Predictive Modeling of Tacrolimus Dose Requirement Based on High-Throughput Genetic Screening.

Any biochemical reaction underlying drug metabolism depends on individual gene-drug interactions and on groups of genes interacting together. Based on a high-throughput genetic approach, we sought to identify a set of covariant single-nucleotide polymorphisms predictive of interindividual tacrolimus (Tac) dose requirement variability. Tac blood concentrations (Tac C0 ) of 229 kidney transplant recipients were repeatedly monitored after transplantation over 3 mo. Given the high dimension of the genomic data in comparison to the low number of observations and the high multicolinearity among the variables (gene variants), we developed an original predictive approach that integrates an ensemble variable-selection strategy to reinforce the stability of the variable-selection process and multivariate modeling. Our predictive models explained up to 70% of total variability in Tac C0 per dose with a maximum of 44 gene variants (p-value <0.001 with a permutation test). These models included molecular networks of drug metabolism with oxidoreductase activities and the multidrug-resistant ABCC8 transporter, which was found in the most stringent model. Finally, we identified an intronic variant of the gene encoding SLC28A3, a drug transporter, as a key gene involved in Tac metabolism, and we confirmed it in an independent validation cohort.

Long-Term Clinical Impact of Adaptation of Initial Tacrolimus Dosing to CYP3A5 Genotype.

Pretransplantation adaptation of the daily dose of tacrolimus to CYP3A5 genotype is associated with improved achievement of target trough concentration (C0 ), but whether this improvement affects clinical outcomes is unknown. In the present study, we have evaluated the long-term clinical impact of the adaptation of initial tacrolimus dosing according to CYP3A5 genotype: The transplantation outcomes of the 236 kidney transplant recipients included in the Tactique study were retrospectively investigated over a period of more than 5 years. In the Tactique study, patients were randomly assigned to receive tacrolimus at either a fixed dosage or a dosage determined by their genotype, and the primary efficacy end point was the proportion of patients for whom tacrolimus C0 was within target range (10-15 ng/mL) at day 10. Our results indicate that the incidence of biopsy-proven acute rejection and graft survival were similar between the control and the adapted tacrolimus dose groups, as well as between the patients who achieve the tacrolimus C0 target ranges earlier. Patients' death, cancer, cardiovascular events, and infections were also similar, and renal function did not change. We conclude that optimization of initial tacrolimus dose using pharmacogenetic testing does not improve clinical outcomes.

Severe cryptococcal-associated neurological immune reconstitution inflammatory syndrome in a renal transplant recipient treated with adalimumab.

Cryptococcosis is a major concern in organ transplant recipients. A decrease in immunosuppressants following the initiation of antifungal therapy is currently recommended, but can occasionally be complicated by the onset of immune reconstitution inflammatory syndrome (IRIS). We report on a case of cryptococcosis in a kidney transplant recipient, compounded by severe neurological IRIS, the outcome of which was unfavorable despite the use of anti-tumor necrosis factor-alpha monoclonal antibodies.

[Renal lymphangiectasia, a rare case of perirenal infiltration]. / La lymphangiectasie rénale, un cas rare d'infiltration périrénale.

Renal lymphangiectasia is a bilateral cystic infiltration of the perirenal and parapelvic space which is caused by the obstruction of the renal lymphatic tissue. To our knowledge only numbers have been reported in the literature. Renal lymphangiectasia usually asymptomatic and incidentally diagnosed has absolutely no effect on the patient outcome. Radiological imaging is typical so that the diagnosis does not need to be confirmed by a cyst punction. The lack of knowledge concerning renal lymphangiectasia make it usually confused with another cause of polycystic renal infiltration, such as the polycystic kidney disease. We report herein a case of renal lymphangiectasia diagnosed incidentally by an abdominal ultrasonography.

Fumagillin-induced aseptic meningoencephalitis in a kidney transplant recipient with microsporidiosis.

Microsporidiosis is an opportunistic infection in organ transplant recipients and patients with other cellular immunodeficiency. Fumagillin is an effective treatment against Enterocytozoon bieneusi, one of the two main species causing the microsporidiosis involved in human diseases. We report the first case, to our knowledge, of a probable drug-induced aseptic meningoencephalitis, after administration of fumagillin in a kidney transplant recipient with microsporidiosis.

