Prevymis (letermovir) / Merck (MSD), AiCuris - LARVOL DELTA

Threshold for cytomegalovirus DNA PCR for preemptive treatment after allogeneic stem cell transplantation. (PubMed, Int J Hematol) - "In low-risk patients, a threshold of 500-750 IU/mL balances avoiding spontaneous resolution and increasing delayed treatment. PCR thresholds of 50 and 150 IU/mL may be appropriate for initiating preemptive therapy in high-risk patients treated and not treated with letermovir, respectively, while 500-750 IU/mL may be optimal for low-risk patients."

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

Secondary Prophylaxis With Bioequivalent Generic Letermovir in Haploidentical Hematopoietic Stem Cell Transplantation: A Case Report. (PubMed, Cureus) - "Cytomegalovirus (CMV) reactivation poses a significant risk post-allogeneic hematopoietic stem cell transplantation (HSCT), particularly in high-risk settings. The episode was successfully managed in the outpatient setting with oral valganciclovir. This case highlights the importance of sustained CMV prophylaxis and the role of accessible antiviral strategies in optimizing transplant outcomes."

Journal • Acute Myelogenous Leukemia • Bone Marrow Transplantation • Cytomegalovirus Infection • Hematological Malignancies • Leukemia • Oncology • Transplant Rejection • Transplantation

Real-World Off-Label Use of Letermovir Prophylaxis for Cytomegalovirus Prevention in Non-Kidney Solid Organ Transplant Recipients: Outcomes, Safety, and Review of Literature. (PubMed, Clin Transplant) - "In this cohort of non-kidney solid organ recipients, letermovir was well tolerated with low rates of clinically significant breakthrough infections. Early discontinuation was commonly cost-driven. Post-prophylaxis delayed-onset CMV infections remain common. Large-scale registry studies are needed to provide evidence for use of letermovir in non-kidney transplant recipients."

Journal • Real-world evidence • Retrospective data • Review • Cytomegalovirus Infection • Infectious Disease • Solid Organ Transplantation • Transplantation

ULTRA-LOW SEVERE AGVHD AND FAVORABLE SAFETY PROFILE WITH ABATACEPT + ATG IN CNI-INTOLERANT HIGH-RISK ALLOGENEIC TRANSPLANT RECIPIENTS (EBMT 2026) - "Letermovir prophylaxis began within 6 days post-transplant. Abatacept combined with ATG yielded a low incidence of severe aGVHD with acceptable infectious and toxicity profiles in CNI-intolerant, high-risk HSCT recipients. The incidence of EBV viremia is consistent with previous reports and comparable to that in HLA-mismatched transplants. This regimen represents a feasible alternative prophylaxis strategy and warrants validation in larger prospective studies."

Clinical • Acute Graft versus Host Disease • Aplastic Anemia • Bone Marrow Transplantation • Chronic Graft versus Host Disease • Gastrointestinal Disorder • Graft versus Host Disease • Hematological Malignancies • Immunology • Infectious Disease • Respiratory Diseases • T Acute Lymphoblastic Leukemia • Transplantation

INCIDENCE AND RISK FACTORS FOR POOR GRAFT FUNCTION AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION WITH POST-TRANSPLANT CYCLOPHOSPHAMIDE IN A MULTICENTER COHORT (EBMT 2026) - "GVHD prophylaxis consisted of PTCy plus mycophenolate mofetil and a calcineurin inhibitor, using peripheral blood or bone marrow as the graft source...Management included thrombopoietin receptor agonists (TPO-Ras) (n=21), TPO-Ras plus filgrastim and erythropoietin (n=7), filgrastim alone (n=13), or transfusional support; seven patients required second-line therapy (CD34⁺ boost n=3, change of TPO-Ras n=3, second transplant n=1)...Letermovir prophylaxis was used in 56/427 seropositive receptors... In this multicenter cohort of allo-HSCT recipients receiving PTCy-based GVHD prophylaxis, the incidence of PGF was not higher than that reported in non-PTCy platforms. Bone marrow graft source, CMV reactivation within 6 months, and donor-specific anti-HLA antibodies were the main independent risk factors for PGF. These findings support optimization of graft quality and intensified CMV monitoring and prophylaxis strategies in patients receiving PTCy."

