[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"health-study-detail:100630519":3},{"organization":4,"outcomesModule":7,"designInfo":23,"detailedDescription":26,"studyPopulation":26,"armGroups":30,"interventions":39,"overallOfficials":26,"centralContacts":45,"locations":51,"responsibleParty":69,"collaborators":26,"id":71,"slug":26,"hasResults":72,"nctId":73,"briefTitle":74,"officialTitle":75,"acronym":26,"eligibilityCriteria":76,"healthyVolunteers":72,"sex":77,"minAge":26,"maxAge":78,"enrollmentInfo":79,"targetDuration":26,"studyType":82,"phases":83,"briefSummary":85,"conditions":86,"keywords":89,"overallStatus":54,"whyStopped":26,"lastUpdateSubmitDate":93,"lastUpdatePostDateStruct":94,"startDateStruct":97,"completionDateStruct":99,"leadSponsor":101,"locationsCount":102},{"fullName":5,"class":6},"Beijing Children's Hospital","OTHER",{"primaryOutcomes":8,"secondaryOutcomes":13,"otherOutcomes":18},[9],{"measure":10,"description":11,"timeFrame":12},"Incidence of Clinically Significant CMV Infection (cs-CMVi) and EBV Infection (cs-EBVi)","To evaluate the incidence of clinically significant CMV and EBV infections in pediatric patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT) with or without letermovir prophylaxis.","Up to 180 days and 360 days post-transplant",[14],{"measure":15,"description":16,"timeFrame":17},"Incidence of Other Viral Infections and Transplant-Related Complications","To assess the incidence of other viral infections (e.g., BKV, HHV-6\u002F7, RSV, ADV, HSV), graft-versus-host disease (GvHD), post-transplant lymphoproliferative disorder (PTLD), thrombotic microangiopathy (TMA), graft failure, relapse, overall survival (OS), and immune reconstitution (T\u002FB\u002FNK cell counts and function).","Up to 100, 180, 270, and 360 days post-transplant",[19],{"measure":20,"description":21,"timeFrame":22},"Safety and Tolerability of Letermovir in Pediatric allo-HSCT Recipients","To monitor adverse events (AEs) and serious adverse events (SAEs) related to letermovir prophylaxis, including gastrointestinal symptoms, liver function abnormalities, cardiac events, and other treatment-emergent AEs.","From initiation of letermovir (Day 0-28 post-transplant) until 30 days after discontinuation (up to approximately 360 days post-transplant)",{"allocation":24,"interventionModel":25,"interventionModelDescription":26,"primaryPurpose":27,"observationalModel":26,"timePerspective":26,"maskingInfo":28},"NON_RANDOMIZED","PARALLEL",null,"PREVENTION",{"masking":29,"maskingDescription":26,"whoMasked":26},"NONE",[31,36],{"label":32,"type":33,"description":26,"interventionNames":34},"Children with Letermovir for Cytomegalovirus prophylaxis after HSCT","EXPERIMENTAL",[35],"Drug: Letermovir",{"label":37,"type":38,"description":26,"interventionNames":26},"Children with preemptive therapy, without Letermovir for Cytomegalovirus prophylaxis after HSCT","NO_INTERVENTION",[40],{"type":41,"name":42,"description":43,"armGroupLabels":44,"otherNames":26},"DRUG","Letermovir","Arm 1 (Letermovir Prophylaxis): Pediatric patients receive oral letermovir once daily from day 0 to day 100 post-transplant. Prophylaxis may be extended to day 200 if high-risk factors persist (steroid use, poor immune reconstitution). Dosing: 480mg (≥30kg), 240mg (15-30kg), 120mg (7.5-15kg), 80mg (6-7.5kg); halved if co-administered with cyclosporine.