Letermovir prophylaxis is effective in preventing cytomegalovirus reactivation after allogeneic hematopoietic cell transplantation: single-center real-world data

Predictors of cytomegalovirus reactivation after allogeneic hematopoietic cell transplantation: Insights from a real-world experience

BACKGROUND

We aimed to investigate factors associated with cytomegalovirus (CMV) viremia and CMV disease and its impact on post-transplant outcomes including overall survival (OS) following allogeneic hematopoietic stem cell transplantation (Allo-SCT).

METHODS

We conducted a single-center retrospective study including 452 Allo-SCT recipients (matched unrelated donor, MUD 61%; haploidentical, haplo 39%) from 2016 to 2021. Data were analyzed using SPSS v28. Descriptive (chi-square and t-test), Kaplan-Meier and regression analyses were conducted.

RESULTS

The median age was 57 years. Sixty-one percent were males and 84.3% were Caucasians. CMV serostatus was positive in 59.1% of recipients. The median follow-up was 24.4 months. CMV viremia and CMV disease were observed in 181 (40%) and 32 (7%) patients, respectively. Among CMV seropositive recipients, 65% developed CMV viremia and 11% were noted to have CMV disease compared to 4% and 1% in seronegative recipients, respectively (p < 0.001). Patients with CMV disease had significantly lower OS than those without CMV disease (median 14.1 months vs. not reached, p = 0.024); however, OS was not associated with CMV viremia (median not reached in both groups, p = 0.640). Letermovir prophylaxis was used in 66% (n = 176/267) of CMV seropositive recipients, but no impact was observed on the incidence of CMV viremia or CMV disease and OS.

CONCLUSIONS

CMV disease leads to significantly inferior survival after an allogeneic hematopoietic cell transplantation. Recipient CMV seropositive status was associated with the risk of CMV viremia and CMV disease, and this was not abrogated with the use of Letermovir prophylaxis.

Cytomegalovirus Viral Load Threshold to Guide Preemptive Therapy in Hematopoietic Cell Transplant Recipients: Correlation With Cytomegalovirus Disease

A systematic review of randomized and observational studies from 2013 to 2023 demonstrated that antiviral preemptive therapy started at cytomegalovirus viral load thresholds between 2 and 3 log10 IU/mL was associated with similar cytomegalovirus disease rates. Thus, viral thresholds in this range appear to effectively protect patients not receiving prophylaxis.

Letermovir for cytomegalovirus infection in allogeneic hematopoietic stem-cell transplantation: tips and notes for effective use in clinical practice

INTRODUCTION

Cytomegalovirus (CMV) infection remains a major complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). While conventional antiviral agents such as ganciclovir can be used for CMV prophylaxis, toxicities such as myelosuppression are a major concern.

AREA COVERED

This work aimed to summarize the latest information and practical issues regarding a new anti-CMV agent, letermovir (LET).

EXPERT OPINION

LET inhibits CMV replication by binding to components of the DNA terminase complex. A phase 3 trial in allo-HSCT recipients showed a reduced incidence of clinically significant CMV infection in the LET group. In 2017, this agent was first approved for CMV prophylaxis in adult CMV-seropositive allo-HSCT recipients in the United States, and is now used worldwide. While LET has an excellent toxicity profile, there are issues to be aware of, such as interactions with other drug classes (e.g. immunosuppressants and antifungals) and reactivation of CMV infection following LET cessation. While LET is the current standard of care for CMV prophylaxis, there are no established protocols for preemptive treatment of asymptomatic CMV viremia or for treatment of developed CMV disease. Further research is needed to maximize the benefits of LET, including the discovery of biomarkers.

Letermovir for Cytomegalovirus infection in pediatric patients undergoing allogenic hematopoietic stem cell transplantation: a real-life study by the Infectious Diseases Working Group of Italian Association of Pediatric Hematology-Oncology (AIEOP)

Letermovir prophylaxis revolutionized the approach to Cytomegalovirus infection in adult hematopoietic stem cell transplant (HCT), while data in pediatric setting are still lacking. We retrospectively analyzed 87 HCT children transplanted in 11 AIEOP centers receiving letermovir as off-label indication between January 2020 and November 2022. Letermovir was used as primary, secondary prophylaxis or CMV treatment in 39, 26 and 22 cases, respectively; no discontinuation due to toxicity was reported. Median duration was 100 days (14-256) for primary and 96 days (8-271) for secondary prophylaxis, respectively. None of the patients experienced CMV-clinically significant reactivation during Letermovir primary prophylaxis; one patient developed breakthrough infection during secondary prophylaxis, and 10 and 1 patient experienced asymptomatic CMV-reactivation and CMV-primary infection after drug discontinuation, respectively. Median duration of letermovir in CMV treatment was 40 days (7-134), with 4/22 patients suffering CMV-pneumonia, with an overall response rate of 86.4%. With a median follow-up of 10.7 months (8.2-11.8), estimated 1-year overall survival was 86%; no CMV-related deaths were reported in prophylaxis groups. This is the largest report on Letermovir use in pediatric HCT; real-life data confirm an excellent toxicity profile, with high efficacy as CMV prophylaxis; results in CMV-infection treatment should be investigated in larger, prospective trials.

