Prevymis (letermovir) / Merck (MSD), AiCuris, Veloxis, Asahi Kasei Therapeutics - LARVOL DELTA

Open Label Trial of Oral Letermovir for CMV Prophylaxis in Thoracic Transplant Recipients (clinicaltrials.gov) - P2 | N=80 | Active, not recruiting | Sponsor: University of Pennsylvania | Recruiting ➔ Active, not recruiting | Trial completion date: Aug 2026 ➔ Jan 2027 | Trial primary completion date: Aug 2026 ➔ Dec 2026

Enrollment closed • Trial completion date • Trial primary completion date • Cytomegalovirus Infection • Infectious Disease • Neutropenia • Transplantation

De-novo Initiation of Letermovir vs Valganciclovir for Cytomegalovirus Prophylaxis in AA Kidney Transplant Recipients (clinicaltrials.gov) - P3 | N=30 | Completed | Sponsor: Virginia Commonwealth University | Active, not recruiting ➔ Completed

Trial completion • Cytomegalovirus Infection • Transplantation • CYP3A5

Extended letermovir prophylaxis for cytomegalovirus in intermediate-risk (R+) kidney transplant recipients: A pilot real-world cohort study (TTS 2026) - "While valganciclovir has been widely used for prophylaxis, its myelotoxicity and potential drug-related adverse events may limit long-term administration...Maintenance immunosuppression consisted of tacrolimus (Tac) plus everolimus (EVR) in 21 patients and Tac plus mycophenolate mofetil (MMF) in 2 patients...One patient experienced diarrhea attributed to tacrolimus, leading to temporary interruption of letermovir; after conversion from Tac to cyclosporine, letermovir was successfully resumed without further complications... In this pilot real-world cohort of CMV R+ kidney transplant recipients, letermovir prophylaxis initiated early after transplantation and continued for approximately 200 days was safe and effective. No CMV DNAemia or acute rejection episodes occurred during prophylaxis, and hematologic toxicity was absent. Our findings suggest that letermovir may represent a viable prophylactic strategy in intermediate-risk (R+) kidney transplant recipients,..."

Clinical • Real-world • Real-world evidence • Bone Marrow Transplantation • Cytomegalovirus Infection • Hematological Disorders • Infectious Disease • Leukopenia • Neutropenia • Transplant Rejection • Transplantation

Comment on "Impact of Acute Graft-Versus-Host Disease and Delayed Hematopoietic Recovery on the Incidence and Clinical Burden of Late Cytomegalovirus Reactivation and Disease after Letermovir Prophylaxis during the First 100 Days after Cord Blood Transplantation". (PubMed, Transplant Cell Ther) - No abstract available

Journal • Acute Graft versus Host Disease • Cytomegalovirus Infection • Graft versus Host Disease • Immunology • Infectious Disease • Transplantation

Risk Factors for Cytomegalovirus Infection after Allogeneic Hematopoietic Cell Transplantation Using Rabbit Anti-thymocyte Globulin or Porcine Anti-human T Lymphocyte Immunoglobulin in the Letermovir Era. (PubMed, Transplant Cell Ther) - "Despite LTV prophylaxis, csCMVi remains frequent in T-cell-depleted recipients. Acute GVHD is a key risk factor. Different anti-thymocyte globulin preparations are associated with distinct CMV risk profiles and early viral kinetics. These findings warrant further validation and investigation of their clinical implications in the LTV era."

Journal • Preclinical • Acute Graft versus Host Disease • Cytomegalovirus Infection • Graft versus Host Disease • Immunology • Infectious Disease • Transplantation

Letermovir for cytomegalovirus prophylaxis after allogeneic hematopoietic stem cell transplantation in acute leukemia patients: results of the LETreal study. (PubMed, Front Immunol) - "The incidence of cs-CMVi between 100 and 200 days after allo-HSCT was comparable between patients with prolonged letermovir prophylaxis and those without letermovir prophylaxis. We confirmed the efficacy of letermovir prophylaxis in different subgroups, but the subgroup who would benefit most from prolonged prophylaxis should be further clarified in the future."