Clinical • Post-transplantation • Bone Marrow Transplantation • Graft versus Host Disease • Hematological Disorders • Hematological Malignancies • Immunology • Lymphoma • Transplantation

Intravenous Brincidofovir Effectively Reduces CMV Dnaemia In Antiviral Experienced Immunocompromised Patients: Results of a Phase 2a Clinical Trial (TCT-ASTCT-CIBMTR 2026) - P2 | "Most patients (7/9 per Cohort) had failed ≥1 prior CMV antiviral (n=12 GCV or valGCV, 4 foscarnet, 4 letermovir, and 2 maribavir). IV BCV was effective in reducing CMV DNAemia and was reasonably well tolerated in this population of pre-treated immunocompromised patients. IV BCV is a potential treatment for patients with limited options. These data support further study of IV BCV for treatment of CMV infections."

Clinical • Late-breaking abstract • P2a data • Bone Marrow Transplantation • Cytomegalovirus Infection • Infectious Disease

Ganciclovir Pharmacokinetic Monitoring in a Pediatric Stem Cell Transplant Recipient with Human Cytomegalovirus Viremia: A Case Report (TCT-ASTCT-CIBMTR 2026) - "He failed to clear CMV with standard valganciclovir and ganciclovir pediatric dosing; resistance testing was negative... After foscarnet discontinuation, ganciclovir was continued at home...Letermovir was subsequently prescribed for secondary prophylaxis... Inadequate ganciclovir exposure may lead to treatment failure or antiviral resistance. To our knowledge , this is the first reported case of AUC -guided ganciclovir dosing in a pediatric SCT patient with CMV viremia. AUC-guided dosing is a potentially safe and effective option for pediatric patients unable to clear CMV with traditional dosing strategies ."

Case report • Clinical • PK/PD data • Cytomegalovirus Infection • Gastroenterology • Gastrointestinal Disorder • Hematological Disorders • Hepatitis C • Hepatology • Immunology • Inflammation • Pediatrics • Pneumonia • Transplantation

Letermovir Improves Real-World, 5-Year Overall Survival Among CMV Seropositive Allogeneic Hematopoietic Cell Transplant Recipients (TCT-ASTCT-CIBMTR 2026) - "3. Compare overall survival rates between CMV-seropositive subjects treated with letermovir and CMV- seronegative subjects who did not receive letermovir."

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

Comparison of Viral Infection Rates after T-cell Depletion in Pediatric HCT: Alemtuzumab Vs Post-Transplant Cyclophosphamide (TCT-ASTCT-CIBMTR 2026) - "The alemtuzumab group was younger (median 7.7 vs 13.9 years) and, as expected, primarily received MUD transplants (85%), while the PTCy group mainly received haploidentical transplants (63%); letermovir use was similar between groups (Table 1). In this pediatric HCT cohort, viral infection rates were comparable between alemtuzumab and PTCy. Despite the small sample size, both T-cell depletion approaches appear to pose comparable infectious risks, supporting tailored platform choice based on donor and clinical factors. 1."

Clinical • Post-transplantation • Infectious Disease • Pediatrics • Transplantation

A Journey Towards Better Outcomes : The Evolution of Haploidentical HSCT from Ptcy to Αβ T-cell Depletion and Memory Addback in LMIC Context (TCT-ASTCT-CIBMTR 2026) - "This study analyses haploidentical HSCT for IEI over 16 years at our centre, focusing on the transition from post-transplant cyclophosphamide (PTCy) to TCRαβ/CD19 depletion and the introduction of CD45RO+ memory T-cell add-back...With additional measures such as letermovir prophylaxis and virus-specific T-cell infusions, survival outcomes in low- and middle-income countries could approach that of high-income setting... The evolution from PTCy-based to TCRαβ/CD19-depleted haploidentical HSCT has significantly improved outcomes in children with IEI. Incorporating CD45RO+ memory T-cell add-back has further enhanced immune reconstitution without increasing GVHD risk. Although viral reactivation remains common, early immune recovery and effective antiviral therapy have reduced mortality."