Real-Life Data on the Efficacy and Safety of Letermovir for Primary Prophylaxis of Cytomegalovirus in Allogeneic Hematopoietic Stem Cell Recipients: A Single-Center Analysis

Objective

Cytomegalovirus (CMV) reactivation is a life-threatening complication after allogeneic hematopoietic stem cell transplantation (HSCT). Introduction of letermovir (LMV) seems to improve post-transplant outcomes, but delayed-onset CMV reactivation still remains a challenge. In this study, we report on our first experience with LMV prophylaxis in 93 CMV-seropositive adult patients receiving HSCT in our center.

Materials and Methods

We retrospectively analyzed the data of 93 adult CMV-seropositive recipients receiving LMV as CMV prophylaxis after HSCT for hematological malignancies between 2019 and 2023. The starting LMV dose was 480 mg daily, reduced to 240 mg daily for those receiving cyclosporin A co-administration. CMV DNA in the blood was measured by real-time polymerase chain reaction weekly for the first 2 months after transplantation, then every other week until the end of immunosuppressive treatment. LMV was continued to day +100 or to CMV reactivation.

Results

The median recipient age at the time of transplant was 51 (range: 20-71) years. All patients received grafts from peripheral blood, mostly for acute myeloid leukemia (60%). The median time from transplantation to LMV initiation was 3 (range: 0-24) days. While 55% of patients were transplanted from matched related donors, 32% had unrelated donors and 13% underwent haploidentical HSCT. Four patients (4%) had CMV “blips” while on LMV, but the drug was continued and repeated assays were negative. Only 2 patients (2%) experienced CMV reactivation while on LMV, on days 48 and 34 after HSCT, respectively. Seven patients (7%) developed late-onset CMV reactivation after a median of 124 days after HSCT (range: 118-152 days) and they were successfully treated with ganciclovir. CMV disease was not observed. Grade III-IV acute graft-versus-host disease occurred in 6 patients (6%) during LMV treatment. LMV treatment was free of side effects.

Conclusion

LMV prophylaxis was effective in preventing CMV reactivation with a favorable safety profile. CMV reactivation occurred mostly after LMV discontinuation; thus, extending the duration of prophylaxis beyond 100 days could be beneficial.

Letermovir prophylaxis for cytomegalovirus reactivation in allogeneic hematopoietic cell transplant recipients: Single center Canadian data

BACKGROUND

Cytomegalovirus (CMV) is associated with morbidity and mortality following allogeneic hematopoietic cell transplantation (alloHCT). Letermovir is a novel antiviral agent that prevents CMV reactivation in alloHCT patients, with limited data regarding influence on post-alloHCT outcomes.

METHODS

We retrospectively examined 273 alloHCT recipients, 158 in the non-letermovir cohort (NLC), and 115 in the cohort using letermovir prophylaxis (LC). Patients that received letermovir were CMV-seropositive and met criteria for high risk of CMV reactivation.

RESULTS

Median start of letermovir was 21 days post-alloHCT, median duration of prophylaxis was 86 days. Letermovir prophylaxis demonstrated a statistically significant reduction in first CMV reactivation (at 200 days post 63.9% in the NLC vs. 35.7% in the LC; p < .001). On univariate analysis at 1 year, overall survival (OS) for NLC was 79.6% and 79.5% for LC (p = .54). Non relapse mortality (NRM) at 1 year for NLC was 12% and 12.3% for LC (p = .69). Cumulative incidence of relapse (CIR) at 1 year was 13.9% for NLC versus 17.1 for the LC (p = .27). On multivariable analysis, there was no significant difference between the two cohorts for OS, NRM, and CIR.

CONCLUSIONS

Letermovir prophylaxis started at day +21 post-alloHCT reduced CMV reactivation, with no impact on posttransplant outcomes.

Letermovir Effectively Prevents Cytomegalovirus Infection in Patients with Aplastic Anemia After Hematopoietic Stem Cell Transplantation: A Real-World Retrospective Cohort Study

INTRODUCTION

In this single-center retrospective cohort study, we investigated the efficacy of letermovir in preventing Cytomegalovirus (CMV) infection in patients with aplastic anemia (AA) who have undergone allogeneic hematopoietic stem cell transplantation (allo-HSCT).

