[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"health-study-detail:100630519":3},{"organization":4,"armGroups":7,"interventions":17,"overallOfficials":11,"centralContacts":23,"locations":29,"responsibleParty":47,"collaborators":11,"id":49,"slug":11,"hasResults":50,"nctId":51,"briefTitle":52,"officialTitle":53,"acronym":11,"eligibilityCriteria":54,"healthyVolunteers":50,"sex":55,"minAge":11,"maxAge":56,"enrollmentInfo":57,"targetDuration":11,"studyType":60,"phases":61,"briefSummary":63,"conditions":64,"keywords":67,"overallStatus":32,"whyStopped":11,"lastUpdateSubmitDate":71,"lastUpdatePostDateStruct":72,"startDateStruct":75,"completionDateStruct":77,"leadSponsor":79,"locationsCount":80},{"fullName":5,"class":6},"Beijing Children's Hospital","OTHER",[8,14],{"label":9,"type":10,"description":11,"interventionNames":12},"Children with Letermovir for Cytomegalovirus prophylaxis after HSCT","EXPERIMENTAL",null,[13],"Drug: Letermovir",{"label":15,"type":16,"description":11,"interventionNames":11},"Children with preemptive therapy, without Letermovir for Cytomegalovirus prophylaxis after HSCT","NO_INTERVENTION",[18],{"type":19,"name":20,"description":21,"armGroupLabels":22,"otherNames":11},"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.",[9],[24],{"name":25,"role":26,"phone":27,"phoneExt":11,"email":28},"Jun Yang, Doctor","CONTACT","+86 13699293825","yangjundabby@outlook.com",[30],{"facility":31,"status":32,"city":33,"state":34,"zip":35,"country":36,"countryCode":37,"cosmosGeoPoint":38,"geoPoint":43,"contacts":44},"Beijing Children's Hospital, Capital Medical University","RECRUITING","Beijing","Beijing Municipality","100032","China","CN",{"type":39,"coordinates":40},"Point",[41,42],116.39723,39.9075,{"lat":42,"lon":41},[45],{"name":46,"role":26,"phone":27,"phoneExt":11,"email":28},"Jun Yang",{"type":48,"investigatorFullName":46,"investigatorTitle":5,"investigatorAffiliation":5,"oldNameTitle":11,"oldOrganization":11},"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":58,"type":59},80,"ESTIMATED","INTERVENTIONAL",[62],"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.",[65,66,20],"EBV-associated T\u002FNK-cell Lymphoproliferative Diseases","Refractory\u002FRelapsed EBV-related Hemophagocytic Lymphohistiocytosis",[68,20,69,70],"EBV","EBV-associated T\u002FNK-cell lymphoproliferative diseases","refractory\u002Frelapsed EBV-related hemophagocytic lymphohistiocytosis","2026-03-18",{"date":73,"type":74},"2026-03-23","ACTUAL",{"date":76,"type":74},"2025-10-01",{"date":78,"type":59},"2026-12-31",{"name":5,"class":6},1]