Ingeborg A. Hauser

The Efficacy and Safety of 200 Days Valganciclovir Cytomegalovirus Prophylaxis in High-Risk Kidney Transplant Recipients

Late‐onset cytomegalovirus (CMV) disease is a significant problem with a standard 3‐month prophylaxis regimen. This multicentre, double‐blind, randomized controlled trial compared the efficacy and safety of 200 days’ versus 100 days’ valganciclovir prophylaxis (900 mg once daily) in 326 high‐risk (D+/R–) kidney allograft recipients. Significantly fewer patients in the 200‐day group versus the 100‐day group developed confirmed CMV disease up to month 12 posttransplant (16.1% vs. 36.8%; p < 0.0001). Confirmed CMV viremia was also significantly lower in the 200‐day group (37.4% vs. 50.9%; p = 0.015 at month 12). There was no significant difference in the rate of biopsy‐proven acute rejection between the groups (11% vs. 17%, respectively, p = 0.114). Adverse events occurred at similar rates between the groups and the majority were rated mild‐to‐moderate in intensity and not related to study medication. In conclusion, this study demonstrates that extending valganciclovir prophylaxis (900 mg once daily) to 200 days significantly reduces the incidence of CMV disease and viremia through to 12 months compared with 100 days’ prophylaxis, without significant additional safety concerns associated with longer treatment. The number needed to treat to avoid one additional patient with CMV disease up to 12 months posttransplant is approximately 5.

CC chemokine receptor 5 and renal-transplant survival

BACKGROUND About 1% of white populations are homozygous carriers of an allele of the gene for the CC chemokine receptor 5 (CCR5) with a 32 bp deletion (CCR5Delta32), which leads to an inactive receptor. During acute and chronic transplant rejection, ligands for CCR5 are upregulated, and the graft is infiltrated by CCR5-positive mononuclear cells. We therefore investigated the influence of CCR5Delta32 on renal-transplant survival. METHODS Genomic DNA from peripheral-blood leucocytes of 1227 renal-transplant recipients was screened by PCR for the presence of CCR5Delta32. Demographic and clinical data were extracted from hospital records. Complete follow-up data were available for 576 recipients of first renal transplants. Graft survival was analysed by Fishers exact test and Kaplan-Meier plots compared with a log-rank test. FINDINGS PCR identified 21 patients homozygous for CCR5Delta32 (frequency 1.7%). One patient died with a functioning graft. Only one of the remaining patients lost transplant function during follow-up (median 7.2 years) compared with 78 of the 555 patients with a homozygous wild-type or heterozygous CCR5Delta32 genotype. Graft survival was significantly longer in the homozygous CCR5Delta32 group than in the control group (log-rank p=0.033; hazard ratio 0.367 [95% CI 0.157-0.859]). INTERPRETATION Patients homozygous for CCR5Delta32 show longer survival of renal transplants than those with other genotypes, suggesting a pathophysiological role for CCR5 in transplant loss. This receptor may be a useful target for the prevention of transplant loss.

Up-regulation of Multidrug Resistance P-glycoprotein via Nuclear Factor-κB Activation Protects Kidney Proximal Tubule Cells from Cadmium- and Reactive Oxygen Species-induced Apoptosis

Cadmium-mediated toxicity of cultured proximal tubule (PT) cells is associated with increased production of reactive oxygen species (ROS) and apoptosis. We found that cadmium-dependent apoptosis (Hoechst 33342 and annexin V assays) decreased with prolonged CdCl2 (10 μm) application (controls: 2.4 ± 1.6%; 5 h: +5.1 ± 2.3%, 20 h: +5.7 ± 2.5%, 48 h: +3.3 ± 1.0% and 72 h: +2.1 ± 0.4% above controls), while cell proliferation was not affected. Reduction of apoptosis correlated with a time-dependent up-regulation of the drug efflux pump multidrug resistance P-glycoprotein (mdr1) in cadmium-treated cells (≈4-fold after 72 h), as determined by immunoblotting with the monoclonal antibody C219 and measurement of intracellular accumulation of the fluorescent probe calcein ± the mdr1 inhibitor PSC833 (0.5 μm). When mdr1 inhibitors (PSC833, cyclosporine A, verapamil) were transiently added to cells with mdr1 up-regulation by pretreatment for 72 h with cadmium, cadmium-induced apoptosis increased significantly and to a percentage similar to that obtained in cells with no mdr1 up-regulation (72-h cadmium: 5.2 ± 0.9%versus 72-h cadmium + 1-h PSC833: 7.2 ± 1.4%;p ≤ 0.001). Cadmium-induced apoptosis and mdr1 up-regulation depended on ROS, since co-incubation with the ROS scavengers N-acetylcysteine (15 mm) or pyrrolidine dithiocarbamate (0.1 mm) abolished both responses. Moreover, cadmium- and ROS-associated mdr1 up-regulation was linked to activation of the transcription factor NF-κB;N-acetylcysteine, pyrrolidine dithiocarbamate, and the IκB-α kinase inhibitor Bay 11-7082 (20 μm) prevented both, mdr1 overexpression and degradation of the inhibitory NF-κB subunit, IκB-α, induced by cadmium. The data show that 1) cadmium-mediated apoptosis in PT cells is associated with ROS production, 2) ROS increase mdr1 expression by a process involving NF-κB activation, and 3) mdr1 overexpression protects PT cells against cadmium-mediated apoptosis. These data suggest that mdr1 up-regulation, at least in part, provides anti-apoptotic protection for PT cells against cadmium-mediated stress.