METHODS

Based on whether or not letermovir was used for preventing CMV infection, the patients were categorized into two groups: letermovir and control groups. The overall survival (OS) rate and cumulative incidence of CMV infection during the first 100 days after allo-HSCT were evaluated. The study included 21 matched pairs of patients, identified through propensity score matching analysis, to compare CMV infection rates, treatment efficacy, and regression.

RESULTS

The incidence of CMV infection within 100 days after transplantation was significantly lower in the letermovir group than in the control group (26.5 vs. 77.4%, respectively; P < 0.001), among a total of 87 patients who underwent the transplant. In the matched cohort of 21 patients with AA, the letermovir group also showed a significantly reduced cumulative incidence of CMV infection (14.3 vs. 90.5% in the control group; P < 0.001). Compared to the control group, patients with CMV infection in the letermovir group had lower CMV-DNA load and a shorter clearance time. However, there was no significant difference in OS between both groups (P = 0.34).

CONCLUSIONS

Letermovir effectively prevents CMV infection in allo-HSCT recipients with AA and demonstrates a high safety profile.

Efficacy and safety of letermovir prophylaxis for cytomegalovirus infection after hematopoietic stem cell transplantation

Letermovir is a specific inhibitor of cytomegalovirus (CMV) terminase complex. Several studies have reported that letermovir can effectively prevent CMV activation after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We aimed to identify the efficacy and safety of letermovir prophylaxis for CMV infection after allo-HSCT with a systemic review and meta-analysis. A literature search was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. PubMed and Embase databases were searched. A total of 28 studies were included. The incidence of CMV activation at 14 weeks after HSCT was 0.10 (95% confidence interval [CI], 0.06-0.18), which was 0.10 (95% CI, 0.04-0.21) and 0% in adult and children (2 studies were included and both of them were 0%). In addition, the incidence of CMV activation at 14 weeks after allo-HSCT was 0.11 (95% CI, 0.06-0.21) and 0.07 (only 1 study included), respectively, in retrospective and prospective studies. The incidence of CMV activation at 100 and 200 days after HSCT was 0.23 (95% CI, 0.16-0.33) and 0.49 (95% CI, 0.32-0.67), respectively. The incidence of CMV disease at 14 weeks and at 6 months after HSCT was 0.01 (95% CI, 0.01-0.02) and 0.03 (95% CI, 0.01-0.09), respectively. Thus, our systemic review and meta-analysis suggested that letermovir prophylaxis was safe and effective for CMV activation after allo-HSCT.

Outcomes of allogeneic hematopoietic cell transplantation under letermovir prophylaxis for cytomegalovirus infection

Cytomegalovirus (CMV) infection is a major infectious complication following allogeneic hematopoietic cell transplantation (allo-HCT). Although letermovir (LMV) prophylaxis dramatically reduces the incidence of early clinically significant CMV (csCMV) infection, it remains unclear whether it has a beneficial effect on nonrelapse mortality (NRM) and overall survival (OS). Herein, we evaluated the impact of LMV prophylaxis on posttransplant outcomes using the registry database of the Japanese Society for Transplantation and Cellular Therapy. Adult patients who underwent allo-HCT between 2017 and 2019 were analyzed (n = 6004). LMV prophylaxis was administered to 1640 patients (LMV group) and it significantly reduced the incidence of csCMV infection compared with those not administered LMV prophylaxis (15.4% vs 54.1%; p < 0.01). However, it did not improve the 1-year NRM (hazard ratio [HR], 0.93; p = 0.40) and OS (HR, 0.96; p = 0.49). In the LMV group, 74 patients had breakthrough csCMV infection and showed inferior NRM (HR, 3.44; p < 0.01) and OS (HR, 1.93; p = 0.02) compared with those without infection. After completing LMV prophylaxis, 252 patients had late csCMV infection and showed inferior NRM (HR, 1.83; p < 0.01) and OS (HR, 1.58; p < 0.01). Our findings suggest that managing breakthrough and late csCMV infections is important for improving long-term outcomes.

Refractory cytomegalovirus infections in Chinese patients receiving allogeneic hematopoietic cell transplantation: a review of the literature

In the absence of prophylactic therapy, cytomegalovirus (CMV) viremia is a common complication following allogeneic hematopoietic cell transplantation (allo-HCT) and represents a significant cause of morbidity and mortality. Approximately 25% of allo-HCT happen in China, where the development and refinement of the 'Beijing protocol' has enabled frequent and increasing use of haploidentical donors. However, refractory CMV infection (an increase by >1 log10 in blood or serum CMV DNA levels after at least 2 weeks of an appropriately dosed anti-CMV medication) is more common among patients with haploidentical donors than with other donor types and has no established standard of care. Here, we review the literature regarding refractory CMV infection following allo-HCT in China.

