PB0233 - Assessing factor consumption and bleeding outcomes of prophylaxis with three commonly prescribed factor IX products for hemophilia B: a retrospective medical chart analysis in the United States

Sunday, June 23, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Co-Author(s)

Miguel Escobar, MD

Professor of Medicine and Pediatrics
University of Texas Health Science Center of Houston, McGovern Medical School, Gulf States Hemophilia and Thrombophilia Center, Houston, Texas
Houston, Texas, United States

Presenting Author(s)

SY

Songkai Yan

Director, Global Evidence, Market Access and Pricing
CSL Behring, King of Prussia, PA, USA
King of Prussia, Pennsylvania, United States

Co-Author(s)

YY

Ying Yang

Senior consultant
Adivo Associates LLC, CA, USA
San Francisco, California, United States
DD

Douglass Drelich

Assoc Director, Global Medical Affairs Hematology
CSL Behring, King of Prussia, PA, USA
King of Prussia, Pennsylvania, United States
XZ

Xiang Zhang

Director, Medical Affairs Biostatistics Quantitative Clinical Sciences and Reporting
CSL Behring, King of Prussia, PA, USA
King of Prussia, Pennsylvania, United States
GK

Gbenga Kayode

Associate Director, Clinical Epidemiology
CSL Behring, King of Prussia, PA, USA
King of Prussia, Pennsylvania, United States
MJ

Mariama Jabati

Associate Consultant
Adivo Associates LLC, San Francisco, CA, USA
San Francisco, California, United States
MS

Mindy Simpson

Medical Director
Rush Hemophilia and Thrombophilia Center, Rush University Medical Center, Chicago, IL, USA
Chicago, Illinois, United States

Background: In the United States (US), rIX-FP, rFIXFc and rFIX are approved for the treatment of people with hemophilia B (PwHB). While clinical trials have demonstrated the efficacy and safety of each product, real-world data can help to understand their consumption and the treatment outcome in the absence of direct head-to-head trials.

Aims: To assess real-world FIX consumption and bleeding outcomes for PwHB receiving rIX-FP, rFIXFc or rFIX prophylaxis aged ≥12 years.

Methods: De-identified medical chart information for PwHB with severe or moderate hemophilia B (FIX activity ≤5%) treated with at least 12 months of prophylaxis were retrospectively obtained from US hemophilia treatment centers between 2020–2023. FIX consumption was calculated using the most recent prescribed dosing frequency and dosage. Annualized bleeding rate (ABR), annualized spontaneous bleeding rate (AsBR) and annualized joint bleeding rate (AjBR) were calculated based on the number of bleeding events over the observation period. Generalized linear models adjusting for covariates were used to test statistical significance of the differences of consumption and ABR between the products.

Results: Overall, 213 PwHB (53% with severe HB) were included, with a mean age [range] of 32.7 [12-84] years (Table 1). Results for consumption and bleeding rates are presented in Table 2. PwHB treated with rIX-FP prophylaxis had significantly lower mean FIX consumption compared to those treated with the other two products: rIX-FP (45.8 IU/kg/week) vs. rFIXFc (65.4 IU/kg/week, p=0.0003); vs. rFIX (95.7 IU/kg/week, p< 0.0001). Mean ABR was significantly lower for rIX-FP prophylaxis (1.2) vs. rFIXFc (2.1; p=0.0119) and rFIX (2.3; p=0.004). Mean AsBR was rIX-FP (0.4), rFIXFc (1.0) and rFIX (0.7), respectively. Mean AjBR was rIX-FP (0.7), rFIXFc (1.1) and rFIX (1.2), respectively.

Conclusion(s): Results suggest that rIX-FP prophylaxis was associated with lower FIX consumption and improved bleed protection compared with rFIXFc and rFIX treatments.