Five-year results of a randomized trial comparing de novo sirolimus and cyclosporine in renal transplantation: the SPIESSER study.

Calcineurin inhibitors improve acute rejection rates and short-term graft survival in renal transplantation, but their continuous use may be deleterious. We evaluated the 5-year outcomes of sirolimus (SRL) versus cyclosporine (CsA) immunosuppressive treatment. This observational study was an extension of the SPIESSER study where deceased donor kidney transplant recipients were randomized before transplantation to a SRL- or CsA-based regimen and followed up 1 year. Data from 131 (63 SRL, 68 CsA) out of 133 patients living with a functional graft at 1 year were collected retrospectively at 5 years posttransplant. Seventy percent of CsA patients versus 54% of SRL patients were still on the allocated treatment at 5 years (p = 0.091), most discontinuations in each group being due to safety issues. In intent-to-treat, mean MDRD eGFR was higher with SRL: 54.2 versus 45.3 mL/min with CsA (p = 0.019); SRL advantage was greater in on-treatment analyses. There were no differences for patient survival (p = 0.873), graft survival (p = 0.121) and acute rejection (p = 0.284). Adverse events were more frequent with SRL (80% vs. 60%, p = 0.015). Results confirmed the high SRL discontinuation rate due to adverse events. Nevertheless, a benefit was evidenced on renal function in patients (more than 50%) still on treatment at 5 years.

The influence of cytomegalovirus infections on patient and renal graft outcome: a 3-year, multicenter, observational study (Post-ECTAZ Study).

Cytomegalovirus (CMV) infections posttransplant may increase the risk of acute rejection, graft failure, patient death, opportunistic infections, malignancy, diabetes, and cardiovascular complications. ECTAZ, a multicenter, randomized trial compared safety and efficacy at 12 months (M12) of two doses daclizumab (54 patients, group D) with thymoglobulin (55 patients, group T), plus cyclosporine (CsA), mycophenolate mofetil and steroids in first cadaveric kidney transplant patients. D+/R- patients received oral ganciclovir prophylaxis for 90 days. Post-ECTAZ is a 36-month, multicenter, observational study including recipients who participated in ECTAZ trial. We studied the indirect effects of CMV infections, whether recipients experienced (CMVi+) or not (CMVi-) a CMV infection/syndrome/disease. We compared 49 patients in the group CMVi+ with 54 patients in the group CMVi-. At month 36 (M36), patient survival, graft survival and renal function were comparable. The incidence of biopsy-proven acute rejection was 16.3% in the CMVi+ group versus 24.1% in the CMVi- group (not significant). The incidence of infections was increased in the CMVi+ group (P = .004), but not diabetes, malignancies, and cardiovascular complications. Our study shows at M36 that CMV infection/syndrome/disease episodes were associated with a higher incidence of infections but no difference for other long-term complications. Our data suggest that anti-CMV prophylaxis could decrease the risk for long-term related CMV complications.

Efficacy and safety of early cyclosporine conversion to sirolimus with continued MMF-four-year results of the Postconcept study.

Calcineurin inhibitor (CNI) withdrawal has been used as a strategy to improve renal allograft function. We previously reported that conversion from cyclosporine A (CsA) to sirolimus (SRL) 3 months after transplantation significantly improved renal function at 1 year. In the Postconcept trial, 77 patients in the SRL group and 85 in the CsA group were followed for 48 months. Renal function (Cockcroft and Gault) was significantly better at month 48 (M48) in the SRL group both in the intent-to-treat population (ITT): 62.6 mL/min/1.73 m(2) versus 57.1 mL/min/1.73 m(2) (p = 0.013) and in the on-treatment population (OT): 67.5 mL/min/1.73 m(2) versus 57.4 mL/min/1.73 m(2) (p = 0.002). Two biopsy proven acute rejection episodes occurred after M12 in each group. Graft and patient survival were comparable (graft survival: 97.4 vs. 100%; patient survival: 97.4 vs. 97.6%, respectively). The incidence of new-onset diabetes was numerically increased in the SRL group (7 vs. 2). In OT, three cancers occurred in the SRL group versus nine in the CsA group and mean proteinuria was increased in the SRL group (0.42 ± 0.44 vs. 0.26 ± 0.37; p = 0.018). In summary, the renal benefits associated with conversion of CsA to SRL, at 3 months posttransplantation, in combination with MMF were maintained for 4 years posttransplantation.