Acute Graft versus Host Disease • Bone Marrow Transplantation • Chronic Graft versus Host Disease • Graft versus Host Disease • Hematological Malignancies • Immunology • Infectious Disease

Letermovir Prophalaxis for CMV in Haplo HSCT - Early Experience from Single Center Fron North India (TCT-ASTCT-CIBMTR 2026) - "Second patient had cytopenias and was given pre emptive therapy with Valganciclovir. Letermovir is a highly effective drug in preventing CMV reactivation in high risk transplants especially Haploidentical stem cell transplants. Efficacy of Letermovir in preventing CMV reactivation Side effects of Letermovir Outcome of patients with CMV prophylaxis post Haplo HSCT"

Clinical • Bone Marrow Transplantation • Hematological Disorders • Infectious Disease • Septic Shock

Comparison of Letermovir Versus High-Dose Valacyclovir for Cytomegalovirus Prophylaxis Following Allogeneic Hematopoietic Stem Cell Transplantation (TCT-ASTCT-CIBMTR 2026) - "Prior studies comparing letermovir (LET) and high-dose valacyclovir (VAL) for CMV prophylaxis primarily included high-risk patients, such as those with haploidentical or mismatched unrelated donors receiving post-transplant cyclophosphamide (PTCy)...Tacrolimus/methotrexate was the most frequent GVHD prophylaxis (65%)... No significant difference was observed in CMV infection rates between LET and VAL prophylaxis, although the incidence trended lower with LET. LET was associated with a higher rate of HHV-6 reactivation. Rates of acute and chronic GVHD, as well as 6-month survival, did not differ between groups."

Acute Graft versus Host Disease • Acute Lymphocytic Leukemia • Acute Myelogenous Leukemia • Bone Marrow Transplantation • Chronic Graft versus Host Disease • Cytomegalovirus Infection • Graft versus Host Disease • Hematological Malignancies • Immunology • Leukemia • Myelodysplastic Syndrome • Transplantation

Initial Experience with Generic Letermovir [Anvimo] in Preventing Cytomegalovirus Reactivation in Hematopoietic Stem Cell Transplant Recipients Who Are at a High Risk of Infection. (TCT-ASTCT-CIBMTR 2026) - "Anvimo was started following engraftment at a dose of 240 mg [with cyclosporine] or 480 mg till Day 100...Majority of patients with reactivation received ganciclovir as pre-emptive therapy and cleared the viremia... Generic Letermovir [Anvimo] in useful in reducing the incidence of CMV reactivation especially in haplo-identical transplants. More long-term data is needed to look at secondary reactivation and survival. 1."

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

A Novel Indicator of CMV Infection after Allo-HCT: Current CMV Reactivation (TCT-ASTCT-CIBMTR 2026) - "Using this indicator, we compared the time course of CMVR in patients who did or did not receive letermovir (LTV) prophylaxis (the LTV or no-LTV groups)...3 . To assess the impacts of well-established and potentially underestimated factors on CMV infection after HCT."

Cytomegalovirus Infection • Hematological Malignancies • Infectious Disease • Lymphoma • Multiple Myeloma

Real-World Effectiveness of Letermovir Prophylaxis after Allogeneic Hematopoietic Cell Transplantation in a Middle-Income Country Setting (TCT-ASTCT-CIBMTR 2026) - "Letermovir prophylaxis was associated with a marked reduction and delay in CMV reactivation and the absence of refractory/resistant CMV infection. These findings extend current evidence to a middle-income country, underscoring the need for equitable access to CMV prevention strategies in resource-limited settings. 1 ."

Clinical • Real-world • Real-world effectiveness • Real-world evidence • Chronic Kidney Disease • Cytomegalovirus Infection • Infectious Disease • Nephrology • Renal Disease • Transplantation

Pausing for Halftime: A Stratified Analysis of Epidemiological Characteristics and Outcomes in CMV-Seropositive Allogeneic HSCT Recipients with Cscmvi before and after Day 100 (TCT-ASTCT-CIBMTR 2026) - "Most patients were treated with Valganciclovir (90%). Prospective studies are needed to evaluate safety, efficacy, and mortality benefits of prolonged prophylaxis in high-risk subgroups. -Descriptive analysis comparing epidemiological characteristics between CMV-seropositive recipients of allo-HSCT patients transplanted at the Cleveland Clinic who developed early vs late csCMVi following primary Letermovir prophyaxis -Identification of potential risk factors for delayed csCMVi that may potentially inform decisions around extending CMV prophylaxis beyond day 100 post-transplant -Stratified comparison of various outcomes, including incidence of invasive disease, recurrent disease, hematological disease relapse, all-cause mortality, time to mortality from csCMVi/ transplant"

Clinical • Bone Marrow Transplantation • Cytomegalovirus Infection • Graft versus Host Disease • Hematological Disorders • Immunology • Infectious Disease

Evaluating CMV Infection and Reactivation after Emapalumab: A Retrospective Evaluation of Letermovir Prophylaxis (TCT-ASTCT-CIBMTR 2026) - "3. Assess the safety of CMV prophylaxis in patients receiving emapalumab."

