Abstract Number: PB0907
Meeting: ISTH 2020 Congress
Background: Frequent infusions and bleeding can substantially affect the quality of life of hemophilia B (HB) patients. PROLONG 9FP clinical trials demonstrated that rIX-FP, a recombinant long acting FIX, allows a prophylaxis with extended dosing intervals that is effective in bleeding control and prevention.
Aims: Here we report two cases of young patients with severe HB switching from standard- rFIX to rIX-FP.
Methods: In August 2017, two brothers were switched from rFIX (40 IU/kg twice weekly) to rIX-FP. Doses were adjusted to extend the dosing interval while maintaining FIX levels >5%. FIX activity was measured at defined time points after a single infusion of 50 IU/kg rIX-FP following a 7-day washout period. Breakthrough bleeding, joint bleeding and inhibitors development were monitored. Physical activity was assessed before and after the switch.
Results: Fifteen minutes after the infusion, FIX activity levels were 110% in patient 1 (11 years old) and 89.4% in patient 2 (8 years old). At day 7, FIX levels were >10% for both patients. On day 10, patients 1 and 2 maintained the FIX activity at 6.13% and 5.46%, respectively. Consequently, they were prescribed 43 IU/kg and 50 IU/kg rIX-FP every 10 days, respectively. Since switching to rIX-FP prophylaxis, in any case neither breakthrough bleeding, nor inhibitors, nor joint involvements have been observed. Patients considerably increased their physical activity at school, becoming regularly involved in gym (2-3 times/week) plus motor activities (2 times/week). No inhibitors have been observed in either case, and patient 1 learned to self-infuse.
Conclusions: In two young patients with severe HB, an extended 10-day rIX-FP dosing was well tolerated, allowed FIX levels >5%, provided effective bleeding prevention and a substantial reduction in FIX consumption. Moreover, switching to rIX-FP increased the treatment satisfaction and improved the compliance both in patients and in their caregivers.
To cite this abstract in AMA style:Sottilotta G, Luise F, Nicolò GM, Oriana V, Piromalli A. Favourable Outcomes in Two Young Patients with Severe Haemophilia B After Switching to rIX-FP [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/favourable-outcomes-in-two-young-patients-with-severe-haemophilia-b-after-switching-to-rix-fp/. Accessed November 30, 2021.
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