Journal • Acute Graft versus Host Disease • Bone Marrow Transplantation • Chronic Graft versus Host Disease • Cytomegalovirus Infection • Graft versus Host Disease • Hematological Malignancies • Immunology • Infectious Disease • Leukemia • Oncology • Transplantation

Real-world CMV hyperimmunoglobulin prophylaxis in heart and lung transplantation: one-year interim results from a prospective multicenter study (TTS 2026) - "Antiviral exposure during follow-up included valganciclovir (79%), ganciclovir (30%), letermovir (6%), and maribavir (5%). In this prospective real-world HTx and LuTx cohort, adjunctive CMVIG prophylaxis was associated with low rates of treatment-requiring CMV, CMV syndrome, and tissue-invasive disease at one year, with low rates of CMVIG-related adverse events. Final results from the complete 553-patient cohort will further clarify the role of CMVIG across CMV management settings in HTx and LuTx."

Clinical • Real-world • Real-world evidence • Cytomegalovirus Infection • Infectious Disease • Transplantation

Real World use of Letermovir and Valganciclovir for CMV Prophylaxis (IDWeek 2026) - No abstract available

Clinical • Real-world • Real-world evidence • Infectious Disease

Budget Impact of Prophylactic Letermovir to Prevent Cytomegalovirus Disease in High-Risk Adult Kidney Transplant Recipients. (PubMed, Pharmacoecon Open) - "This analysis provides evidence on the potential impact of introducing letermovir into the US market. While the acquisition cost of letermovir is higher than that of VGCV, there are estimated cost savings, primarily driven by the prevention of LN events and their associated downstream clinical consequences, suggesting that the savings from LN avoidance outweigh the incremental prophylaxis costs of introducing letermovir. However, the overall budget impact remains minimal and should be interpreted in the context of the evolving evidence base."

HEOR • Journal • Cytomegalovirus Infection • Hematological Disorders • Infectious Disease • Leukopenia • Neutropenia • Transplant Rejection • Transplantation

Early Initiation of Letermovir Prophylaxis Prevents Cytomegalovirus Infection After Liver Transplantation: A Prospective Single-Center Study (TTS 2026) - "Treatment was discontinued in cases of adverse events, CMV antigenemia, or CMV disease, with conversion to ganciclovir or valganciclovir as appropriate. Early initiation of letermovir prophylaxis within 2 weeks after liver transplantation effectively prevents CMV infection and is a safe strategy. These findings highlight the critical importance of early prophylactic intervention in optimizing CMV prevention."

Clinical • Cytomegalovirus Infection • Hepatology • Infectious Disease • Transplantation

Reply: Letter to the Editor Regarding "Impact of Acute Graft-Versus-Host Disease and Delayed Hematopoietic Recovery on the Incidence and Clinical Burden of Late Cytomegalovirus Reactivation and Disease After Letermovir Prophylaxis During the First 100 Days After Cord Blood Transplantation". (PubMed, Transplant Cell Ther) - No abstract available

Journal • Acute Graft versus Host Disease • Cytomegalovirus Infection • Graft versus Host Disease • Immunology • Transplantation

Breakthrough Cytomegalovirus Viremia During Letermovir Prophylaxis After Allogeneic Hematopoietic Stem Cell Transplantation: A Systematic Review and Meta-analysis (IDWeek 2026) - No abstract available

Retrospective data • Review • Cytomegalovirus Infection • Infectious Disease

Utilization of Crushed Letermovir in Allogeneic Hematopoietic Cell Transplant and Cellular Therapies (IDWeek 2026) - No abstract available

Infectious Disease

Letermovir as Cytomegalovirus Prophylaxis Among Pediatric Solid Organ Transplant Recipients: A Multicenter Cross-Sectional Survey (IDWeek 2026) - No abstract available

Clinical • Cytomegalovirus Infection • Infectious Disease

The Heavy Hitters of Transplant ID (IDWeek 2026) - "Learning Objectives: At the conclusion of this session, participants will be able to:Analyze the epidemiologic exposure risks, timeline after transplantation (early, intermediate, late), and distinct clinical manifestations of major opportunistic pathogens in solid organ (SOT) and hematopoietic stem cell transplant (HSCT) recipients focusing on high-consequence viral (CMV, EBV, BK virus) and invasive fungal pathogens (Aspergillus, Mucorales)Evaluate modern diagnostic modalities for complex transplant-related infections, including quantitative viral PCR monitoring, resistance genotyping (e.g., UL97/UL54 mutations in refactory CMV), and non-invasive fungal biomarkers to guide timely clinical intervention.Develop patient-specific prevention and treatment plans that integrate novel antimicrobial agents (e.g., maribavir, letermovir, isavuconazole), adjust underlying immunosuppressive therapy to balance rejection risk against infection control, and apply preemptive management..."