Extended duration letermovir in allogeneic hematopoietic stem cell transplant

OBJECTIVES

Despite the use of antiviral prophylaxis in recipients of allogeneic hematopoietic cell transplants (HCT), cytomegalovirus (CMV) is a common clinically significant infection and is associated with significant morbidity and mortality in this patient population. Based on current approval, letermovir is initiated within 28 days following allogeneic HCT for CMV seropositive recipients and continued through 100 days post-transplant. However, it is unknown whether patients who receive extended duration CMV prophylaxis with letermovir would result in less CMV reactivation and reactivation compared to those who do not. This study aimed to evaluate the efficacy of letermovir prophylaxis in CMV seropositive patients when continued for greater than 100 days post-allogeneic stem cell transplant.

METHODS

A single-center retrospective chart review was conducted on recipients of allogeneic HCT from November 2017 to July 2021. Patients were eligible for inclusion if they were at least 18 years of age, received an allogeneic HCT, CMV seropositive, and initiated letermovir between days 0-28 post-transplant. The primary endpoint of this study is to compare rates of CMV reactivation in patients who stopped letermovir prophylaxis at 100 days post-transplant (standard duration group) versus those who continued letermovir prophylaxis past day 100 (extended duration group).

RESULTS

A total of 87 patients met the eligibility criteria for inclusion. The median duration of letermovir prophylaxis was 78 days in the standard duration group versus and 132 days in the extended duration group. There were more CMV reactivations in the standard duration group versus the extended duration group, 28% versus 19% respectively. CMV pneumonitis was observed in one of the patients in the standard duration group. All-cause mortality at day 200 post-transplant was similar between the two groups.

CONCLUSION

The results of this study suggest that extended duration letermovir prophylaxis may be associated with less CMV reactivation compared to the standard duration of prophylaxis.

Cytomegalovirus reactivation under pre-emptive therapy following allogeneic hematopoietic stem cell transplant: Pattern, survival, and risk factors in the Republic of Korea

INTRODUCTION

Pre-emptive therapy for cytomegalovirus (CMV) reactivation has been used in allogeneic hematopoietic stem cell transplantation (allo-HSCT). It is unclear if this strategy has poorer clinical outcomes in CMV-endemic areas and if more aggressive prophylaxis is required.

METHODS

We retrospectively analyzed the patterns and survival after CMV reactivation in patients undergoing pre-emptive therapy following allo-HSCT and assessed high-risk patients who could benefit from aggressive CMV prophylaxis in endemic areas.

RESULTS

Of the 292 patients who underwent allo-HSCT, 70.5% (donor+ or recipient+) were CMV seropositive. CMV reactivation occurred in 139 patients (47.6%), with a median of 31.5 days from day 0 of allo-HSCT. The overall survival of patients with CMV reactivation who received pre-emptive therapy did not differ from those without reactivation. Of the 139 patients with CMV reactivation, 78 (56.1%) underwent ≥2 rounds of pre-emptive therapy. In multivariate analysis, the risk of CMV reactivation was higher in patients with multiple myeloma, with CMV seropositivity of the recipient and donor, administered with a higher dose of anti-thymocyte globulin (ATG), and with acute graft-versus-host disease (aGVHD) ≥ grade 2.

CONCLUSION

Although half of the patients with allo-HSCT were administered with pre-emptive therapy for CMV, CMV reactivation did not affect their survival, indicating the advantages of pre-emptive therapy, even in CMV-endemic areas. The cost-effectiveness of more aggressive CMV prophylaxis should be re-evaluated in patients at a high risk for CMV reactivation.

Efficacy of letermovir in HLA-haploidentical hematopoietic transplantation with posttransplant cyclophosphamide

BACKGROUND

Cytomegalovirus reactivation (CMV-R) is a significant complication of allogeneic hematopoietic stem cell transplantation (allo-HCT), especially in human leukocyte antigen-haploidentical transplantation (haplo-HCT) with posttransplant cyclophosphamide (PTCy). Prophylactic letermovir (LTV) prevents CMV-R in patients undergoing allo-HCT. However, evidence regarding its use in haplo-HCTs with PTCy is limited. Therefore, we aimed to investigate the efficacy of prophylactic LTV in haplo-HCT with PTCy.

METHODS

We retrospectively analyzed 52 patients seropositive for CMV who underwent haplo-HCT with PTCy at our institution between January 2015 and June 2021 and compared patients who received LTV prophylaxis (LTV group: n = 29) with those who did not receive prophylaxis for CMV (control group: n = 23). The primary endpoint was the 100-day cumulative CMV-R incidence. We used Gray's test and the Fine and Gray test to compare the two groups.

RESULTS

The 100-day cumulative CMV-R incidence was lower in the LTV group than in the control group (17.2% vs 81.8%, p < 0.001). Multivariate analysis revealed that prophylactic LTV reduced the 100-day cumulative CMV-R incidence (hazard ratio: 0.17, 95% confidence interval: 0.06-0.44, p < 0.001).

