Cytomegalovirus Prophylaxis Research Articles

Role of letermovir therapeutic drug monitoring for cytomegalovirus prophylaxis in allogeneic hematopoietic stem cell transplantation recipients: a prospective study

Role of letermovir therapeutic drug monitoring for cytomegalovirus prophylaxis in allogeneic hematopoietic stem cell transplantation recipients: a prospective study

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

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

Crushing obstacles: A case series on alternative letermovir administration in transplant recipients.

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. Letermovir is used primarily for cytomegalovirus (CMV) prophylaxis in select hematopoietic cell or solid organ transplant recipients. The manufacturer has provided no guidance on whether letermovir can be crushed and administered via enteral tube. This study aimed to assess whether letermovir tablets could be manipulated (eg, through crushing) for enteral tube administration. This was a retrospective, single-center review of patients who received crushed letermovir tablets administered via enteral tube for at least 7 days, between April 2018 and August 2023. Data collection focused on demographics, transplant history, treatment characteristics associated with letermovir, and diagnosis of CMV viremia or disease. Fourteen patients met the inclusion criteria for the review and received crushed letermovir for a median of 19 days (range, 7 to 42 days). All patients were on letermovir as CMV prophylaxis, the majority of whom were lung transplant recipients. On the basis of CMV serostatus at the time of transplantation, 50% of patients were classified as being at high risk and the other 50% were in the intermediate-risk category for CMV disease. One patient developed low-level viremia with a CMV viral load of 254 IU/mL. No patients developed CMV infection or disease while receiving crushed letermovir. On the basis of this case series, manipulation of letermovir immediate-release tablets was proven to be safe and effective for patients. Crushing letermovir for administration via enteral tube should be considered as an option for patients who cannot tolerate administration via the oral route.

Drug-drug interactions between letermovir and tacrolimus in Japanese renal transplant recipients simulated using a physiologically based pharmacokinetic model.

Letermovir (LET) is a novel antiviral agent recently approved for cytomegalovirus (CMV) prophylaxis of renal transplant patients in Japan. However, its interactions with tacrolimus (TAC), an important immunosuppressant, remain ambiguous, warranting careful evaluation considering the unique genetic and physiological characteristics of Japanese patients. Therefore, in this study, we aimed to investigate the drug-drug interactions between LET and extended-release TAC (ER-TAC) in Japanese renal transplant patients via physiologically based pharmacokinetic (PBPK) modeling. We developed PBPK models for LET and TAC, including a new model for ER-TAC, using the Simcyp simulator. We also created a virtual Japanese post-transplant population by incorporating physiological parameters specific to Japanese patients, including CYP3A5 genotypes. Our model accurately predicted the pharmacokinetics of both immediate-release and ER-TAC co-administered with LET. In the Japanese population, LET significantly increased ER-TAC exposure, with the effect varying by CYP3A5 genotype. For CYP3A5*1 carrier, the area under the curve ratio ranged from 2.33 to 2.53, while for CYP3A5*3/*3 carriers, it ranged from 2.82 to 2.86. The maximum concentration ratio was approximately 1.50 across all groups. Our findings suggest reducing the ER-TAC dose by approximately 57-60% for CYP3A5*1 carrier and 65% for CYP3A5*3/*3 carriers when co-administered with LET for Japanese renal transplant patients. Moreover, the developed model incorporating population-specific factors, such as hematocrit values and CYP3A5 genotype frequencies, is a valuable tool to evaluate complex drug interactions and guide the dosing strategies for LET and TAC in Japanese patients. Overall, this study expands the application of PBPK modeling in transplant pharmacology, contributing to the development of effective immunosuppressive strategies for Japanese renal transplant patients.