Infectious Disease

ANZTCT cytomegalovirus practice survey for allogeneic haemopoietic stem cell transplant and cellular therapy recipients in Australia and New Zealand. (PubMed, Intern Med J) - "Institutional preferences and medicine funding drives variability in ANZ practice. This leaves potential for healthcare inequity since newer antiviral agents are inconsistently used, contrasting with international guidelines."

Journal • Bone Marrow Transplantation • Cytomegalovirus Infection • Infectious Disease • Pediatrics • Transplantation

SAFETY AND EFFICACY OF FLUDARABINE PLUS MYELOABLATIVE DOSE OF TREOSULFAN (FT14) CONDITIONING REGIMEN FOR AML – INTERIM ANALYSIS FROM THE FT14 STUDY GROUP (EBMT 2025) - "While busulfan-based regimens such as fludarabine-busulfan (FB4) are widely regarded as the gold standard for reduced-toxicity myeloablative conditioning, they are associated with risks such as Veno-Occlusive Disease (VOD), pulmonary toxicity, and high Transplant-Related Mortality (TRM)...Graft sources included peripheral blood stem cells or bone marrow, with Graft-versus-Host Disease (GvHD) prophylaxis using ATG (Thymoglobulin or Grafalon), cyclosporine and short course methotrexate...On viral point of view, 6% experienced CMV reactivation despite letermovir prophylaxis, 11% had detectable EBV viraemia (with no case of post-transplant lymphoproliferative disease), 4% had SARS-CoV-2 and 2% HHV6 reactivation... FT14 is a safe and effective myeloablative conditioning regimen for AML, demonstrating excellent disease control with minimal toxicity. Its reduced transplant-related mortality(TRM) and GvHD rates make it particularly beneficial for patients at high risk of..."

Clinical • Acute Graft versus Host Disease • Acute Myelogenous Leukemia • Bone Marrow Transplantation • Chronic Graft versus Host Disease • Graft versus Host Disease • Hepatology • Immunology • Infectious Disease • Novel Coronavirus Disease • Respiratory Diseases

Differential impact of GVHD prophylaxis on CMV infection and survival outcomes after cord blood transplantation in the era of letermovir. (PubMed, Transplant Cell Ther) - "This study evaluated the impact of GVHD prophylaxis with methotrexate (MTX) versus mycophenolate mofetil (MMF) after CBT on CMV infection and survival outcomes, considering the use of letermovir (LTV) prophylaxis. Importantly, LTV mitigated the disadvantage of MTX with respect to csCMVi, and patients receiving MTX with LTV exhibited a lower NRM than those receiving MMF with LTV (11.5% vs. 17.8%, P = 0.003), a finding that remained significant in multivariable analysis. This study highlights the potential for further optimization of GVHD and infectious prophylaxis strategies in CBT, thereby reducing NRM while maintaining a potent GVT effect."

Journal • Acute Graft versus Host Disease • Cytomegalovirus Infection • Graft versus Host Disease • Immunology • Infectious Disease • Oncology • Transplantation

Efficacy and safety of extended duration letermovir prophylaxis in recipients of haematopoietic stem-cell transplantation at risk of cytomegalovirus infection: a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial. (PubMed, Lancet Haematol) - P3 | "Extending the duration of letermovir prophylaxis to 200 days following HSCT is efficacious and safe in reducing the incidence of late clinically significant cytomegalovirus infection in patients at risk."

Journal • P3 data • Acute Myelogenous Leukemia • Bone Marrow Transplantation • Cytomegalovirus Infection • Graft versus Host Disease • Hematological Malignancies • Immunology • Infectious Disease • Leukemia • Oncology • Pneumonia • Respiratory Diseases • Transplantation

Bidirectional Temporal Association Between Cytomegalovirus Reactivation and Graft-Versus-Host Disease Following Allogeneic Hematopoietic Stem Cell Transplantation: A Single-Center Real-World Cohort Study. (PubMed, Viruses) - "CMV reactivation was highly prevalent after allo-HSCT and frequently preceded GVHD, supporting a bidirectional temporal relationship between these complications. Older donor age was associated with both CMV reactivation and GVHD. Although survival did not significantly differ according to CMV or GVHD status in this day-100 landmark cohort, clinically important CMV-related complications, including end-organ disease and platelet engraftment failure requiring eltrombopag, remained common. These findings indicate that a standardized pre-emptive strategy did not completely prevent CMV-associated morbidity. Because letermovir was not evaluated in this cohort, any potential benefit of prophylaxis should be interpreted as an inference from external evidence rather than as a direct finding of this study. Prospective multicenter studies incorporating immune reconstitution analyses are warranted."

