Evaluation of cytomegalovirus prophylaxis in low and intermediate risk kidney transplant recipients receiving lymphocyte-depleting induction

Acute kidney injury in paediatric kidney transplant recipients

Acute kidney injury (AKI) in paediatric kidney transplant recipients is common. Infection including urinary tract infection (UTI) and rejection are the most common causes in children. Surgical complications often cause AKI early post-transplant, whereas BK polyomavirus nephropathy rarely occurs in the first month post-transplant. Understanding kidney physiology helps to appreciate the sensitivity of the allograft to AKI, more so than native kidneys. Although the cause of AKI is often multi-factorial, there may be an underlying process that is treatable. Eliciting the aetiology, in this regard, is of paramount importance. Pre-renal and post-renal causes of allograft dysfunction are important to distinguish from intrinsic kidney disease. Clinical information and examination of fluid balance, urine dipstick testing, blood tests, bladder and kidney transplant ultrasound, and kidney transplant biopsy remain vital assessment tools in narrowing the differential diagnosis. A careful prescribed and recreational drug history is always warranted as many drugs including supplements are nephrotoxic. Additional causes such as allograft rejection, recurrent disease, and calcineurin inhibitor toxicity need to be considered in cases of allograft dysfunction, which would not affect the native kidneys. Early detection and assessment of AKI is crucial in promoting recovery. Significant progress has been made in specific pathologies over the last 20 years, which has improved kidney allograft survival rates considerably. Research into identifying AKI biomarkers to assist early diagnosis, before the serum creatinine rises, is ongoing.

Valacyclovir versus valganciclovir for cytomegalovirus prophylaxis in kidney transplant recipients: a systematic review and comparative meta-analysis

Background

Valganciclovir (ValG) is the most widely used drug for cytomegalovirus (CMV) prophylaxis in kidney transplant recipients (KTRs). However, it is associated with dose-limiting side effects and considerable costs. Some centers have identified valacyclovir (ValA) as an economically attractive alternative with a lower risk of bone marrow suppression. The comparative effectiveness of these two drugs is not well-established. This study aims to compare the efficacy and safety of ValA and ValG for CMV prophylaxis in KTRs.

Methods

Searches were conducted of the Medline, Cochrane, Web of Science, Embase, and Ovid databases. Endpoints encompassed the incidence of CMV disease, CMV viremia, acute rejection, leukopenia/neutropenia, and other infections, including BK polyomavirus and non-CMV herpesviruses (HVs). Risk ratios (RRs) with 95% confidence intervals (CIs) were pooled using a random-effects model.

Results

Six studies, comprising 888 patients (438 receiving ValA), were included. The groups were comparable in CMV viremia incidence (RR, 0.70; 95% CI, 0.31-1.57; P=0.4) and the development of CMV disease (RR, 0.74; 95% CI, 0.09-5.97; P=0.8). No significant differences in acute rejection rates were observed (RR, 0.97; 95% CI, 0.50-1.91; P=0.8). However, the rate of leukopenia/neutropenia was significantly lower in the ValA group (RR, 0.57; 95% CI, 0.42-0.77; P<0.01). No significant differences were noted for BK viremia (RR, 0.67; 95% CI, 0.24-1.87; P=0.4) or other HV infections (RR, 1.43; 95% CI, 0.61-3.38; P=0.4).

Conclusions

The drugs demonstrate comparable efficacy in preventing CMV infection following kidney transplantation. However, ValA may have a lower impact on bone marrow suppression.

Tailoring cytomegalovirus prophylaxis based on T cell immunity panel assessment in kidney transplant patients at high risk of cytomegalovirus

BACKGROUND

Valganciclovir prophylaxis against cytomegalovirus (CMV) is recommended for solid organ transplant recipients, but is associated with drawbacks, including expense and leukopenia. Our center adopted a strategy of serial assessment with a CMV-specific T cell immunity panel (CMV-TCIP) and cessation of valganciclovir prophylaxis upon demonstration of adequate CD4+ responses in kidney transplant patients at high risk of CMV disease.

METHODS

We retrospectively reviewed adult recipients of a kidney or pancreas transplant between August 2019 and July 2021 undergoing serial CMV-TCIP monitoring. Included patients were considered high risk for CMV, defined by donor positive (D+)/recipient negative (R-) CMV IgG serostatus, or recipient positive (R+) patients who received induction with a lymphocyte-depleting agent. Prophylaxis was discontinued after a patient's first CMV-specific CD4+ T cell value of ≥0.20%. Risk of clinically significant CMV infection (csCMVi) in those who underwent early discontinuation of CMV prophylaxis and predictors of CMV T cell immunity were analyzed.