Cytomegalovirus prophylaxis in pediatric liver transplantation: A comparison of strategies across the Society of Pediatric Liver Transplantation consortium

Although cytomegalovirus (CMV) is a common complication after pediatric liver transplantation (PLT), the optimal method for CMV prevention is uncertain and lacks multicentered investigation. We compared the effectiveness of short (<120 days) vs long (>180 days) CMV primary antiviral prophylaxis to prevent CMV disease in PLT, through a prospective cohort study of primary PLT (aged <18 years) recipients enrolled in the Society of Pediatric Liver Transplantation registry from 2015 to 2019 with either donor or recipient CMV seropositivity. Participants were grouped into short or long prophylaxis based on their center’s practice and intended duration. In total, 199 PLT recipients were enrolled including 112 (56.3%) short and 87 (43.7%) long prophylaxis. End-organ disease was rare and similar between groups (2.7% and 1.1%; P = .45). CMV DNAemia and syndrome were more common in the short compared with those in long prophylaxis (26.8% vs 13.8%; P = .03; 18.8% vs 6.9%; P = .02). Neutropenia occurred more commonly with long prophylaxis (55.2% vs 16.1%; P < .001). Graft and patient survival were similar. Consideration of a short prophylaxis must weigh increased risk of CMV syndrome/DNAemia against medication burden and neutropenia of longer prophylaxis.

Which allogeneic hematopoietic cell transplant recipients have an increased risk for delayed-onset clinically significant cytomegalovirus infection after letermovir prophylaxis?

Cytomegalovirus (CMV) reactivation is one of the most common complications after allogeneic hematopoietic stem cell transplantation (HSCT). Letermovir is approved for CMV prophylaxis among high-risk recipients. However, delayed-onset post-prophylaxis clinically significant CMV infection (csCMVi) has been observed, suggesting the potential for extending letermovir prophylaxis beyond the first one hundred days post-HSCT. Retrospective multicenter cohort study of allogeneic HSCT patients from August 2018 to March 2023. The primary aim of this study was to identify the risk factors at day 100 associated with delayed onset csCMVi, in patients who received letermovir prophylaxis up to day 100. Competing risk analysis was used to evaluate incidence with specific risk factors, using Gray's Test comparing groups for each event. Among 166 eligible allogeneic HSCT recipients, the most common primary hematological diagnosis was acute myelogenous leukemia (AML) (42.2%). Twenty-six (15.7%) developed a breakthrough csCMVi. Delayed-onset csCMVi occurred in 23.5%, at a median time of 133 days after SCT. On multivariate analysis, having a matched unrelated donor (odds ratio [OR] 2.46) and a CMV donor negative/recipient positive status (OR 3.47) were associated with delayed onset csCMVi. In contrast, AML had a lower odd of having delayed-onset csCMVi (OR 0.23). Having a matched unrelated donor, a CMV donor negative/recipient positive status, and a non-AML underlying disease were associated with delayed onset csCMVi. Prospective studies are needed to evaluate whether extended letermovir prophylaxis is beneficial for these patients.

Efficacy of Letermovir for Cytomegalovirus Prophylaxis Following Alemtuzumab T-Cell Depleted Allogeneic Hematopoietic Stem Cell Transplant