Complicated lymphoceles after kidney transplantation.

Lymphocele is a common surgical complication after renal transplantation. The incidence of lymphocele ranges from 0.6% to 18%. The aim of this study was to determine incidence, risk factors and prognosis of complicated lymphocele in the era of modern immunosuppression. We retrospectively reviewed 311 renal transplants from January 2003 to September 2008, we excluding patients who received sirolimus or underwent multiorgan transplantations. A complicated lymphocele was defined by the requirement for a surgical procedure for cure. Of the 311 transplant recipients, we included 269 in the study with 49 (18.9%) presenting a complicated lymphocele after transplantation. Cold ischemia time, waiting time on dialysis, gender, donor source, induction therapy (thymoglobulin vs basiliximab), and dialysis modality were similar between the 2 groups. Mycophenolate mofetil (MMF) doses were higher among the lymphocele than the nonlymphocele group (2.7 ± 0.54 g/d vs 2.36 ± 0.68 g/d; P < .05). However, the areas under the concentration-time curves of mycophenolic acid were not significantly different between the 2 groups (43.7 ± 15.3 h·mg/L vs 48 ± 21 h·mg/L; P = .33). However, a multivariate analysis showed complicated lymphocele to be associated with greater MMF doses (odds ratio [OR] 2.75; P < .01), warm ischemia time (OR 1.035; P < .05), and recipient age (OR 1.04; P < .05). In conclusion, we identified high MMF doses as an independent risk factor for lymphocele formation after renal transplantation.

Eculizumab: safety and efficacy after 17 months of treatment in a renal transplant patient with recurrent atypical hemolytic-uremic syndrome: case report.

In a recent study, eculizumab, a humanized monoclonal antibody which targets complement factor C5, appeared to resolve hemolysis and thrombocytopenia leading to recovery of renal function in a transplant patient during an episode of an atypical hemolytic uremic syndrome. We report the efficacy of eculizumab in a patient who presented with a recurrence of atypical hemolytic syndrome at 3 years after renal transplantation. After 17 months of eculizumab treatment, and without concomitant plasma therapy, renal function was maintained, the need for blood transfusions reduced, and acute thrombotic microangiopathy and hemolysis controlled. These data suggested that eculizumab should be considered to be a permanent treatment for this patient.

Interstitial fibrosis quantification in renal transplant recipients randomized to continue cyclosporine or convert to sirolimus.

Conversion from cyclosporine (CsA) to sirolimus at week 12 after kidney transplantation is associated with a significant improvement in renal function. The aim of this analysis was to investigate the effect of this conversion on interstitial fibrosis (IF), a hallmark of chronic allograft injury, in patients taking part in the CONCEPT trial. This multicenter, prospective, trial included 193 renal recipients randomized at week 12 to switch from CsA to sirolimus or to continue CsA, with mycophenolate mofetil. Routine biopsy with automated, quantified assessment of IF by a program of color segmentation was performed at 1 year in 121 patients. At 1 year, renal function was significantly improved in the conversion group as assessed by estimated GFR (MDRD) and measured GFR. Biopsy results, however, showed no between-group difference in percentage of IF. Calculated GFR at 1 year was significantly associated with the percentage of IF (p = 0.004, R(2)= 0.07). By multivariate analysis diabetic patients had more fibrosis than non-diabetic patients. In conclusion, although kidney transplant patients converted from CsA to sirolimus showed significant improvement in renal function, we found no difference of IF on 1-year biopsies.

[Medical and economic evaluation of new peritoneal dialysis solutions]. / Evaluation médico-économique des nouvelles solutions en dialyse péritonéale.