A Randomized, Multicenter Study of Steroid Avoidance, Early Steroid Withdrawal or Standard Steroid Therapy in Kidney Transplant Recipients

In a randomized, open‐label, multicenter study, de novo renal transplant patients received no steroids (n = 112), steroids to day 7 (n = 115), or standard steroids (n = 109) with cyclosporine microemulsion (CsA‐ME), enteric‐coated mycophenolate sodium (EC‐MPS) and basiliximab. The primary objective, to demonstrate noninferiority of 12‐month GFR in the steroid‐free or steroid‐withdrawal groups versus standard steroids, was not met in the intent‐to‐treat population. However, investigational groups were not inferior to standard steroids in the observed‐case analysis. Median 12‐month GFR was not significantly different in the steroid‐free or steroid‐withdrawal groups (58.6 mL/min/1.73 m2 and 59.1 mL/min/1.73 m2) versus standard steroids (60.8 mL/min/1.73 m2). The 12‐month incidence of biopsy‐proven acute rejection (BPAR), graft loss or death was 36.0% in the steroid‐free group (p = 0.007 vs. standard steroids), 29.6% with steroid withdrawal (N.S.) and 19.3% with standard steroids. BPAR was significantly less frequent with standard steroids than either of the other two regimens. Reduced de novo use of antidiabetic and lipid‐lowering medication, triglycerides and weight gain were observed in one or both steroid‐minimization group versus standard steroids. For standard‐risk renal transplant patients receiving CsA‐ME, EC‐MPS and basiliximab, steroid withdrawal by the end of week 1 achieves similar 1‐year renal function to a standard‐steroids regimen, and may be more desirable than complete steroid avoidance.

ABCB1 Genotype of the Donor but Not of the Recipient Is a Major Risk Factor for Cyclosporine-Related Nephrotoxicity after Renal Transplantation

Cyclosporine (CsA) nephrotoxicity is a severe complication in organ transplantation because it leads to impaired renal function and chronic allograft nephropathy, which is a major predictor of graft loss. Animal models and in vivo studies indicate that the transmembrane efflux pump P-glycoprotein contributes substantially to CsA nephrotoxicity. It was hypothesized that the TT genotype at the ABCB1 3435C-->T polymorphism, which is associated with decreased expression of P-glycoprotein in renal tissue, is a risk factor for developing CsA nephrotoxicity. In a case-control study, 18 of 97 patients developed CsA nephrotoxicity and showed complete recovery of renal function in all cases when switched to a calcineurin inhibitor-free regimen. Both recipients and donors were genotyped for ABCB1 polymorphisms at the positions 3435C-->T and 2677G-->T/A. For controlling for population stratification, two additional polymorphisms, CYP2D6*4 and CYP3A5*3, with intermediate allelic frequencies were studied. The P-glycoprotein low expressor genotype 3435TT only of renal organ donors but not of the recipients was overrepresented in patients with CsA nephrotoxicity as compared with patients without toxicity (chi2 = 10.5; P = 0.005). CsA dosage, trough levels, and the concentration per dose ratio were not different between the patient groups. In a multivariate model that included several other nongenetic covariates, only the donors ABCB1 3435TT genotype was strongly associated with CsA nephrotoxicity (odds ratio, 13.4; 95% confidence interval, 1.2 to 148; P = 0.034). A dominant role of the donors ABCB1 genotype was identified for development of CsA nephrotoxicity. This suggests that P-glycoprotein is an important factor in CsA nephrotoxicity.