Retrospective data • Cytomegalovirus Infection • Hemophagocytic lymphohistiocytosis • Immunology • Infectious Disease • Rare Diseases • IFNG

Immuneai-CMV (Phase-I): Precision Phenotyping Reveals Heterogeneous CMV–GVHD Trade-Offs Following Allogeneic HCT (TCT-ASTCT-CIBMTR 2026) - "Introduction Post-transplant cyclophosphamide (PTCy) is widely used for GVHD prophylaxis after allogeneic hematopoietic cell transplantation (HCT), yet its impact on cytomegalovirus (CMV) infection risk varies across subgroups...Objectives To identify patient phenotypes with differential CMV risk and heterogeneous effects of PTCy versus methotrexate (MTX)–based GVHD prophylaxis, enabling precision prophylaxis selection...In the day +100 landmark cohort, the model achieved AUC ≈ 0.76, and targeting the top 20–30% by predicted risk captured ~70% of post-day +100 CMV events, supporting risk-guided letermovir continuation and cost savings...4. Interpret clinically actionable metrics (absolute risk reduction, number needed to harm) to support evidence-based shared decision-making in HCT prophylaxis selection."

Heterogeneity • Acute Graft versus Host Disease • Cytomegalovirus Infection • Graft versus Host Disease • Immunology • Infectious Disease

Cytomegalovirus End-Organ Disease after Allogenic Hematopoietic Cell Transplant: Descriptive and Comparative Analysis in the Era of Letermovir Prophylaxis (TCT-ASTCT-CIBMTR 2026) - "HCT recipients are still at risk for CMV EOD although the incidence decreased with LTV primary prophylaxis. Across all EOD cases, mortality was significantly higher in patients with pneumonitis compared to GI disease. HCT patients who received LTV for primary prophylaxis had more often CMV EOD after day 100 post-transplant but with trends towards lower ACM and NRM at 24 or 48 weeks post- transplant."

Bone Marrow Transplantation • Cytomegalovirus Infection • Gastrointestinal Disorder • Inflammation • Pneumonia • Transplantation

Immune Reconstitution Associated with CMV Reactivation after Discontinuation of Letermovir Prophylaxis - a Prospective Study (TCT-ASTCT-CIBMTR 2026) - "In contrast, the decline of activated T cells provides additional evidence for the CMV-derived suppression of the immune system that could increase the risk of secondary infections. - late CMV infection incidence - terminally differentiated T EM cells as a candidate biomarker to predict CMV reactivations - impact of CMV reactivations on the immune system"

Clinical • Cytomegalovirus Infection • Infectious Disease • CCR7 • CD8

Joint Use of Rabbit ATG and Posttransplant Immunosuppression with Cyclophosphamide for HLA-Matched Peripheral Blood Hematopoietic Cell Transplantation, a Calcineurin Inhibitor-Free Graft-Versus-Host Disease Prophylaxis – the NCT06299462 Jurassic Phase I/II Trial (TCT-ASTCT-CIBMTR 2026) - P1/2 | "One patient with measurable residual disease had steroid-refractory cGVHD and is on sirolimus...No patient received letermovir...2023. PMID: 37140099 Calcineurin inhibitor-free GVHD prophylaxis for HLA-matched PBSC donors with ATG and PTCy is feasible Although CMV reactivation appears to be high, there was no case of CMV disease CRS following graft infusion seems high"

P1/2 data • Post-transplantation • Preclinical • Acute Graft versus Host Disease • Chronic Graft versus Host Disease • Graft versus Host Disease • Hematological Disorders • Hematological Malignancies • Hepatology • Hodgkin Lymphoma • Immunology • Leukemia • Liver Failure • Lymphoma • Myelodysplastic Syndrome • Thrombosis • Transplantation

Incidence of Cytomegalovirus Infections after Standard of Care CD19 CAR-T cell Therapy: A Retrospective Analysis. (TCT-ASTCT-CIBMTR 2026) - "Methods : We conducted a single-center retrospective study of patients ≥18 years with B-cell lymphomas who received standard-of-care CAR-T therapy (axicabtagene ciloleucel (Yescarta), brexucabtagene autoleucel (Tecartus), lisocabtagene maraleucel (Breyanzi), or tisagenlecleucel (Kymriah)) between January 2023 and October 2024 at MD Anderson Cancer Center. CMV viremia is increasingly recognized as a complication following CAR-T therapy, particularly with Yescarta and Tecartus. The effect of CMV viremia on CAR T cell morbidity and mortality will need further exploration. Prophylactic strategies such as letermovir can be considered."