CONCLUSIONS

Prophylactic LTV effectively prevents CMV-R in patients undergoing haplo-HCT for PTCy.

Effectiveness of letermovir for cytomegalovirus prophylaxis in allogeneic hematopoietic stem cell transplant recipients: A global systematic review

OBJECTIVE(S)

Letermovir (LET), a novel antiviral, has largely supplanted more traditional preemptive therapy (PET) for cytomegalovirus (CMV) prophylaxis in allogeneic hematopoietic stem cell transplant (allo-HCT) patients. Use of LET demonstrated efficacy against placebo in phase III randomized controlled trials, but is considerably more expensive than PET. This review aimed to evaluate the real-world effectiveness of LET in preventing clinically significant CMV infection (csCMVi) for allo-HCT recipients and related outcomes.

DESIGN

A systematic literature review was performed using an a priori protocol using PubMed, Scopus, and ClinicalTrials.gov from January 2010 to October 2021.

SETTING AND PARTICIPANTS

Studies were included if they met the following criteria: LET compared with PET, CMV-related outcomes, patients aged 18 years or older, and English language-only articles. Descriptive statistics were used to summarize study characteristics and outcomes.

OUTCOME MEASURES

CMV viremia, csCMVi, CMV end-organ disease, graft-versus-host-disease, all-cause mortality.

RESULTS

A total of 233 abstracts were screened, with 30 included in this review. Randomized trials demonstrated efficacy of LET prophylaxis in preventing csCMVi. Observational studies demonstrated varying degrees of effectiveness of LET prophylaxis compared with use of PET alone. All studies with a comparator group resulted in lower rates of csCMVi for patients using LET. Included studies varied widely by CMV viral load threshold cutoff and CMV test units, limiting synthesis of results owing to high heterogeneity.

CONCLUSION

LET reduces risk of csCMVi, but lack of standardized clinical definitions on how to evaluate csCMVi and related outcomes largely prevent synthesis of results. Clinicians must consider this limitation in the context of evaluating the effectiveness of LET to other antiviral therapies, especially for patients at risk of late-onset CMV. Future studies should focus on prospective data collection through registries and concordance of diagnostic definitions to mitigate study heterogeneity.

Cytomegalovirus in children undergoing haematopoietic stem cell transplantation: a diagnostic and therapeutic approach to antiviral resistance

Cytomegalovirus (CMV) is a ubiquitous virus which causes a mild illness in healthy individuals. In immunocompromised individuals, such as children receiving haematopoietic stem cell transplantation, CMV can reactivate, causing serious disease and increasing the risk of death. CMV can be effectively treated with antiviral drugs, but antiviral resistance is an increasingly common complication. Available therapies are associated with adverse effects such as bone marrow suppression and renal impairment, making the choice of appropriate treatment challenging. New agents are emerging and require evaluation in children to establish their role. This review will discuss established and emerging diagnostic tools and treatment options for CMV, including antiviral resistant CMV, in children undergoing haematopoietic stem cell transplant.

Real world experience: Examining outcomes using letermovir for CMV prophylaxis in high-risk allogeneic hematopoietic stem cell patients in the setting of using T-cell depletion as GVHD prophylaxis

BACKGROUND

Cytomegalovirus (CMV) infection significantly impacts the morbidity and mortality of patients undergoing allogeneic hematopoietic stem cell transplant (HSCT). Despite monitoring and pharmacologic prophylaxis with drugs such as valganciclovir or ganciclovir, rates of early CMV reactivation have continually persisted, contributing to increased rates of morbidity and mortality in allogeneic-HSCT patients. This study evaluates the outcomes of letermovir in preventing CMV reactivation and CMV-related complications in HSCT recipients with initiation of therapy at +21 days in high-risk patients.

METHODS

We retrospectively analyzed adult patients at University of Southern California (USC) Norris Cancer Hospital who received allogeneic-HSCT from 2018 to 2020 with subsequent serial CMV monitoring and treatment. CMV reactivation was determined in patients if they had clinically significant serum CMV viremia (viremia requiring treatment) or organ involvement by day+100. Primary endpoint assessed was day+100 rates of CMV reactivation. Secondary end-points included 1-year OS, 1-year RFS, and incidence of GVHD. Descriptive statistics were used to compare characteristics between groups used in this study, with a significance level of α = 0.05.

