG and Rituximab have similarly good early survival as contemporary lung transplant recipients without early DSA. The IVIG yielded increased DSA clearance compared with historic tPE-based treatment, yet spontaneous clearance of new DSA also remains common.

Impact of Donor-Specific Antibodies on Graft Fibrosis After Pediatric Living Donor Liver Transplantation for Biliary Atresia

BACKGROUND

Pediatric living donor liver transplant (LDLT) patients sometimes develop graft fibrosis after non-recurrent diseases such as biliary atresia (BA). Donor-specific antibodies (DSA) have recently been shown to play a possible role in graft damage after liver transplantation. We report the impact of DSA on pediatric LDLT for BA patients.

METHODS

Patients under age 18 years who received LDLT for BA at our institution and who had at least 5 years' follow-up were identified, and 23 were eventually enrolled in this study. Pathological findings were assessed with the use of the last available biopsy. Patients were divided into 2 groups, DSA-positive and DSA-negative. Graft fibrosis after LDLT was assessed according to DSA groups.

RESULTS

The mean patient age at transplant was 2.6 years. The mean time to the last available biopsy after LDLT was 8.2 years (4.8-15.6 years); 6 patients (26%) showed no fibrosis, whereas fibrosis was graded as F1, F2, or F3 in 8 patients (35%), 8 patients (35%), and 1 patient, respectively. DSA were observed in 12 patients (52%). Moderate graft fibrosis (F2 and F3) was found in 7 (58%) of the DSA-positive group, but only 2 (18%) of the DSA-negative group, showing a statistically significant difference (P < .05). Pre-transplant cross-matching was performed in 17 patients. The 2 patients with a positive cross-match were DSA-positive. Six cross-match-negative patients developed de novo DSA after LDLT.

CONCLUSIONS

Graft fibrosis was observed after LDLT for BA during long-term follow-up, more commonly in DSA-positive patients. DSA may play a role in fibrosis formation.

The Influence of Immunosuppressive Agents on the Risk of De Novo Donor-Specific HLA Antibody Production in Solid Organ Transplant Recipients

Production of de novo donor-specific antibodies (dnDSA) is a major risk factor for acute and chronic antibody-mediated rejection and graft loss after all solid organ transplantation. In this article, we review the data available on the risk of individual immunosuppressive agents and their ability to prevent dnDSA production. Induction therapy with rabbit antithymocyte globulin may achieve a short-term decrease in dnDSA production in moderately sensitized patients. Rituximab induction may be beneficial in sensitized patients, and in abrogating rebound antibody response in patients undergoing desensitization or treatment for antibody-mediated rejection. Use of bortezomib for induction therapy in at-risk patients is of interest, but the benefits are unproven. In maintenance regimens, nonadherent and previously sensitized patients are not suitable for aggressive weaning protocols, particularly early calcineurin inhibitor withdrawal without lymphocyte-depleting induction. Early conversion to mammalian target of rapamycin inhibitor monotherapy has been reported to increase the risk of dnDSA formation, but a combination of mammalian target of rapamycin inhibitor and reduced-exposure calcineurin inhibitor does not appear to alter the risk. Early steroid therapy withdrawal in standard-risk patients after induction has no known dnDSA penalty. The available data do not demonstrate a consistent effect of mycophenolic acid on dnDSA production. Risk minimization for dnDSA requires monitoring of adherence, appropriate risk stratification, risk-based immunosuppression intensity, and prospective DSA surveillance.

Pilot conversion trial from mycophenolic acid to everolimus in ABO-incompatible kidney-transplant recipients with BK viruria and/or viremia

Immunosuppression using everolimus (EVR) plus low-dose tacrolimus (Tac) is commonly used in organ transplantation. EVR has potential antiviral effects. Herein, the long-term outcomes and impacts of Tac-EVR on the BK virus are reported in ABO-incompatible kidney-transplant recipients. The initial immunosuppressive regimen combined steroids, Tac, and mycophenolic acid (MPA). At a median of 141 (34-529) days post-transplantation, seven stable ABO-incompatible kidney-transplant recipients were converted from MPA to EVR because of active BK replication, and compared with a reference group of fourteen ABO-incompatible patients receiving classical Tac plus MPA. At 1 month before conversion, at 1, 3 months after, and at last follow-up, clinical and biological parameters were monitored. The median time from conversion to the last follow-up was 784 (398-866) days. Conversion to EVR caused no change to rejection episodes or immunological status (isoagglutinin titers, anti-HLA antibodies). At last follow-up, median eGFR was similar in the Tac-MPA versus Tac-EVR group (40 [range: 14-56] vs. 54.5 ml/min/1.73 m(2) [range: 0-128], P = 0.07). The major adverse event was dyslipidemia. Interestingly, conversion from MPA to EVR decreased BK viral load in five patients. ABO-incompatible kidney-transplant recipients with an active BK virus infection may benefit from conversion to EVR.