RESULTS

Of 54 included patients, 22 stopped prophylaxis early due to CMV-specific CD4+ T cell immunity at a median of 4.7 (IQR: 3.8-5.4) months after transplant. No instances of csCMVi were observed in the 22 patients who had prophylaxis discontinued early, of whom 19/22 were CMV R+ and 3/22 were CMV D+/R-. Donor/recipient CMV serostatus was predictive of immunity (p <.001).

CONCLUSION

Early discontinuation of valganciclovir prophylaxis in patients with CMV CD4+ T cellular immunity appears safe and potentially beneficial in this preliminary series, especially in R+ patients. Further study is warranted, given that truncated prophylaxis may yield patient-level benefits.

Cytomegalovirus Matching in Deceased Donor Kidney Allocation: Results From a U.S. National Simulation Model

Background

Cytomegalovirus (CMV) infects >60% of adults and can pose an independent risk factor for allograft loss and mortality in solid organ transplant recipients. The purpose of this study is to evaluate the impact of a nationwide implementation of CMV seromatching (donor/recipient: D-/R- and D+/R+) in the U.S. deceased donor kidney allocation system (KAS).

Methods

Adult candidates on the U.S. kidney-only transplant waiting list and deceased donor kidneys offered to the U.S. transplant centers were considered. A discrete-event simulation model, simulating the pre-COVID-19 period from January 1, 2015, to January 1, 2018, was used to compare the performances of currently employed KAS-250 policy (without CMV matching) to various simulated CMV matching policies parameterized by calculated panel reactive antibody exception threshold. Outcomes included CMV serodistribution, waiting time, access to transplantation among various groups, transplant rate, graft survival, kidney discard rate, and antigen-mismatch distribution, stratified by CMV serostatus.

Results

CMV matching policy with a calculated panel reactive antibody exception threshold of 50% (namely, the CMV">50%" policy) strikes a better balance between benefits and drawbacks of CMV matching. Compared with KAS-250, CMV">50%" reduced CMV high-risk (D+/R-) transplants (6.1% versus 18.1%) and increased CMV low-risk (D-/R-) transplants (27.2% versus 13.1%); increased transplant rate for CMV R- patients (11.54 versus 12.57) but decreased for R+ patients (10.68 versus 10.48), yielding an increase in aggregate (11.09 versus 10.94); and reduced mean time to transplantation (by 6 wk); and reduced kidney discard rate (25.7% versus 26.2%).

Conclusions

Our findings underscore the feasibility and potential advantages of a nationwide CMV seromatching policy in kidney transplantation.

Efficacy and Safety of Antiviral Agents in Preventing Allograft Rejection Following CMV Prophylaxis in High-Risk Kidney Transplantation: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

Many antiviral agents have been studied in clinical trials for allograft rejection prevention following cytomegalovirus (CMV) prophylaxis in high-risk kidney transplant patients. However, data on the most effective and safest treatment are lacking. We conducted a systematic review and network meta-analysis to rank CMV prophylaxis agents for allograft rejection prevention following CMV prophylaxis in high-risk kidney transplant patients according to their efficacy and safety. We conducted searches on the MEDLINE, Embase, SCOPUS, and CENTRAL databases, as well as the reference lists of selected studies up to December 2021, for published and peer-reviewed randomized controlled trials assessing the efficacy of CMV prophylaxis agents in high-risk kidney transplant patients. Thirteen studies were independently selected by three reviewers and included post-kidney transplant patients indicated for CMV prophylaxis who had been randomized to receive prophylactic antiviral agents or standard of care. The reviewers independently extracted data from the included studies, and direct and network meta-analyses were applied to assess the study outcomes. The probability of efficacy and safety was evaluated, and the drugs were assigned a numerical ranking. We evaluated the risk of bias using the Cochrane Risk of Bias 2.0 tool. The primary outcome was an incidence of biopsy-proven acute rejection, whereas the secondary outcome was a composite of major adverse drug reactions. Each outcome referred to the definition provided in the original studies. Valganciclovir, valacyclovir, and ganciclovir were identified to significantly decrease the incidence of biopsy-proven acute rejection with pooled risk differences (RDs) of −20.53% (95% confidence interval [CI] = −36.09% to −4.98%), −19.3% (95% CI = −32.7% to −5.93%), and −10.4% (95% CI = −19.7% to −0.12%), respectively. The overall major adverse drug reaction was 5.7% without a significant difference when compared with placebo. Valganciclovir had the best combined efficacy and safety among the examined antiviral agents and was the most effective and safest antiviral agent overall for allograft rejection prevention following CMV prophylaxis. Valacyclovir was the optimal alternative antiviral agent for patients who were unable to tolerate intravenous ganciclovir or access oral valganciclovir as financial problem. However, compliance and dose-related toxicities should be closely monitored.