RESULTS

Between 2018 and 2020, 116 adult HSCT recipients were reviewed. 51% were male and 49% were female; donor sources consisted of 27% match related donor (MRD) 28% match-unrelated donor (MUD), and 45% haploidentical donor. Of the 116 patients, 92 were identified as high-risk for CMV reactivation. 71 patients received letermovir prophylaxis, and 21 patients received no prophylaxis. In high-risk patients, after adjusting for GVHD status and transplant type, patients that received letermovir had no statistically significant difference of having D + 100 CMV reactivation compared to patients that did not receive letermovir. 1.02 (95% CI: 0.35, 3.20) (p = 0.97). Moreover, there were no statistically significant difference observed between letermovir treatment and 1-year OS, 1-year RFS, and incidence of GVHD.

CONCLUSION

Patients in the high-risk letermovir group had outcomes that were comparable to the lower risk "non-letermovir" group. There was no significant difference in CMV D + 100 reactivation between high-risk patients who did not receive letermovir compared to the patients who did. While other studies have shown that early initiation of letermovir may be associated with improved outcomes, our study shows that the use of letermovir with initiation at 21 days may not necessarily translate to improved secondary outcomes such as overall survival. Further prospective studies evaluating the time of initiating therapy and outcomes are needed.

Cytomegalovirus Therapy: Role of Letermovir in Prophylaxis and Treatment in Transplant Recipients

Cytomegalovirus (CMV) is a common viral pathogen in the transplant population and is associated with significant morbidity and mortality. CMV prevention is paramount; however, selecting the best preventive strategy depends on many factors including donor-recipient CMV serostatus, transplant-specific risks, antiviral toxicities and cost. Novel CMV therapeutics such as letermovir (LTV) are desperately needed to optimize CMV management. Uniquely among CMV antiviral therapies, LTV inhibits the viral terminase complex in the CMV DNA synthesis pathway and disrupts viral genome packaging. Further, it lacks side effects frequently associated with other CMV antiviral therapies and evades common mechanisms of resistance. LTV is approved by the US Food and Drug Administration for CMV prevention in adult CMV-seropositive hematopoietic cell transplant recipients but is increasingly applied off-label for prophylaxis and treatment. This review summarizes important concepts of CMV management in transplantation, with a specific focus on LTV pharmacology and clinical experience to date alongside future prospects for its application.

Risk factor analysis for cytomegalovirus reactivation under prophylaxis with letermovir after allogeneic hematopoietic stem cell transplantation

BACKGROUND

Letermovir has been approved as a novel cytomegalovirus (CMV) prophylactic agent after allogeneic hematopoietic stem cell transplantation (HSCT). However, there are still insufficient data to properly evaluate the real-world role of letermovir, and the risk factors for CMV reactivation under letermovir prophylaxis have not been clarified.

METHODS

We performed a single-institution retrospective analysis of patients under prophylaxis with or without letermovir who underwent allogeneic HSCT between March 2012 and December 2019. In August 2018, letermovir was added to the clinical practice at our institution for the prophylaxis of CMV reactivation in allogeneic HSCT recipients. Patients who underwent HSCT without prophylactic letermovir from March 2012 until September 2018 served as a historical control.

RESULTS

The cumulative incidence of clinically significant CMV infection (CS-CMVi) was significantly lower in the letermovir group than in the historical control group not receiving letermovir (30.2% vs. 71.6%, p < .05, at 100 days). In addition, the cumulative incidence of non-relapse mortality (NRM) at day 500 was significantly lower in the letermovir group (4.7% vs. 19.8%, p < .05). We then performed a risk factor analysis for developing CS-CMVi in the letermovir group. The only significant factor identified by this multivariable analysis was transplantation from a CMV seronegative donor to a seropositive recipient (Hazard ratio = 2.76, 95% confidence interval 1.14-6.68, p < .05).

CONCLUSION

Our study showed that letermovir prophylaxis significantly reduced the incidence of CS-CMVi and NRM in a real-world setting and that the CMV serostatus of the donor remained as a risk factor for CS-CMVi even under letermovir prophylaxis.

Extended-duration letermovir prophylaxis for cytomegalovirus infection after cord blood transplantation in adults

Cord blood transplantation (CBT) can be complicated by a high incidence of clinically significant cytomegalovirus infection (csCMVi). We have investigated the efficacy of extended letermovir prophylaxis in seropositive adult CBT recipients. The aim was to continue prophylaxis for ≥6 months (insurance permitting). By day 100, the incidence of csCMVi was 0% in 28 patients who received letermovir prophylaxis. Moreover, of 24 patients alive at day 100, none had csCMVi by day 180, having continued prophylaxis for all (n = 20) or part (n = 4) of that period. Overall, 20 patients stopped letermovir at a median of 354 days (range, 119-455 days) posttransplant, with only 5 requiring 1 (n = 4) or 2 (n = 1) courses of valganciclovir (median total duration, 58 days; range, 12-67 days) for postprophylaxis viremia, with no subsequent csCMVi. There were no toxicities attributable to letermovir. Of the 62 historic control subjects who received acyclovir only, 51 developed csCMVi (median onset, 34 days; range, 5-74 days), for a day 100 incidence of 82% (95% confidence interval, 73-92). Seven patients developed proven/probable CMV disease, and 6 died before day 100 (3 with proven/probable CMV pneumonia). Forty-five patients required extended therapy during the first 6 months for 1 (n = 10), 2 (n = 14), or 3/persistent (n = 21) csCMVi, with 43 (84%) of 51 developing significant treatment toxicities. Letermovir is a highly effective, well-tolerated prophylaxis that mitigates CMV infection, CMV-related mortality, and antiviral therapy toxicities in CBT recipients. Our data support prophylaxis duration of at least 6 months after CBT.