CAR T-Cell Therapy • Retrospective data • B Cell Lymphoma • Cytomegalovirus Infection • Diffuse Large B Cell Lymphoma • Follicular Lymphoma • Hematological Malignancies • Infectious Disease • Lymphoma • Mantle Cell Lymphoma • Non-Hodgkin’s Lymphoma

ETANERCEPT AS SECOND-LINE THERAPY FOR STEROID-REFRACTORY GVHD: FEASIBILITY, SAFETY, AND OUTCOMES (EBMT 2026) - "All patients received calcineurin inhibitor–based GVHD prophylaxis in combination with either antithymocyte globulin or post-transplant cyclophosphamide.Eligible patients had glucocorticoid- and ruxolitinib-refractory disease...Within 100 days post-transplant, only one patient had CMV reactivation despite no letermovir prophylaxis as is standard practice in Australia... In this small, high-risk cohort, etanercept administered as a second-line agent following ruxolitinib for steroid-refractory GVHD demonstrated feasible use with treatment-related toxicity analogous to other immunosuppressants. Its introduction occurred early in the disease course as a rescue escalation rather than as prolonged salvage, as is reflected in etanercept's administration schedule as a subcutaneous injection given over an eight-week finite course. Among patients with SR-aGVHD, a meaningful steroid-sparing effect was observed, with over one-third achieving substantial corticosteroid reduction..."

Clinical • Acute Graft versus Host Disease • Bone Marrow Transplantation • Chronic Graft versus Host Disease • Gastrointestinal Disorder • Graft versus Host Disease • Immunology

ALEMTUZUMAB-CONDITIONED HAPLOIDENTICAL HEMATOPOIETIC CELL TRANSPLANTATION CONFERS EXCELLENT SURVIVAL WITH LIMITED GVHD IN FANCONI ANEMIA (EBMT 2026) - "We present outcomes for patients with FA who underwent haploidentical transplantation with alemtuzumab-based conditioning and GVHD prophylaxis with a modified post-transplant cyclophosphamide (PTCY)...All subjects received bone marrow from haploidentical donors and conditioning with Fludarabine 150mg/m², Total Body Irradiation (TBI) 200cGy, and Alemtuzumab 0,6-0,7mg/kg. GVHD prophylaxis consisted of PTCY 50-60 mg/kg (total dose), Cyclosporin, and Mycofenolate Mofetil...Patients didn't receive letermovir prophylaxis but were successfully treated with preemptive therapy, with no evidence of CMV disease... The modified haploidentical approach incorporating alemtuzumab and PTCY achieves excellent survival outcomes in FA by decreasing rejection and TRM. The RIC approach minimizes toxicity, but careful consideration of TBI exposure and GVHD-associated malignancy risk remains a concern. The addition of alemtuzumab reduced the incidence and severity of GVHD compared to..."

Acute Graft versus Host Disease • Anemia • Aplastic Anemia • Chronic Graft versus Host Disease • Cytomegalovirus Infection • Graft versus Host Disease • Head and Neck Cancer • Immunology • Infectious Disease • Oral Cancer • Solid Tumor • Transplantation

HUMAN HERPES VIRUS 6 INFECTION IN ALLOGENEIC STEM CELL TRANSPLANTATION RECEIVING POST-TRASPLANT CYCLOPHOSPHAMIDE (EBMT 2026) - "Clinical Trial Registry: Not Applicable Background: HHV-6 viremia is frequent after allogeneic hematopoietic cell transplantation (allo-HCT), but there is great difficulty in knowing its pathogenic capacity. Epidemiology of HHV6 infection is changing in allo-HCT due to the new approaches in GvHD prophylaxis (PTCy regimen) and Letermovir prophylaxis for CMV infection (excellent control on CMV infection). Gastrointestinal infection is the most frequent organ presentation with a good response to antiviral treatment."

CNS Disorders • Cytomegalovirus Infection • Epstein-Barr Virus Infections • Gastroenterology • Gastrointestinal Disorder • Graft versus Host Disease • Hematological Disorders • Hepatology • Immunology • Infectious Disease • Inflammation • Transplantation