\n\nArm 2 (Control): Historical control cohort (2018-2023) receiving no routine CMV prophylaxis; preemptive therapy with ganciclovir\u002Ffoscarnet initiated only when plasma PCR exceeds threshold.",[32],[46],{"name":47,"role":48,"phone":49,"phoneExt":26,"email":50},"Jun Yang, Doctor","CONTACT","+86 13699293825","yangjundabby@outlook.com",[52],{"facility":53,"status":54,"city":55,"state":56,"zip":57,"country":58,"countryCode":59,"cosmosGeoPoint":60,"geoPoint":65,"contacts":66},"Beijing Children's Hospital, Capital Medical University","RECRUITING","Beijing","Beijing Municipality","100032","China","CN",{"type":61,"coordinates":62},"Point",[63,64],116.39723,39.9075,{"lat":64,"lon":63},[67],{"name":68,"role":48,"phone":49,"phoneExt":26,"email":50},"Jun Yang",{"type":70,"investigatorFullName":68,"investigatorTitle":5,"investigatorAffiliation":5,"oldNameTitle":26,"oldOrganization":26},"PRINCIPAL_INVESTIGATOR","100630519",false,"NCT07488728","Letermovir Prophylaxis in Children With EBV-Positive T\u002FNK-Cell Lymphoproliferative Disease and Refractory\u002FRelapsed EBV-Associated Hemophagocytic Lymphohistiocytosis","Impact of Letermovir Prophylaxis on Viral Infections After Allogeneic Hematopoietic Stem Cell Transplantation in Children With EBV-Positive T\u002FNK-Cell Lymphoproliferative Disease and Refractory\u002FRelapsed EBV-Associated Hemophagocytic Lymphohistiocytosis","Inclusion Criteria:\n\n* Diagnosed with EBV-positive T\u002FNK lymphoproliferative disease (EBV-T\u002FNK LPD) according to ICC 2022 criteria, or diagnosed with refractory\u002Frelapsed EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH) according to the 2004-HLH diagnostic criteria;\n* Undergoing first allogeneic hematopoietic stem cell transplantation (allo-HSCT) at the study center;\n* Age \\\u003C 18 years;\n* CMV seropositive (IgG+) prior to transplantation;\n* Presence of at least one high-risk factor for CMV infection: haploidentical transplantation, HLA-mismatched transplantation, receipt of ATG (including ATLG\u002FALG) in conditioning, sustained corticosteroid use post-conditioning, donor\u002Frecipient CMV serostatus mismatch, or positive NGS result pre-transplant.\n\nExclusion Criteria:\n\n* History of CMV end-organ disease within 6 months prior to enrollment;\n* Severe hepatic dysfunction (defined as Child-Pugh Class C);\n* End-stage renal impairment with creatinine clearance \\\u003C 10 mL\u002Fmin (calculated by Cockcroft-Gault equation);\n* Prior allogeneic hematopoietic stem cell transplantation;\n* Expected survival ≤ 3 months;\n* Received radiation therapy during conditioning;\n* Initiation of letermovir prophylaxis after day 28 post-transplant;\n* Letermovir dosage or administration not in accordance with the prescribing information;\n* Lack of signed informed consent.","ALL","18 Years",{"count":80,"type":81},80,"ESTIMATED","INTERVENTIONAL",[84],"NA","This study investigates the impact of letermovir prophylaxis on viral infections (including CMV, EBV, BKV, HHV-6\u002F7, RSV, ADV, HSV, etc.) following allogeneic hematopoietic stem cell transplantation in pediatric patients with EBV-associated T\u002FNK-cell lymphoproliferative diseases and refractory\u002Frelapsed EBV-related hemophagocytic lymphohistiocytosis. Additionally, we examine its effects on other transplantation complications, including engraftment failure, graft-versus-host disease (GvHD), disease relapse, thrombotic microangiopathy (TMA), overall survival (OS), post-transplant lymphoproliferative disorder (PTLD) incidence, and immune reconstitution.",[87,88,42],"EBV-associated T\u002FNK-cell Lymphoproliferative Diseases","Refractory\u002FRelapsed EBV-related Hemophagocytic Lymphohistiocytosis",[90,42,91,92],"EBV","EBV-associated T\u002FNK-cell lymphoproliferative diseases","refractory\u002Frelapsed EBV-related hemophagocytic lymphohistiocytosis","2026-03-18",{"date":95,"type":96},"2026-03-23","ACTUAL",{"date":98,"type":96},"2025-10-01",{"date":100,"type":81},"2026-12-31",{"name":5,"class":6},1]