OC 40.4 - Concizumab efficacy results at 56-week cut-off in patients with hemophilia A/B without inhibitors: an intra-patient analysis from the phase 3 explorer8 study

Monday, June 24, 2024

15:30 – 15:45 ICT

Room: Plenary Hall

Presenting Author(s)

Anthony KC Chan, MBBS

Professor
McMaster Children’s Hospital, McMaster University, Hamilton, Canada
Hamilton, Ontario, Canada

Co-Author(s)

Pratima Chowdary, MD

Professor of Haemophilia, Centre Director
Katharine Dormandy Haemophilia and Thrombosis Centre, Royal Free Hospital
London, England, United Kingdom
Hermann Eichler

Physician
Institute of Clinical Hemostaseology and Transfusion Medicine, Saarland University and University Hospital, Homburg, Germany
Homburg/Saar, Saarland, Germany
AR

Amalie Rhode Høgh Nielsen

Senior Statistician
Novo Nordisk A/S, Søborg, Denmark
Søborg, Hovedstaden, Denmark
JT

Jay Jay Thaung Zaw

Senior International Medical Manager
Novo Nordisk A/S, Søborg, Denmark
Søborg, Hovedstaden, Denmark
Guy Young, MD

Director, Hemostasis and Thrombosis Program
Children's Hospital of Los Angeles, Los Angeles, USA
Los Angeles, California, United States
Pantep Angchaisuksiri

Professor of Medicine and Chief of the Haemostasis and Thrombosis Unit
Department of Medicine, Ramathibodi Hospital, Mahidol University
Bangkok, Krung Thep, Thailand

Background: Concizumab is an anti-tissue factor pathway inhibitor (TFPI) monoclonal antibody in development as a once-daily subcutaneous prophylaxis for patients with hemophilia A/B (HA/HB) with and without inhibitors. Intra-patient efficacy of concizumab compared with previous prophylaxis was evaluated in a subset of patients; confirmatory analysis results have been reported (Chowdary P, OC59.1. RPTH. 2023:7[Suppl 2]).

Aims: To present descriptive statistics of efficacy at the 56-week cut-off for a subset of patients with HA/HB without inhibitors on concizumab prophylaxis in explorer8 (NCT04082429), and descriptive statistics for the same patients while on stable factor prophylaxis in a prior non-interventional study (explorer6; NCT03741881).

Methods: Male patients (≥12 years) were assigned to one of four arms in explorer8. Descriptive statistics on the number of treated spontaneous and traumatic bleeding episodes at the 56-week data cut-off were assessed in a subset of patients receiving concizumab in a non-randomized arm of explorer8 and also in the same patients while previously on stable factor prophylaxis for ≥24 weeks in explorer6. Stable factor prophylaxis was defined as the time after an initial period on prophylaxis of ≥24 weeks. The 56-week cut-off was defined as when all patients in concizumab arms had completed their 56-week visit or permanently discontinued treatment.

Results: Descriptive assessments for treated spontaneous and traumatic bleeding episodes are presented by hemophilia subtype (Table 1): for patients with HA, median annualized bleeding rate (ABR) (interquartile range [IQR]) was 2.2 (0.8–6.2) on previous factor prophylaxis and 1.7 (0.5–4.8) on concizumab at the 56-week cut-off; for patients with HB, median ABR (IQR) was 2.1 (0.9–4.2) on previous prophylaxis and 1.3 (0.0–6.4) on concizumab at the 56-week cut-off.

Conclusion(s): Low median ABRs for treated spontaneous and traumatic bleeding episodes were maintained at the 56-week cut-off, consistent with 32-week cut-off results, in patients with HA/HB without inhibitors, previously on stable factor prophylaxis.