Journal • Real-world evidence • Retrospective data • Acute Myelogenous Leukemia • Bone Marrow Transplantation • Cytomegalovirus Infection • Graft versus Host Disease • Hematological Disorders • Hematological Malignancies • Immunology • Oncology • Transplantation

Real-World Effectiveness and Renal Safety of Foscarnet for CMV Reactivation After Allogeneic Hematopoietic Stem Cell Transplantation. (PubMed, J Clin Med) - "Letermovir is used to prevent infections, but it is not available in many countries. Ganciclovir and valganciclovir carry a risk of bone marrow suppression...These findings suggest that close renal and electrolyte monitoring may be warranted. However, given the retrospective, single-center design, small sample size, and absence of a comparator group, the findings should be interpreted cautiously and confirmed in larger prospective comparative studies."

Journal • Real-world evidence • Acute Kidney Injury • Bone Marrow Transplantation • Cytomegalovirus Infection • Infectious Disease • Nephrology • Renal Disease • Transplantation

Incidence and risk factors of Epstein-Barr virus infection and post-transplant lymphoproliferative disorder in paediatric haploidentical allogeneic hematopoietic stem cell transplantation. (PubMed, Bone Marrow Transplant) - "We retrospectively analyzed 448 pediatric patients ( ≤ 18 years) undergoing anti-thymocyte globulin (ATG)-based haplo-HSCT with letermovir prophylaxis at Peking University People's Hospital (Oct 2022-Oct 2025), using a 1:3 propensity score-matched design...EBV reactivation and PTLD pose serious challenges, and risk factors include TBI conditioning, prior CAR-T therapy, and CMV viremia preceding EBV viremia. Preemptive cytotoxic T lymphocyte therapy may benefit high-risk patients."

Journal • Bone Marrow Transplantation • Chronic Graft versus Host Disease • Cytomegalovirus Infection • Epstein-Barr Virus Infections • Graft versus Host Disease • Immunology • Infectious Disease • Pediatrics • Transplantation

LETERMOVIR FOR SECONDARY PROPHYLAXIS OF CYTOMEGALOVIRUS INFECTION AFTER ALLOGENEIC STEM CELL TRANSPLANTATION: A SINGLE CENTER EXPERIENCE (EHA 2024) - "LMV was administered at a dose of 480 mg once daily, with a reduction to 240 mg once daily when co-administered with cyclosporine owing to a drug-drug interaction...By definition, all patients had previously received treatment for CMV reactivation (36 with valganciclovir; 6 withganciclovir; 2 with foscarnet)... LMV used as SP is effective and well tolerated in this high-risk patient population. Prospective studies on alarger cohort should be performed to validate these findings."

Clinical • Acute Graft versus Host Disease • Bone Marrow Transplantation • Cytomegalovirus Infection • Graft versus Host Disease • Immunology • Infectious Disease • Oncology • Transplantation

Favorable Adherence and Tolerability of Letermovir Versus Valganciclovir for Cytomegalovirus Prophylaxis in Kidney Transplant Recipients Aged 65 y or Older: Findings From a Randomized, Phase 3 Trial. (PubMed, Transplant Direct) - P3 | "Letermovir showed substantial advantages over valganciclovir in adherence, safety, and tolerability, supporting its use as an important option for cytomegalovirus disease prophylaxis for older patients undergoing kidney transplantation. ClinicalTrials.gov, NCT03443869."

Clinical • Journal • P3 data • Cytomegalovirus Infection • Hematological Disorders • Infectious Disease • Leukopenia • Neutropenia • Transplantation

TCR-αβ/CD 19 Depleted Graft Versus T Replete Graft With Post-Transplant Cyclophosphamide in Children Undergoing Haploidentical Donor Hematopoietic Stem Cell Transplantation for Inborn Errors of Immunity: A Comparative Analysis From India. (PubMed, Pediatr Transplant) - "Survival was superior in the T depleted cohort as compared to the T replete group, with viral reactivation remaining a persisting challenge. Letermovir prophylaxis and memory cell add-back would be potential strategies to improve survival."

Clinical • Journal • Retrospective data • Acute Graft versus Host Disease • Bone Marrow Transplantation • Chronic Graft versus Host Disease • Graft versus Host Disease • Immunology • Transplantation