Conventional peritoneal dialysis solutions are mostly bioincompatible in relationship with a low pH, a high glucose and glucose degradation products (GDP) concentrations inducing anatomical and functional peritoneal membrane alterations. Use of icodextrin solution instead of glucose hypertonic solution preserves peritoneal membrane minimizing glucose exposure and its peritoneal absorption. Physiological fluids with a neutral pH and less GDP seem to have a positive effect on residual renal function which declines more slowly when they are early prescribed, before highly damaged and sclerotic kidneys. Preliminary data show that patients and technique survivals are better when physiological solutions are used either for diabetic and non diabetic patients. However, these new solutions do not improve peritonitis rates except for bicarbonate solutions but this fact must still be confirmed by other studies. In spite of a higher cost, physiological solutions must be proposed mainly for patients with a low comorbidity index and a high life expectancy.

Efficacy on renal function of early conversion from cyclosporine to sirolimus 3 months after renal transplantation: concept study.

Sirolimus (SRL) allows to minimize the use of cyclosporine (CsA), but de novo administration after transplantation is associated with various complications. We report a prospective, open-label, multicenter randomized study to evaluate conversion from a CsA-based regimen to a SRL-based regimen 3 months after transplantation. One hundred ninety-two of a total of 237 patients were eligible at 3 months to be converted to SRL (n = 95) or to continue CsA (n = 97). All patients were also given mycophenolate mofetil (MMF) and oral steroids, planned to be discontinued at month 8. The primary endpoint, the clearance estimated according to Cockcroft and Gault at week 52, was significantly better in the SRL group (68.9 vs. 64.4 mL/min, p = 0.017). Patient and graft survival were not statistically different. The incidence of acute rejection episodes, mainly occurring after withdrawal of steroids, was numerically but not statistically higher in the SRL group (17% vs. 8%, p = 0.071). Sixteen patients discontinued SRL, mainly for adverse events (n = 11), and seven patients discontinued CsA for renal failure or acute rejection. Significantly, more patients in the SRL group reported aphthous, diarrhea, acne and high triglyceride levels. Conversion CsA to SRL 3 months after transplantation combined with MMF is associated with improvement in renal function.

Cyclosporine monitoring in peripheral blood mononuclear cells: feasibility and interest. A prospective study on 20 renal transplant recipients.

Cyclosporine (CsA) has potent immunosuppressive properties, reflecting its ability to block the transcription of cytokine genes (mainly interleukin 2) in CD4+ T lymphocytes, markedly improving transplantation outcomes in the past 20 years. CsA pharmacokinetic variability and renal toxicity require whole blood (WB) monitoring by 4-hour area under the drug concentration curves (AUC0-4) or 2-hour postdose concentration (C2) monitoring. Nevertheless, graft rejection can occur despite target blood levels, suggesting that WB monitoring does not guarantee optimal immunosuppression. For a decade, pharmacologists and clinicians have worked to optimize CsA doses; some authors, inspired by its mechanism of action, have proposed therapeutic drug monitoring using peripheral blood mononuclear cells (PBMC; lymphocytes and monocytes). The aim of this study was to assess the feasibility and interest of CsA monitoring in PBMC ([CsA]PBMC). We also measured in vitro distribution of CsA in CD4+ and CD4- subsets.

Individualized mycophenolate mofetil dosing based on drug exposure significantly improves patient outcomes after renal transplantation.

Efficacy and safety of mycophenolate mofetil (MMF) may be optimized with individualized doses based on therapeutic monitoring of its active metabolite, mycophenolic acid (MPA). In this 12-month study, 137 renal allograft recipients from 11 French centers receiving basiliximab, cyclosporine A, MMF and corticosteroids were randomized to receive either concentration-controlled doses or fixed-dose MMF. A novel Bayesian estimator of MPA AUC based on three-point sampling was used to individualize doses on posttransplant days 7 and 14 and months 1, 3 and 6. The primary endpoint was treatment failure (death, graft loss, acute rejection and MMF discontinuation). Data from 65 patients/group were analyzed. At month 12, the concentration-controlled group had fewer treatment failures (p = 0.03) and acute rejection episodes (p = 0.01) with no differences in adverse event frequency. The MMF dose was higher in the concentration-controlled group at day 14 (p < 0.0001), month 1 (p < 0.0001) and month 3 (p < 0.01), as were median AUCs on day 14 (33.7 vs. 27.1 mg*h/L; p = 0.0001) and at month 1 (45.0 vs. 30.9 mg*h/L; p < 0.0001). Therapeutic MPA monitoring using a limited sampling strategy can reduce the risk of treatment failure and acute rejection in renal allograft recipients 12 months posttransplant with no increase in adverse events.

