Plenary Poster ESA-SRB-ANZBMS 2024 in conjunction with ENSA

Real-world characteristics and disease history of patients with x-linked hypophosphatemia treated with burosumab: a United States claims database study (#306)

Kathryn Dahir 1 , Heather Heerssen 2 , Yang Zhao 2 , Angie Dale 2 , Ahmed Noman 3 , Zhiyi Li 2 , Ki Hyon Kim 4 , Tiffany Bamford 5
  1. Vanderbilt University Medical Center, Nashville, USA
  2. Kyowa Kirin, Inc., Princeton, USA
  3. Komodo Health, New York, USA
  4. Kyowa Kirin Asia Pacific Ptd Ltd, Singapore
  5. Kyowa Kirin Australia, Sydney, Australia

Aims: X-linked hypophosphatemia (XLH) is a rare genetic disease characterized by chronic renal phosphate wasting. In 2018, burosumab became the first US FDA-approved therapy for targeted treatment of XLH. This study examined patient characteristics and disease history among real-world patients with XLH initiating burosumab in the US.

 Methods: This retrospective cohort study used Komodo Health’s Healthcare Map™, a real-world de-identified patient-level claims database. Patients had ≥1 claim for familial hypophosphatemia between 01/01/2015 and 06/30/2022 and ≥1 claim for burosumab between 04/01/2018 and 06/30/2022 (index date was the date of first burosumab claim). The study period was the period prior to the index date, ranging 1-7 years. Patient characteristics were measured at index and disease history was measured over the study period and stratified by age; all variables were evaluated descriptively.

 Results: 1358 patients were included (mean age 23.5 ± 19.1 years, 62% female, 41% from the southern US). Approximately half (53%) of XLH patients were <18 years at initiation of burosumab. Prior to receiving burosumab, patients had high levels of XLH-related morbidities, which appeared early and increased with age group (Figure). Most patients received conventional therapy for XLH during the study period, including high-dose calcitriol (66% and 56% of patients <18 years and ≥18 years, respectively) and/or phosphate supplements (42% and 44% of patients <18 years and ≥18 years, respectively), prior to burosumab. Opioid use was prevalent among XLH patients prior to burosumab treatment (24% and 51% of patients <18 years and ≥18 years, respectively). Physical therapy use was observed across age groups (18% and 40% of patients <18 years and ≥18 years, respectively).

 Conclusions:  At the time of burosumab initiation, approximately half of patients with XLH were <18 years of age and had experienced a heavy and progressive disease burden. The prevalence of XLH-related morbidities increased with age.

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