In vivo T-cell depletion (TCD) using alemtuzumab decreases the risk of Graft vs. Host Disease (GvHD) in recipients of allogeneic hematopoietic stem cell transplant (allo-HSCT). However, this approach increases the risk of infections post-allo-HSCT, including Cytomegalovirus (CMV). Letermovir is approved for the use in CMV prophylaxis post-allo-HSCT. Few studies have investigated the efficacy of letermovir in patients receiving alemtuzumab. This is a single-center retrospective study describing our institutional experience using letermovir in recipients of alemtuzumab TCD allo-HSCT from unrelated donors (URD). The primary outcome was the cumulative incidence of significant CMV infection (defined as viremia leading to preemptive antiviral therapy or CMV disease) within 100 days post-transplant. Secondary outcomes included the cumulative incidence of acute GvHD (grade ≥ 2), the cumulative incidence of extensive chronic GvHD, and overall survival. A total of 84 alemtuzumab TCD URD allo-HSCT recipients were included in the analysis, 30 of whom received letermovir (letermovir group) and 54 who did not receive letermovir (control group). The median age was 59 years (range: 26 - 75 years) and 55.5 years (range: 20 - 73 years) in the letermovir and control group, respectively. Most recipients (66.7%) in both groups received unrelated matched allografts, and myeloid neoplasms were the most common indication for allo-HSCT. A significantly lower cumulative incidence of significant CMV infection within 100 days was seen in the letermovir group compared to the control group (10.0% [95% CI: 2.5 - 23.9%] vs 55.6% [95% CI: 41.2 - 67.8%], p < 0.0001). There was no statistically significant difference in the incidence of acute GvHD (grade ≥ 2) or overall survival between the two groups. However, lower rates of extensive chronic GvHD were noted in the letermovir group (10.5% [95% CI: 2.6 - 24.9%] vs. 36.5% [95% CI: 23.6 - 49.5%], p=0.0126). These results demonstrate the efficacy of letermovir in decreasing the rates of clinically significant CMV infection in patients undergoing alemtuzumab T-cell depleted allo-HSCT.

The pharmacokinetics of ganciclovir during prolonged intermittent kidney replacement therapy in a cardiac transplant recipient.

Ganciclovir, a guanine analogue, is used intravenously (IV) first-line for the prophylaxis and treatment of cytomegalovirus (CMV) infection in solid organ transplant recipients. The pharmacokinetics (PK) of ganciclovir are highly variable, with myelosuppression occurring at high concentrations. Ganciclovir is primarily renally excreted as the parent compound, and clearance is significantly reduced in renal impairment. Acute kidney injury (AKI) is a common post-operative complication of cardiac transplantation, reducing the clearance of ganciclovir. In the intensive care unit (ICU), AKI is often managed by kidney replacement therapy (KRT). One form of KRT, prolonged intermittent kidney replacement therapy (PIKRT) is increasingly used for cost and flexibility advantages. Ganciclovir dosing recommendations are available for varying degrees of renal impairment and KRT, except for PIKRT. In this case of cardiac transplantation, complicated by anuric AKI, a ganciclovir dose of 2.0-2.5 mg/kg of adjusted body weight given after each PIKRT session was demonstrated to achieve PK targets.

Cell-mediated Immunity to Guide Primary Prophylaxis for CMV Infection in Organ Transplant Recipients: A Multicenter Single-arm Prospective Study.

There are few interventional studies using CMV cell-mediated immunity (CMI) to guide antiviral prophylaxis. We assessed the Quantiferon-CMV (QTF-CMV) assay to guide CMV prophylaxis duration in high-risk organ transplant recipients. A single-arm, multicenter, prospective interventional study including high-risk kidney, pancreas, liver, and heart transplant recipients who were either donor CMV-seropositive, recipient-seronegative (D+/R-) or recipient-seropositive with antithymocyte globulin (R+/ATG) induction. CMI testing was performed using the QTF-CMV assay at months 3, 4, 5, and 6 posttransplant. Prophylaxis was discontinued for a positive CMI but continued for a negative result up to a maximum of 6 mo. The primary endpoint was CMV viremia ≥1000 IU/mL up to 1 y posttransplant. One hundred eight patients were included, comprising kidney (n = 89), kidney-pancreas (n = 7), liver (n = 10), and heart (n = 2) transplants. Eighty-nine patients (82.4%) completed the study protocol (n = 39 D+/R- and n = 50 R+/ATG). In the D+/R- group, only 1 of 39 patients (2.6%) had a positive QTF-CMV result. In the R+/ATG group, 33 of 50 patients (66%) had a positive QTF-CMV result before 6 mo, allowing for early discontinuation of prophylaxis (28 at month 3, 4 at month 4, and 1 at month 5). During the follow-up, CMV viremia ≥1000 IU/mL occurred in only 4 of 33 patients (12.1%) who discontinued prophylaxis early compared with 6 of 17 patients (35.3%) with negative QTF-CMV results and continued prophylaxis (hazard ratio 0.31; 95% confidence interval, 0.09-1.09; P = 0.07). No R+ patient developed CMV disease. QTF-CMV-guided prophylaxis appears useful in R+ patients who may benefit from a tailored duration of prophylaxis. This strategy does not appear to be useful in D+/R- patients.