Real-world efficacy of letermovir prophylaxis for cytomegalovirus infection after allogeneic hematopoietic stem cell transplantation: A single-center retrospective analysis

INTRODUCTION

Cytomegalovirus (CMV) infection is a common complication following allogeneic hematopoietic stem cell transplantation (aHSCT) and is associated with increased mortality. Letermovir (LET) is a novel antiviral drug used to prevent CMV infection.

METHODS

We analyzed 111 consecutive patients who underwent aHSCT, retrospectively, to evaluate the efficacy of LET prophylaxis for clinically significant CMV infection (csCMVi) in real-world situations. In addition, we analyzed the influence of LET on transplant outcomes. Thirty-eight patients who were administered LET prophylactically were compared with 73 patients without LET prophylaxis after aHSCT.

RESULTS

On day 180, the cumulative incidence of csCMVi in patients who received LET prophylaxis was significantly lower than that in patients without LET prophylaxis (29.7% vs. 56.2%, P < 0.001). Among the patients who developed csCMVi, the interval from aHSCT to the initiation of preemptive therapy was significantly longer in patients who received LET prophylaxis than in those who did not (129.5 days vs. 42 days, P < 0.001). The six-month overall survival was 86.1% in patients who received LET prophylaxis and 66.8% in the non-LET group (P = 0.035).

CONCLUSION

LET prophylaxis was highly effective in preventing csCMVi and could potentially improve transplant outcomes, particularly when initiated early after transplantations.

Cytomegalovirus infection and rehospitalization rates after allogeneic hematopoietic stem cell and solid organ transplantation: a retrospective cohort study using German claims data

PURPOSE

This study aimed to describe the cytomegalovirus (CMV) infection rate, rehospitalizations, and comorbidities following allogeneic hematopoietic stem cell transplantation (allo-HSCT) and solid organ transplantation (SOT).

METHODS

Patients who received allo-HSCT or SOT in 01/07/2015-30/06/2018 were identified using anonymized German claims data. The transplantation-related hospital admission date was defined as the index date, and patients were followed for up to 12 months (or death, first event relevant). The frequency of CMV infections (confirmed outpatient/inpatient diagnoses, ICD-10-GM codes: B25.-/B27.1) and the rate, number, and duration of all-cause rehospitalizations in the follow-up period were evaluated.

RESULTS

A total of 226 allo-HSCT and 250 SOT patients were identified (mean age 52.8 years, 38.9% female). During the 12 months after transplantation, 29.2% of allo-HSCT patients and 16.8% of SOT patients received a CMV diagnosis. The majority of these diagnoses were given during the initial hospitalization or within the following 3 months. Across transplantation types, CMV patients had more hospital readmission days per patient-year (allo-HSCT 93.3 vs. 49.4, p = 0.001; SOT 42.0 vs. 20.7, p = 0.005), with a longer mean duration of readmissions (allo-HSCT 22.4 vs. 15.4 days, p < 0.001; SOT 11.6 vs. 7.5 days, p = 0.003). Comorbidity burden in transplantation patients was substantial, with several diagnoses being significantly more common among patients with CMV vs. non-CMV. One-year mortality did not differ significantly between patients with/without CMV.

CONCLUSION

Burden of transplant recipients with CMV in terms of rehospitalizations and comorbidities is substantial, highlighting the need for improved CMV prevention and treatment.

Risk factors for late cytomegalovirus infection after completing letermovir prophylaxis

Prophylactic use of letermovir (LMV) markedly reduces the incidence of early clinically significant cytomegalovirus (csCMV) infection within the first 100 days after allogeneic hematopoietic cell transplantation (allo-HCT), which improves transplant outcomes. However, some patients eventually develop late-csCMV infection (beyond day 100) after completing LMV prophylaxis. To assess the incidence of late-csCMV infection as well as its risk factors and impacts on transplant outcome, a total of 81 allo-HCT recipients who had not developed early csCMV infection during LMV prophylaxis were retrospectively analyzed. Among them, 23 (28.4%) patients developed late-csCMV infection (until day 180) at a median time of 131 days after transplantation and 30 days after LMV discontinuation, respectively. Late-csCMV infection was correlated with apparent delayed immune reconstitution: patients transplanted from HLA-mismatched donors (hazard ratio [HR] = 13.0, p = 0.011) or CMV-IgG-negative donors (HR = 2.39, p = 0.043) had a significantly higher risk. In this study, transplant outcomes did not differ between patients with and without late-csCMV infection. This suggests a need to clarify the efficacy of extended administration of LMV for preventing late-csCMV infection in a larger number of allo-HCT recipients, especially those with "high-risk" donors.

