OC 40.4 - Safety and Efficacy of Emicizumab in People with Hemophilia A Enrolled in the Hemophilia Natural History Study (ATHN 7)

Monday, July 11, 2022

3:30 PM – 3:45 PM

Location: ExCel Center, ICC Auditorium

Presentation Format: In-Person

Co-Author(s)

TB

Tyler W. Buckner

Assistant Professor of Medicine
Hemophilia and Thrombosis Center, University of Colorado, School of Medicine
Aurora, California, United States
SL

Shannon L. Carpenter

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

Christine L. Kempton

Associate Professor of Hematology; Regional Director
Hemophilia of Georgia Center for Bleeding and Clotting Disorders of Emory
Atlanta, Georgia, United States
LL

Lucy Lee

Principal Medical Science Director
Genentech, Inc.
South San Francisco, California, United States
Lynn Malec, MD, MSc

Associate Investigator
Versiti Blood Research Institute
Milwaukee, Wisconsin, 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
Michael Wang, MD

HTC Clinical Director
University of Colorado Denver Hemophilia and Thrombosis Center
Aurora, Colorado, United States

Presenting Author(s)

Michael Recht, MD, PhD, MBA

Chief Science Officer
American Thrombosis and Hemostasis Network
Rochester, New York, United States

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

Aims: To report the baseline demographic characteristics of participants and real-world safety and efficacy of emicizumab in ATHN 7.

Methods: ATHN 7 is a longitudinal, prospective observational cohort study being conducted at 26 American Thrombosis and Hemostasis Network (ATHN)-affiliated sites. Ethics approval was obtained and participants and/or parents/guardians provided consent. PwHA receiving care at participating sites are eligible for inclusion. Demographic and clinical information is collected through participant interview and medical record review. Adverse events (AEs) are documented. Here, annualized bleed rates (ABRs) were calculated for PwHA without FVIII inhibitors treated with emicizumab.

Results: As of August 31, 2021, demographic information was available for 249 emicizumab-treated PwHA (Table 1). Baseline inhibitor status was available for 236 individuals (59 with inhibitor, 177 without inhibitor). For the entire cohort, median (range) duration of emicizumab exposure was 77.2 (0.14–141.00) weeks. Fifteen AEs were reported in 9 participants, including 6 injection-site reactions in one participant. There was one death due to hemorrhagic shock, which was deemed unrelated to emicizumab. No thrombotic events or thrombotic microangiopathies were reported. Effectiveness in the PwHA without FVIII inhibitors is summarized in Table 2. Mean (standard deviation) ABRs were 1.30 (2.78) for treated bleeds and 0.73 (2.07) for treated joint bleeds, with similar values for the participants with moderate or severe HA.

Conclusion(s): This is the largest multi-center, prospective observational experience of emicizumab-treated PwHA in the US. No new safety signals were identified and ABRs for PwHA without FVIII inhibitors were consistent across the different severities of HA.