Letermovir use for cytomegalovirus prophylaxis following lung transplantation: A single-center review

Cytomegalovirus (CMV) remains a major cause of infection following solid organ transplant and valganciclovir prophylaxis is the standard of care. However, valganciclovir associated myelosuppression limits its tolerability and can require dose reduction in immunosuppression, particularly cell cycle inhibitors, or changes in antimicrobial prophylaxis. Letermovir, a viral terminase inhibitor, is approved by the FDA for use as CMV prophylaxis in kidney transplant recipients; data on its use in lung transplant recipients (LTRs) is limited. We performed a single-center retrospective cohort study of LTRs prescribed letermovir for prophylaxis between 1/1/18-9/1/23. Over the study period, 88 LTRs were prescribed letermovir with most (93%) switching due to myelosuppression while on valganciclovir. Of those prescribed letermovir, 67 (76%) actually started letermovir, with the primary barrier being insufficient insurance coverage or high copay cost. Among LTRs who started letermovir due to myelosuppression, 90% had improvement in their leukopenia or neutropenia, with a significant increase in white blood cell count one month after switching therapy (P<0.0001). Additionally, 46% of those who were not receiving a cell cycle inhibitor previously were able to restart this after switching to letermovir. CMV was detected in 14 LTRs following letermovir switch, with two discontinuing letermovir due to breakthrough CMV. Our findings support the use of letermovir for CMV prophylaxis in LTRs with possible benefits over valganciclovir, although a direct comparison is needed.

The Cost-effectiveness of Valganciclovir Prophylaxis Versus Preemptive Therapy in CMV R+ Kidney Transplant Recipients Over the First Year Posttransplantation.

In kidney transplant recipients with positive serology (R+) for the cytomegalovirus (CMV), 2 strategies are used to prevent infection, whose respective advantages over the other are still debated. This study aimed to evaluate the cost-effectiveness and cost utility of antiviral prophylaxis against CMV versus preemptive therapy, considering CMV infection-free survival over the first year posttransplantation as the main clinical outcome. Clinical, laboratory, and economic data were collected from 186 kidney transplant patients CMV (R+) included in the cohort study (85 patients who benefited from CMV prophylaxis and 101 from preemptive therapy). Costs were calculated from the hospital perspective and quality-adjusted life years (QALYs) using the EQ5D form. Using nonparametric bootstrapping, the incremental cost-effectiveness ratio (ICER) and cost utility were estimated (euros) for each case of infection avoided and each QALY gained for 1 y, respectively. Prophylaxis significantly decreased the risk of CMV infection over the first year posttransplantation (hazard ratio 0.22, 95% confidence interval = 0.12-0.37, P < 0.01). Compared with preemptive therapy, prophylaxis saved financial resources (€1155 per patient) and was more effective (0.42 infection avoided per patient), resulting in an ICER = €2769 per infection avoided. Prophylaxis resulted in a net gain of 0.046 in QALYs per patient and dominated over preemptive therapy with €1422 cost-saving for 1 QALY gained. This study shows that CMV prophylaxis, although considered as a more expensive strategy, is more cost-effective than preemptive therapy for the prevention of CMV infections in renal transplant patients. Prophylaxis had a positive effect on quality of life at reasonable costs and resulted in net savings for the hospital.