Safety and Effectiveness of Letermovir in Allogenic Hematopoietic Stem Cell Transplantation Recipients: Interim Report of Post-marketing Surveillance in Japan

OBJECTIVE

Since May 2018, a 6-year post‑marketing surveillance (PMS) has been underway to evaluate the safety and effectiveness of letermovir for cytomegalovirus (CMV) prophylaxis in Japanese patients with allogenic hematopoietic stem-cell transplantation (allo-HSCT). The interim PMS data for 461 patients collected as of March 2021 are reported in this publication.

METHODS

The case report forms (CRFs) were drafted in part by the Japanese Data Center for Hematopoietic Cell Transplantation (JDCHCT) using data elements in the Transplant Registry Unified Management Program (TRUMP) and sent to individual HSCT centers to decrease burden of reporting. These CRFs were completed by physicians in the respective HSCT centers and sent to MSD K.K., Tokyo, Japan.

RESULTS

Allo-HSCT recipients prescribed with letermovir for CMV prophylaxis were included across 136 centers in Japan between May 2018 and March 2021. Safety and effectiveness were assessed for 460 and 373 patients, respectively. Of the patients in the safety analysis, 13.9 % experienced adverse drug reactions, the most frequent of which were renal impairment (2.2 %) and nausea (1.7 %). Among patients in the effectiveness analysis, the overall CMV antigen positivity rate was 21.2 % at Week 14 and 37.5 % at Week 24 after allo-HSCT.

CONCLUSIONS

Interim data from this largest of real-world studies confirm the safety and effectiveness of letermovir for CMV prophylaxis in Japanese allo-HSCT recipients. Given the limited data on Asian patients for letermovir use, this survey will provide valuable information for medical decision-making in routine clinical practice, serving as a vital supplement to the results obtained from clinical trials.

Letermovir Prophylaxis for Cytomegalovirus Infection in Allogeneic Stem Cell Transplantation: A Real-World Experience

Despite effective treatments, cytomegalovirus (CMV) continues to have a significant impact on morbidity and mortality in allogeneic stem cell transplant (allo-SCT) recipients. This multicenter, retrospective, cohort study aimed to evaluate the reproducibility of the safety and efficacy of commercially available letermovir for CMV prophylaxis in a real-world setting. Endpoints were rates of clinically significant CMV infection (CSCI), defined as CMV disease or CMV viremia reactivation within day +100-+168. 204 adult CMV-seropositive allo-SCT recipients from 17 Italian centres (median age 52 years) were treated with LET 240 mg/day between day 0 and day +28. Overall, 28.9% of patients underwent a haploidentical, 32.4% a matched related, and 27.5% a matched unrelated donor (MUD) transplant. 65.7% were considered at high risk of CSCI and 65.2% had a CMV seropositive donor. Low to mild severe adverse events were observed in 40.7% of patients during treatment [gastrointestinal toxicity (36.3%) and skin rash (10.3%)]. Cumulative incidence of CSCI at day +100 and day +168 was 5.4% and 18.1%, respectively, whereas the Kaplan-Meier event rate was 5.8% (95% CI: 2.4-9.1) and 23.3% (95% CI: 16.3-29.7), respectively. Overall mortality was 6.4% at day +100 and 7.3% at day +168. This real-world experience confirms the efficacy and safety of CMV.

American Society for Transplantation and Cellular Therapy Series: #3-Prevention of Cytomegalovirus Infection and Disease After Hematopoietic Cell Transplantation

The Practice Guidelines Committee of the American Society for Transplantation and Cellular Therapy partnered with its Transplant Infectious Disease Special Interest Group to update its 2009 compendium-style infectious diseases guidelines for the care of hematopoietic cell transplant (HCT) recipients. A new approach was taken with the goal of better serving clinical providers by publishing each standalone topic in the infectious disease series as a concise format of frequently asked questions (FAQ), tables, and figures. Adult and pediatric infectious disease and HCT content experts developed and answered FAQs. Topics were finalized with harmonized recommendations that were made by assigning an A through E strength of recommendation paired with a level of supporting evidence graded I through III. The third topic in the series focuses on the prevention of cytomegalovirus infection and disease in HCT recipients by reviewing prophylaxis and preemptive therapy approaches; key definitions, relevant risk factors, and diagnostic monitoring considerations are also reviewed.