A randomized multicenter trial of the anti-ICAM-1 monoclonal antibody (enlimomab) for the prevention of acute rejection and delayed onset of graft function in cadaveric renal transplantation: a report of the European Anti-ICAM-1 Renal Transplant Study Group.

BACKGROUND T-cell activation through T-cell receptor engagement requires co-stimulatory molecules and also adhesion molecules such as ICAM-1. Moreover ICAM-1 mediates leukocyte invasion from the blood into tissue during inflammatory processes. In animal studies using mouse monoclonal antibodies against ICAM-1 (enlimomab), renal allograft survival has been improved and reperfusion damage from ischemia reduced. The European Anti-ICAM-1 Renal Transplant Study (EARTS) was a randomized, double-blind, parallel-group, placebo-controlled study lastingl year and performed in 10 transplant centers in Europe. METHODS A total of 262 recipients of cadaveric kidneys were given either enlimomab or a placebo for 6 days and were given triple immunosuppressive therapy of cyclosporine, azathioprine, and prednisolone. The primary efficacy endpoint was the incidence of the first acute rejection within 3 months, and each event was assessed by a committee including investigators and independent pathologists. RESULTS There was no significant difference in the incidences of first acute rejection at 3 months between the placebo and enlimomab groups (39% vs. 45%), and enlimomab did not reduce the risk of delayed onset of graft function (DGF) (26% vs. 31%). Neither was there a difference in patient survival (95% vs. 91%) or graft survival (89% vs. 84%) at 1 year. Fatal events occurred in 19 (7%) patients (7 placebo, 12 enlimomab). Clinically, the most important non-fatal adverse events were infections; however, there was no statistically significant difference between the incidences in the two groups (70% vs. 79%). CONCLUSION Short term enlimomab induction therapy after renal transplantation did not reduce the rate of acute rejection or DGF.

Extended valganciclovir prophylaxis in D+/R- kidney transplant recipients is associated with long-term reduction in cytomegalovirus disease: Two-year results of the impact study

Background. Whether the early reduction in cytomegalovirus (CMV) disease seen at 1 year with prolongation of antiviral prophylaxis (up to 200 days) persists in the long term is unknown. Methods. This international, randomized, prospective, double-blind study, compared 318 CMV D+/R− kidney transplant recipients receiving valganciclovir (900 mg) once daily for up to 200 days vs. 100 days. Long-term outcomes including CMV disease, acute rejection, graft loss, patient survival, and seroconversion were assessed. Results. At 2 years posttransplant, CMV disease occurred in significantly less patients in the 200- vs. the 100-day group: 21.3% vs. 38.7%, respectively (P<0.001). Between year 1 and 2, there were only 10 new cases of CMV disease; 7 in the 200-day group and 3 in the 100-day group. Patient survival was 100% in the 200-day group and 97% in the 100-day group (p=not significant). Biopsy-proven acute rejection and graft loss rates were comparable in both groups (11.6% vs. 17.2%, P=0.16, and 1.9% vs. 4.3%, P=0.22, in the 200-day vs. 100-day groups, respectively). Seroconversion was delayed in the 200-day group but was similar to the 100-day group by 2 years posttransplant (IgM or IgG seroconversion; 55.5% in the 200-day group vs. 62.0% in the 100-day group at 2-years; P=0.26). Assessment of seroconversion at the end of prophylaxis was of limited utility for predicting late-onset CMV disease. Conclusion. Extending valganciclovir prophylaxis from 100 to 200 days is associated with a sustained reduction in CMV disease up to 2 years posttransplant.

Prediction of Acute Renal Allograft Rejection by Urinary Monokine Induced by IFN-γ (MIG)

Early diagnosis of acute allograft rejection (AR) is still decisive for long-term renal allograft survival. The aim of this study was to define the role of the chemokine monokine induced by IFN-γ (MIG) (CXCL9) and IFN-γ–inducible protein 10 (IP-10) (CXCL10) as early markers of AR in renal transplantation (NTX). In a prospective study, 69 de novo renal transplant recipients were monitored and urine samples were collected after NTX for a median of 29 d. In pH-adjusted urine, MIG and IP-10 were determined by modified ELISA. AR was clinically diagnosed in 15 of 69 recipients and confirmed by biopsy in 14 of 15 AR patients (Banff classification). Corresponding to CXCR3-positive infiltrates in renal tissue, urinary MIG was elevated in 14 of 15 AR patients with a median of 2809 pg/ml (quartile 25% and 75% = 870 and 13,000; n = 15), being significantly ( P P P

Valganciclovir prophylaxis versus preemptive therapy in cytomegalovirus-positive renal allograft recipients: 1-year results of a randomized clinical trial.