Sirolimus versus cyclosporine in kidney recipients receiving thymoglobulin, mycophenolate mofetil and a 6-month course of steroids.

To evaluate the efficacy and tolerance of a calcineurin inhibitor (CNI)-free regimen, 145 renal recipients were prospectively randomized to receive either sirolimus (n = 71) or cyclosporine (CsA; n = 74). All patients received polyclonal antilymphocyte antibodies, mycophenolate mofetil (MMF) and steroids (6 months). The primary endpoint, estimated glomerular filtration rate (eGFR) was not significantly different at 12 months comparing sirolimus- and CsA-treated patients (60 +/- 27 vs. 57 +/- 21 mL/min). At 12 months, patient and graft survival, incidence of biopsy-proven rejection and rates of steroid withdrawal were not statistically different (97% vs. 97%; 90% vs. 93%; 14.3% vs. 8.6% and 82.8% vs. 84.1%, respectively). Delayed and slow graft function (SGF) was not significantly different (18.6% vs. 12.3% and 11.4% vs. 13.7%, respectively). In patients who remained on treatment according to protocol at 12 months, eGFR was significantly higher with sirolimus (69 +/- 19 vs. 60 +/- 14 mL/min, p = 0.01). Overall study drug discontinuation rates were 28.2% with sirolimus and 14.9% with CsA. Adverse events (wound complications, mouth ulcers, diarrhea, hypokalemia, bronchopneumonia) and proteinuria >0.5 g/24h (38.8% vs. 5.6%, p < 0.001) were significantly more frequent in sirolimus-treated patients. Cytomegalovirus (CMV) infections were significantly less frequent with sirolimus (6% vs. 23%, p < 0.01). A CNI-free regimen using sirolimus-MMF can achieve excellent renal function, but patients on sirolimus experienced a high rate of adverse events and study drug discontinuation.

The evolution of weight and body composition in renal transplant recipients: Two-year longitudinal study.

UNLABELLED: Previous series have reported weight gain after kidney transplantation. However few studies have investigated the body composition after kidney transplantation, particularly during longitudinal follow-up. In this prospective study, we assessed the changes in body composition after kidney transplantation. We also analyzed the effect of steroid withdrawal from the immunosuppressive regimen on weight gain and body composition. METHODS: Thirty-eight cadaveric kidney transplant recipients were followed for 2 years posttransplant. Total and segmental body composition were measured by dual energy X-ray absorptiometry (DEXA) at the time of transplantation as well as 3, 6, 12, and 24 months later. RESULTS: In 28 patients (group A), prednisone was stopped by month 6, whereas, in 10 patients (group B), it was continued throughout the study. In the overall patient group, there were no significant changes in body weight. However, a trend to increased weight was observed in group B. In this group, patients showed an early increase in total body fat with a central accumulation of fat mass that was maintained during the follow-up period. On the other hand, total lean mass increased significantly in group A but did not change significantly in group B. CONCLUSION: In summary, overall the group showed no major changes in body weight during the 2 years after transplantation. Steroid withdrawal in kidney transplant recipients may have a significant positive effect on body composition.

Long-term results of monoclonal anti-Il2-receptor antibody versus polyclonal antilymphocyte antibodies as induction therapy in renal transplantation.

We compared the influence of induction therapy on 5-year patient and graft survival as well as on renal function in 100 kidney graft recipients at low immunological risk treated with antilymphocyte globulin (n = 50) versus anti-IL-2R monoclonal antibody (n = 50) in a prospective multicenter study. Long-term immunosuppressive treatment included cyclosporine, mycophenolate mofetil, and a short course of steroids in all patients. Five year graft (86% vs 86%) and patient (94% vs 94%) survivals were identical in both study arms. Moreover, neither serum creatinine or proteinuria were significantly different between the two groups. Our results showed that the choice of the induction therapy seemed to not have a major impact on long-term outcomes among renal recipients at low immunological risk.