Interim Analysis of Joint Outcomes in Adult and Adolescent Patients with Severe Hemophilia A Receiving Efanesoctocog Alfa During the Phase 3 XTEND-ed Long-Term Extension Study

A von Drygalski; C Königs; B A Konkle; C Hermans; L Khoo; K Fischer; N Suzuki; H Guo; U Khan; L Bystrická; A Fernandez; E Santagostino; L Mamikonian; R Klamroth

doi:10.1055/s-0044-1801629

Hämostaseologie, Inhaltsverzeichnis

Hamostaseologie 2025; 45(S 01): S55-S56
DOI: 10.1055/s-0044-1801629

Abstracts

Topics

T-07 Hereditary bleeding disorders

Interim Analysis of Joint Outcomes in Adult and Adolescent Patients with Severe Hemophilia A Receiving Efanesoctocog Alfa During the Phase 3 XTEND-ed Long-Term Extension Study

Authors

A von Drygalski

¹University of California, Division of Hematology/Oncology, Department of Medicine, San Diego, USA
C Königs

²Goethe University Frankfurt, University Hospital, Department of Pediatrics and Adolescent Medicine, Frankfurt am Main, Germany
B A Konkle

³Washington Center for Bleeding Disorders and the University of Washington, Seattle, USA
C Hermans

⁴Saint-Luc University Hospital, Université Catholique de Louvain, Division of Haematology, Haemostasis and Thrombosis Unit, Brussels, Belgium
L Khoo

⁵Royal Prince Alfred Hospital, Institute of Haematology, Sydney, Australia
K Fischer

⁶Van Creveldkliniek, University Medical Center Utrecht, Utrecht University, Centre for Benign Haematology, Thrombosis and Haemostasis, Utrecht, Netherlands
N Suzuki

⁷Nagoya University Hospital, Department of Transfusion Medicine, Aichi, Japan
H Guo

⁸Sanofi, Bridgewater, USA
U Khan

⁹Sanofi, Cambridge, USA
L Bystrická

¹⁰Sobi, Basel, Switzerland
A Fernandez

¹¹Sanofi, Zurich, Switzerland
E Santagostino

¹⁰Sobi, Basel, Switzerland
L Mamikonian

⁹Sanofi, Cambridge, USA
R Klamroth

¹²Vivantes Klinikum, Friedrichshain, Berlin, Germany

Abstract

Volltext

Introduction: Hemophilic arthropathy and chronic joint pain from repeated bleeding episodes in hemophilia A may occur despite standard-of-care prophylaxis. In XTEND-1 (NCT04161495), once-weekly efanesoctocog alfa (50 IU/kg) prophylaxis was well tolerated, providing highly effective bleed protection and high-sustained factor VIII activity levels across the weekly dosing interval. The aim is to assess long-term joint health with efanesoctocog alfa prophylaxis in adults/adolescents from XTEND-1 who continued to the extension study, XTEND-ed (NCT04644575).

Method: XTEND-ed is an open-label, multicenter study of previously treated patients with severe hemophilia A. Participants provided informed consent; the study was approved by applicable review boards. Changes from parent study (XTEND-1) baseline to Month 12 in XTEND-ed in Hemophilia Joint Health Scores (HJHS) and target joint resolution for participants aged≥12 years who received once-weekly efanesoctocog alfa (50 IU/kg) prophylaxis are presented descriptively (data cutoff June 8, 2023). Individual joints (left/right elbows, knees, and ankles) were scored according to 8 HJHS domains; gait was also assessed. Total HJHS score encompasses joint and gait score. Target joints were evaluated based on International Society on Thrombosis and Haemostasis criteria.

Results: Arm A of XTEND-ed enrolled 146 participants from XTEND-1 (additional mean [standard deviation, SD] treatment duration 82.5 [14.3] weeks). By Month 12 in XTEND-ed, joint health had improved or been maintained in evaluable participants compared with XTEND-1 baseline, as measured by HJHS total score, total joint score, and subdomain scores ([Fig. 1] [2]). The HJHS domain with the greatest mean (SD) change from baseline to Month 12 was flexion loss -0.6 (2.7). At XTEND-1 baseline, there were 140 target joints among 45 participants; at 1 year, all target joints (n=132) had resolved in participants exposed for≥12 months (n=43).

Fig. 1 Change in HJHS scores for A) total score and B) total joint score from parent study, baseline at end of parent study, and Month 12 in XTEND-ed in participants aged≥12 years

Fig. 2 Mean HJHS subdomain scores at parent study baseline, XTEND-ed baseline, and XTEND-ed Month 12 time points for participants aged≥12 years

Conclusion: Interim results from XTEND-ed indicate that once-weekly prophylaxis with efanesoctocog alfa is associated with improvement or maintenance of joint health in adults and adolescents.

Funded by Sanofi and Sobi.

Abbildungen

Fig. 1 Change in HJHS scores for A) total score and B) total joint score from parent study, baseline at end of parent study, and Month 12 in XTEND-ed in participants aged≥12 years

Fig. 2 Mean HJHS subdomain scores at parent study baseline, XTEND-ed baseline, and XTEND-ed Month 12 time points for participants aged≥12 years