Real-world experience with letermovir for cytomegalovirus-prophylaxis after allogeneic hematopoietic cell transplantation: A multi-centre observational study

Efficacy and safety of letermovir as prophylaxis for clinically significant cytomegalovirus infections (csCVMi) was evaluated in randomised controlled trials while most of the real-world studies are single-centre experiences. We performed a retrospective, multi-centre case-control study at six German university hospitals to evaluate clinical experiences in patients receiving CMV prophylaxis with letermovir (n=200) compared to controls without CMV prophylaxis (n=200) during a 48-week follow-up period after allogeneic hematopoietic cell transplantation (aHCT). The incidence of csCMVi after aHCT was significantly reduced in the letermovir (34%, n=68) compared to the control group (56%, n=112; p<0.001). Letermovir as CMV prophylaxis (OR 0.362) was found to be the only independent variable associated with theprevention of csCMVi. Patients receiving letermovir showed significantly better survival compared to the control group (HR = 1.735, 95% CI: 1.111-2.712; p=0.014). Of all csCMVi, 46% (n=31) occurred after discontinuation of letermovir prophylaxis. Severe neutropenia (<500 neutrophils/µL) on the day of the stem cell infusion was the only independent variable for an increased risk of csCMVi after the end of letermovir prophylaxis. Our study highlights the preventive effects of letermovir on csCMVi after aHCT. A substantial proportion of patients developed a csCMVi after discontinuation of letermovir. In particular, patients with severe neutropenia require specific attention after drug discontinuation.

Real-World Safety and Effectiveness of Letermovir in Patients Undergoing Allogenic Hematopoietic Stem Cell Transplantation: Final Results of Post-Marketing Surveillance in Japan.

Cytomegalovirus (CMV) is a common opportunistic infection after allogenic hematopoietic stem cell transplantation (allo-HSCT). Letermovir, an inhibitor of CMV DNA terminase, is approved for CMV prophylaxis in allo-HSCT patients. We report the final results of post-marketing surveillance of letermovir in Japan. The case report forms were drafted in part by the Japanese Data Center for Hematopoietic Cell Transplantation using data elements in the Transplant Registry Unified Management Program and sent to individual HSCT centers to decrease the burden of reporting. Hematopoietic stem cell transplantation patients who received letermovir between May 2018 and May 2022 were registered. Data collected included physician-assessed adverse events/adverse drug reactions and clinical effectiveness (development of CMV disease, CMV antigen status, and use of preemptive therapy). A total of 821 HSCT patients were included in the safety analyses. Adverse drug reactions occurred in 11.33% of patients, with serious adverse drug reactions in 3.05%. The five most common adverse drug reactions were nausea (1.58%), renal impairment (1.46%), and acute graft versus host disease, CMV test positive, and hepatic function abnormal (0.61% each). A total of 670 patients were eligible for effectiveness analyses. Among these patients, 16.57% and 28.66% required preemptive therapy through week 14 and week 48, respectively. In addition, relatively few patients developed CMV disease throughout the follow-up period (1.34% at week 14 and 3.85% at week 48). This final analysis of post-marketing surveillance with up to 48 weeks follow-up period in Japan provides further evidence supporting the safety profile and effectiveness of letermovir for CMV prophylaxis in patients undergoing allo-HSCT in real-world settings.

Phenotypes of cytomegalovirus genetic variants encountered in a letermovir clinical trial illustrate the importance of genotyping validation

Emergence of drug resistance is rare after use of letermovir (LMV) as prophylaxis for post-transplant cytomegalovirus (CMV) infection. In a recent study involving renal transplant recipients, no known LMV resistance mutations were detected in those receiving LMV prophylaxis. However, uncharacterized viral amino acid substitutions were detected in LMV recipients by deep sequencing in viral subpopulations of 5%–7%, at codons previously associated with drug resistance: UL56 S229Y (n = 1), UL56 M329I (n = 9) and UL89 D344Y (n = 5). Phenotypic analysis of these mutations in a cloned laboratory CMV strain showed that S229Y conferred a 2-fold increase in LMV EC50, M329I conferred no LMV resistance, and D344Y knocked out viral viability that was restored after the nonviable clone was reverted to wild type D344. As in previous CMV antiviral trials, the detection of nonviable mutations, even in multiple study subjects, raises strong suspicion of genotyping artifacts and encourages the use of replicate testing for authentication of atypical mutation readouts. The non-viability of UL89 D344Y also confirms the biologically important locus of the D344E substitution that confers resistance to benzimidazole CMV terminase complex inhibitors, but does not feature prominently in LMV resistance.