Background. Cytomegalovirus (CMV) prevention can be achieved by prophylaxis or preemptive therapy. We performed a prospective randomized trial to determine whether renal transplant recipients with a positive CMV serostatus (R+) had a higher rate of CMV infection and disease after transplantation when treated preemptively for CMV infection, compared with primary valganciclovir prophylaxis. Methods. Prophylaxis was 2×450 mg oral valganciclovir/day for 100 days; preemptive patients were monitored by CMV-polymerase chain reaction (PCR), and after a positive PCR test received 2×900 mg valganciclovir/day for at least 14 days followed by secondary prophylaxis. Valganciclovir dosage was adjusted according to renal function. Patients are followed up for 5 years and initial 12-month data are presented. Two hundred and ninety-six recipients were analyzed (168 donor/recipient seropositive [D+/R+], 128 donor seronegative/recipient seropositive [D−/R+]; 146 receiving prophylaxis and 150 preemptive therapy). Results. Overall, CMV infection (asymptomatic CMV viral load ≥400 CMV DNA copies/mL proven by CMV-PCR) was significantly higher in recipients under preemptive therapy (38.7% vs. 11.0%, P<0.0001), with the highest incidence in D+/R+ preemptive patients (53.8% vs. 15.6%, P<0.0001). D+/R+ recipients with preemptive therapy also had the highest rate of CMV disease (CMV syndrome and tissue-invasive disease that was clinically diagnosed and biopsy proven) (19.2% vs. 4.4%, P=0.003). Renal function assessed by creatinine clearance was similar for both groups. Graft loss occurred in 7 vs. 4 patients on preemptive versus prophylactic therapy (P>0.05). Tolerability was similar for both treatment groups. Conclusions. Oral valganciclovir prophylaxis significantly reduces CMV infection and disease, particularly for D+/R+ patients. Hence, our study supports routine prophylaxis for all D+/R+ recipients.

Effect of nitrendipine on renal function in renal-transplant patients treated with cyclosporin: a randomised trial

BACKGROUND Calcium antagonists such as nitrendipine reduce the effects of cyclosporin on renal haemodynamics, however, their long-term efficacy has not been established. We did a randomised trial to investigate the effects of nitrendipine on renal function in renal-transplant patients treated with cyclosporin. METHODS 253 renal-transplant patients were recruited: 52 normotensive patients (diastolic blood pressure <90 mm Hg) were assigned placebo and 57 nitrendipine 5 mg twice daily; 71 hypertensive patients (diastolic blood pressure >90 to <115 mm Hg) were assigned placebo and 73 nitrendipine 10 mg twice daily. Nitrendipine was increased to 20 mg twice daily if the target diastolic blood pressure (<90 mm Hg) was not achieved. The patients were seen once a month for 24 months; blood pressure and serum creatinine concentration were recorded at each visit. Analysis was by intention to treat. FINDINGS 63 patients were withdrawn (35 nitrendipine, 28 placebo). The mean serum creatinine concentration at baseline was slightly higher in the nitrendipine group (146.7 micromol/L [SE 4.42]) than in the placebo group (137.0 micromol/L [3.54]. At the 24-month endpoint or at dropout, serum creatinine concentration was significantly higher in the 123 patients in the placebo group than the 130 patients in the nitrendipine group (160.8 [7.1] vs 148.5 [5.3], p for effect of treatment=0.025, analysis of covariance in a two-way classification; 95% CI for difference -1.77 to -22.98). At study entry, the blood pressures of the placebo and the nitrendipine groups were almost identical. At 24 months, blood pressure was higher in the normotensive patients given a placebo than in those patients given nitrendipine. By contrast, blood-pressure values were similar in those hypertensive patients given a placebo and those given nitrendipine at the end of treatment. INTERPRETATION The calcium antagonist nitrendipine has no adverse effects on kidney function in renal-transplant patients with cyclosporin. The drug has a small but significant nephroprotective effect, that is independent of the drugs antihypertensive action.