PB0205 - Long-term safety and effectiveness of emicizumab in people with hemophilia A in the Hemophilia Natural History Study (ATHN 7)

Sunday, June 23, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Presenting Author(s)

Michael Recht, MD, PhD, MBA

Chief Medical and Science Officer
National Bleeding Disorders Foundation
Charlestown, Rhode Island, United States

Co-Author(s)

SC

Shannon L. Carpenter

Professor of Pediatrics, Associate Division Director, Section of Hematology; Director
Kansas City Regional Hemophilia Center
Kansas City, Missouri, United States
LL

Lucy Lee

Senior Principal Medical Science Director
Genentech, Inc.
South San Francisco, California, United States
TM

Thomas W. McLean

Professor of Pediatric Hematology/Oncology; Director
Wake Forest University Health Sciences
Winston-Salem, North Carolina, United States
PM

Paul Morton

Principal Data Scientist
Genentech, Inc.
South San Francisco, California, United States
JS

Janice M. Staber

Assistant Professor of Pediatrics Hematology/Oncology
Iowa Hemophilia and Thrombosis Center – University of Iowa
Iowa City, Iowa, United States
MW

Michael Wang

HTC Clinical Director; Professor of Pediatrics Hematology/Oncology
University of Colorado School of Medicine
Aurora, Colorado, United States
Tammuella Chrisentery-Singleton, MD

Chief Science Officer (ATHN)
American Thrombosis and Hemostasis Network
New Orleans , Louisiana, United States

Background: Emicizumab, a bispecific monoclonal antibody that bridges activated factor (F)IX and FX, substitutes for a deficiency of FVIII in people with hemophilia A (PwHA). ATHN 7, A Natural History Study of the Safety, Effectiveness, and Practice of Treatment for People with Hemophilia (NCT03619863), monitors the real-world use of current hemophilia treatments, including emicizumab.

Aims: To report long-term data on real-world safety/effectiveness of emicizumab in ATHN 7.

Methods: ATHN 7 is a prospective observational study conducted at 26 American Thrombosis and Hemostasis Network (ATHN)-affiliated sites in the US (supported in part by Genentech, Inc). Ethics approval and consent were obtained. PwHA at participating sites were eligible. Demographic and clinical information was collected through interview and medical record review. Adverse events (AEs) were documented and annualized bleeding rates (ABRs) were calculated.

Results: As of August 31, 2023, demographic information was available for 257 participants treated with emicizumab (Table 1). The median duration of exposure was 118 (range: 13–207) weeks. At baseline, 63 (24.5%) participants had FVIII inhibitors and 191 (74.3%) did not (unknown for 3 [1.2%]). Two (0.8%) participants had mild, 38 (14.8%) had moderate, and 217 (84.4%) had severe HA. Fifteen participants reported 42 AEs, including 34 injection-site reactions in seven participants. There was one death, due to hemorrhagic shock, deemed unrelated to emicizumab (previously reported). No thromboembolic events or thrombotic microangiopathies occurred. Mean (standard deviation) ABRs for treated bleeds and treated joint bleeds were 1.23 (1.97) and 0.75 (1.60), respectively, in participants without inhibitors. They were 1.03 (1.79) and 0.59 (1.25), respectively, in participants with inhibitors (Table 2).

Conclusion(s): This is the largest multi-center, prospective, observational experience for PwHA treated with emicizumab in the USA. No new safety signals were identified; effectiveness was consistent across hemophilia severities and between participants with or without inhibitors. The benefit–risk ratio of emicizumab remains positive.