High malignancy rate in the absence of viral prophylaxis after kidney transplantation in Sudan.

Kidney transplantation in Sudan is funded by the government. Cytomegalovirus prophylaxis is provided for patients who receive biological induction or have recipient-negative donor-positive cytomegalovirus serology. Doctor Selma Center for Kidney Diseases joined the national kidney transplant program in May 2019. Since then, we observed the frequent occurrence of cancer in patients who received modest immunosuppression without viral prophylaxis. We retrospectively divided kidney transplant recipients between 2019 and 2021 into two groups according to cytomegalovirus prophylaxis and compared tumor occurrence rates. The first group included 77 patients who did not receivebiological induction or cytomegalovirus prophylaxis. The second group included 92 patients who received valganciclovir for 3-6months. There was no other antiviral treatment except entecavir for chronic hepatitis B virus infection in eight patients. Five patients in the first group developed malignancy. The first patient presented eight months post-transplant with Kaposi sarcoma of the stomach and responded to treatment with sirolimus. The second patient presented nine months post-transplant with cutaneous Kaposi sarcoma and also responded to sirolimus. Two patients presented two and four months post-transplant with aggressive non-cutaneous Kaposi sarcoma that involved the gastrointestinal tract and lymphatic system and died soon afterwards. The fifth patient presented three years post-transplant with non-Hodgkin lymphoma of the duodenum and is currently receiving chemotherapy. Malignancy rate (6.5% vs 0.0%, P = 0.02) and Kaposi sarcoma rate (5.2% vs 0.0%, P = 0.04) were significantly higher in the first group. In Sudan, omitting valganciclovir prophylaxis after kidney transplantation was associated with a high rate of virus-induced malignancy.

Efficacy of valganciclovir 450 mg for cytomegalovirus prophylaxis in kidney transplant recipients: Retrospective cohort study single center experience

Efficacy of valganciclovir 450 mg for cytomegalovirus prophylaxis in kidney transplant recipients: Retrospective cohort study single center experience

Pre-Transplant Frequencies of FoxP3+CD25+ in CD3+CD8+ T Cells as Potential Predictors for CMV in CMV-Intermediate Risk Kidney Transplant Recipients.

Cytomegalovirus (CMV) infection detrimentally influences graft survival in kidney transplant recipients, with the risk primarily determined by recipient and donor serostatus. However, recipient CD8+ T cells play a crucial role in CMV control. The optimal preventive strategy (prophylaxis vs. pre-emptive treatment), particularly for seropositive (intermediate risk) recipients, remains uncertain. We investigated CD8+ T cell subpopulation dynamics and CMV occurrence (DNAemia ≥ 100IU/mL) in 65 kidney transplant recipients, collecting peripheral blood mononuclear cells before (T1) and 1year after transplantation (T2). Comparing the two timepoints, we found an increase in granulocyte, monocyte and CD3+CD8+ T cells numbers, while FoxP3+CD25+, LAG-3+ and PD-1+ frequencies were reduced at T2. CMV DNAemia occurred in 33 recipients (55.8%) during the first year. Intermediate risk patients were disproportionally affected by posttransplant CMV (N = 29/45, 64.4%). Intermediate risk recipients developing CMV after transplantation exhibited lower leukocyte, monocyte, and granulocyte counts and higher FoxP3+CD25+ frequencies in CD3+CD8+ T cells pre-transplantation compared to patients staying CMV negative. Pre-transplant FoxP3+CD25+ in CD3+CD8+ T cells had the best discriminatory potential for CMV infection prediction within the first year after transplantation (AUC: 0.746). The FoxP3+CD25+ CD3+CD8+ T cell subset may aid in selecting intermediate risk kidney transplant recipients for CMV prophylaxis.

