{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T04:54:59Z","timestamp":1790571299418,"version":"4.1.0"},"reference-count":20,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2025,11,11]],"date-time":"2025-11-11T00:00:00Z","timestamp":1762819200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"},{"start":{"date-parts":[[2025,11,11]],"date-time":"2025-11-11T00:00:00Z","timestamp":1762819200000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Haemophilia"],"published-print":{"date-parts":[[2026,1]]},"abstract":"ABSTRACT<\/jats:title>\n \n Background<\/jats:title>\n Limited real\u2010world data exist on recombinant fusion protein\u2010linking coagulation factor IX (FIX) with albumin (rIX\u2010FP) in paediatric previously untreated patients (PUPs) with haemophilia B, particularly in infants.<\/jats:p>\n <\/jats:sec>\n \n Aims<\/jats:title>\n To evaluate the treatment patterns, safety and efficacy of rIX\u2010FP in paediatric PUPs in Japan.<\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n Retrospective chart review of 21 PUPs who initiated rIX\u2010FP between May 2017 and September 2023, with follow\u2010up to June 2024.<\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n At first administration, 95% (19\/20) of patients were <2\u00a0years old, and 84% (16\/19) weighed <10\u00a0kg. The mean treatment duration was 27\u00a0months. Prophylaxis was received by 90% (18\/20), with 56% (10\/18) on every 2\u00a0weeks and 44% (8\/18) on a weekly regimen. The proportion of patients with \u226525 exposure days was 100% in the weekly and 90% in every 2\u00a0weeks groups. No patients developed inhibitors or discontinued treatment. Among those on prophylaxis, no bleeding events occurred in patients \u22652\u00a0years, while 88% (15\/17) of those <2\u00a0years experienced superficial perioral, or subcutaneous bleeding, with 2\/15 requiring treatment. Every 2\u00a0weeks regimen had lower FIX trough levels than the weekly regimen (median: 4% vs. 10%) and a higher annualized bleeding rate (ABR: 8.2 vs. 4.9). The most common bleeding type was traumatic (ABR: 4.8), followed by spontaneous (1.6) and undetermined (0.7). All treated bleeds resolved successfully. In vivo recovery (IVR) positively correlated with body weight in patients <10\u00a0kg.<\/jats:p>\n <\/jats:sec>\n \n Conclusion<\/jats:title>\n This study provides real\u2010world insights into rIX\u2010FP use in paediatric PUPs, demonstrating its favourable safety, effective prophylaxis, and lower IVR in infants.<\/jats:p>\n <\/jats:sec>","DOI":"10.1111\/hae.70161","type":"journal-article","created":{"date-parts":[[2025,11,12]],"date-time":"2025-11-12T07:53:26Z","timestamp":1762934006000},"page":"71-79","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Safety, Efficacy and Treatment Patterns of rIX\u2010FP in Previously Untreated Paediatric Haemophilia B Patients: A Retrospective Chart Review in Japan"],"prefix":"10.1111","volume":"32","author":[{"given":"Keiji","family":"Nogami","sequence":"first","affiliation":[{"name":"Department of Pediatrics Nara Medical University Kashihara Nara Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chiai","family":"Nagae","sequence":"additional","affiliation":[{"name":"Department of Pediatrics St. Marianna University School of Medicine Kawasaki Kanagawa Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masatoshi","family":"Yono","sequence":"additional","affiliation":[{"name":"CSL Behring K.K. Kita\u2010Aoyama Minato\u2010ku Tokyo Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Naoki","family":"Terasaka","sequence":"additional","affiliation":[{"name":"CSL Behring K.K. Kita\u2010Aoyama Minato\u2010ku Tokyo Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2025,11,11]]},"reference":[{"key":"e_1_2_12_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(15)01123-X"},{"key":"e_1_2_12_3_1","doi-asserted-by":"publisher","DOI":"10.1111\/hae.14046"},{"key":"e_1_2_12_4_1","unstructured":"Outsourcing project of Ministry of Health Labour and Welfare.National Survey of Japan on Coagulation Disorders in 2023. Accessed on March 26 2025. (https:\/\/api\u2010net.jfap.or.jp\/image\/data\/blood\/r05_research\/r05_research.pdf)."},{"key":"e_1_2_12_5_1","doi-asserted-by":"publisher","DOI":"10.3324\/haematol.2019.239160"},{"key":"e_1_2_12_6_1","doi-asserted-by":"publisher","DOI":"10.1007\/s40265-016-0679-8"},{"key":"e_1_2_12_7_1","doi-asserted-by":"publisher","DOI":"10.1160\/TH16-03-0179"},{"key":"e_1_2_12_8_1","doi-asserted-by":"publisher","DOI":"10.1055\/s-0040-1705116"},{"key":"e_1_2_12_9_1","doi-asserted-by":"publisher","DOI":"10.1111\/jth.14778"},{"key":"e_1_2_12_10_1","unstructured":"PMDA.Idelvion Approved Package Insert. Tokyo Japan. Accessed on March 26 2025. (https:\/\/pins.japic.or.jp\/pdf\/newPINS\/00068260.pdf)."},{"key":"e_1_2_12_11_1","doi-asserted-by":"publisher","DOI":"10.1111\/jth.13444"},{"key":"e_1_2_12_12_1","article-title":"Population Pharmacokinetics Modeling of rIX\u2010FP for Optimizing Hemophilia B Treatment Regimens, Frontiers in Pediatrics, under review","author":"Terasaka N.","journal-title":"Scientific Reports"},{"key":"e_1_2_12_13_1","doi-asserted-by":"publisher","DOI":"10.1055\/s-0038-1660817"},{"key":"e_1_2_12_14_1","doi-asserted-by":"publisher","DOI":"10.1111\/hae.14602"},{"key":"e_1_2_12_15_1","doi-asserted-by":"publisher","DOI":"10.1160\/TH14-10-0826"},{"key":"e_1_2_12_16_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2516.2009.02039.x"},{"key":"e_1_2_12_17_1","doi-asserted-by":"publisher","DOI":"10.1111\/ejh.13193"},{"key":"e_1_2_12_18_1","doi-asserted-by":"publisher","DOI":"10.1055\/s-0044-1781466"},{"key":"e_1_2_12_19_1","doi-asserted-by":"publisher","DOI":"10.1021\/bi052628y"},{"key":"e_1_2_12_20_1","doi-asserted-by":"publisher","DOI":"10.1038\/nri2155"},{"key":"e_1_2_12_21_1","doi-asserted-by":"publisher","DOI":"10.1182\/blood.2021011849"}],"container-title":["Haemophilia"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/hae.70161","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/full-xml\/10.1111\/hae.70161","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/hae.70161","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T03:55:21Z","timestamp":1790567721000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/hae.70161"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,11,11]]},"references-count":20,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2026,1]]}},"alternative-id":["10.1111\/hae.70161"],"URL":"https:\/\/doi.org\/10.1111\/hae.70161","archive":["Portico"],"relation":{},"ISSN":["1351-8216","1365-2516"],"issn-type":[{"value":"1351-8216","type":"print"},{"value":"1365-2516","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,11,11]]},"assertion":[{"value":"2025-07-11","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-10-24","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-11-11","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}