Background: Emicizumab, a recombinant humanized bispecific antibody that binds FIXa/FX and mimics FVIII cofactor function, is a novel agent FDA-approved for prophylaxis in hemophilia A (HA) with/without inhibitors. Despite reassuring safety/efficacy clinical trial data, real world data is limited.

Aims: We report single-center, post-licensure experience in 122 moderate/severe HA patients treated with emicizumab for >6 months; 25 surgeries were performed in 22 patients.

Methods: A post-licensure retrospective observational analysis was performed to assess safety/efficacy in HA on emicizumab between 10/08/2018-12/31/2019; patients in HAVEN studies were excluded. The EMR was queried for moderate/severe HA on emicizumab for >6 months and HA on emicizumab for any duration who underwent surgery.

Results: 122 patients [1-66yrs, median 16] received emicizumab for >6 months; 35 patients[28.7%] were < 12yrs
[1-11yrs; median 5]; 88[72.1%] were >12yrs [12-66yrs; median 21]; 7[5.7%] with inhibitors [3-23yrs; median 6], 115[94.3%] without inhibitors [1-66yrs; median 17]. Twenty-five surgeries were performed in 22 patients
[2-66yrs;median 15] with 5 procedures in 4 inhibitor patients [18.2%;median 5.5yrs].
During emicizumab prophylaxis, 128 bleeding events occurred in 60/122(49.2%) patients [13/35(37.1%) < 12 yrs and 47/87(54%) patients >12 yrs]; 62(50.8%) patients had 0 treated bleeds. Perioperative bleeding occurred in 8/25 (32%) surgeries. Additional perioperative hemostatic agents were used in 20(80%) surgeries; fewer bleeds occurred with pre/intraoperative hemostatic therapy (3/15; 20%) vs. emicizumab as sole hemostatic agent (5/10; 50%).

Conclusions: These data represent real world use of emicizumab in a large population with HA. Confounding factors affecting bleeding rates include: differentiating bleeds from arthropathy, pre-emptive treatment after injury and prior to hemostatic challenges. Patients may not report treating suspected bleeds/injuries.
No thrombosis/thrombotic microangiopathy or deaths occurred. We observed effective bleed control on emicizumab and safety with additional hemostatic agent use in surgery. With further experience, we expect a decrease in postoperative bleeding. These results add to reported study data on safety/efficacy of emicizumab.

[Moderate/severe HA treated with emicizumab > 6 months]

[Moderate/severe HA treated with emicizumab > 6 months]

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ISTH Congress Abstracts - https://abstracts.isth.org/abstract/real-world-experience-with-emicizumab-in-persons-with-hemophilia-a-ha-with-or-without-inhibitors/