Low-Dose Valganciclovir Prophylaxis Against Cytomegalovirus in Intermediate-Risk Liver and Dual-Abdominal Transplant Recipients.

Low-dose valganciclovir (VGC) for cytomegalovirus (CMV) prophylaxis post-transplant has been employed due to cost and safety. The incidence of CMV disease in CMV intermediate-risk liver recipients at 1-year after standard-dose prophylaxis is approximately 5%. However, there are limited data on outcomes after using a "true" low-dose VGC prophylaxis regimen in liver and dual-abdominal transplant recipients as VGC was not dose-adjusted in all patients with impaired renal function in prior studies. The objective was to assess the incidence of CMV associated with low-dose VGC prophylaxis in CMV intermediate-risk liver, simultaneous pancreas-kidney (SPK), and simultaneous liver-kidney (SLK) recipients with creatinine clearance (CrCl) >60 mL/min. This was a retrospective review of CMV intermediate-risk liver, SPK, and SLK recipients with CrCl >60 mL/min transplanted January 2018 to June 2022 who received VGC 450 mg daily for prophylaxis. The primary outcome was incidence of CMV infection 6-months post-transplant. Ninety-nine transplant recipients were included (79 liver, 11 SPK, 9 SLK). The primary outcome occurred in 13% of patients (liver 10%, SPK 36%, SLK 10%), including 1 case of CMV disease and 3 breakthrough infections. In addition, 6 patients experienced CMV infection between 6-months and 1-year. Recurrence occurred in 3 patients. There was no evidence of CMV resistance. Thirty patients experienced neutropenia within 1-year, 32 were prescribed granulocyte-colony stimulating factors, and 5 experienced thrombocytopenia. Two patients died due to graft-vs-host disease. Low-dose VGC prophylaxis led to comparable CMV infection rates at 6-months in CMV intermediate-risk liver and SLK recipients. However, as SPK recipients displayed higher rates of CMV infection, low-dose VGC should be avoided in this population.

Evaluating the efficacy and safety of letermovir compared to valganciclovir for the prevention of human cytomegalovirus disease in adult lung transplant recipients.

Lung transplant recipients are at high risk for severe cytomegalovirus (CMV) disease. Off-label use of letermovir (LET) may avert myelotoxicity associated with valganciclovir (VGCV), but data in lung transplantation are limited. This study aims to evaluate the outcomes of LET prophylaxis among lung transplant recipients. This retrospective, matched cohort study included lung transplant recipients who received LET for primary CMV prophylaxis following VGCV intolerance. Patients were matched 1:1 to historical VGCV controls based on age, serostatus group, and time from transplant. The primary outcome was CMV breakthrough within 1 year post-LET initiation; secondary outcomes included hematologic changes. A total of 124 lung transplant recipients were included per group (32% CMV mismatch, D+R-), with LET initiated a median of 9.6 months post-transplantation. One CMV breakthrough event (0.8%) was observed in the LET group versus four (3.2%) in the VGCV group (p=.370). The median (interquartile range) white blood cell (WBC) count was3.1 (2.1-5.6)at LET initiation which increased to5.1 (3.9-7.2)at the end of follow-up (p <.001). For VGCV controls, WBC was4.8 (3.4-7.2)at baseline and5.4 (3.6-7.2)at the end of follow-up; this difference was not statistically significant (p=.395). Additionally, 98.4% of LET patients experienced ≥1 leukopenia episode in the year prior to LET compared to 71.8% the year after initiation (p <.001). Similar results were observed for neutropenia (48.4% and 17.7%, p <.001). LET prophylaxis was associated with a low rate of CMV reactivation and leukopenia recovery. LET may represent a reasonable prophylaxis option for lung transplant recipients unable to tolerate VGCV.

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

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. 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. 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). 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.