Clinical Outcomes in Adults With Hemophilia B With and Without Pre-existing Neutralizing Antibodies to AAV5: 6 Month Data From the Phase 3 Etranacogene Dezaparvovec HOPE-B Gene Therapy Trial

Highlights From the ISTH 2021 Congress

Clinical Outcomes in Adults With Hemophilia B With and Without Pre-existing Neutralizing Antibodies to AAV5: 6 Month Data From the Phase 3 Etranacogene Dezaparvovec HOPE-B Gene Therapy Trial

F.W. Leebeek¹, W. Miesbach², M. Recht³, N.S Key⁴, S. Lattimore³, G. Castaman⁵, E.K Sawyer^6,7, D. Cooper^6,7, V. Ferriera^6,7, S.W Pipe⁸, HOPE-B Investigators

¹Erasmus University Medical Center, Rotterdam, Netherlands

²University Hospital Frankfurt, Frankfurt, Germany

³Oregon Health & Science University, Portland, United States

University of North Carolina, Chapel Hill, United States

⁵Center for Bleeding Disorders and Coagulation, Careggi University Hospital, Florence, Italy

⁶uniQure BV, Amsterdam, Netherlands

⁷uniQure Inc, Lexington, United States

⁸University of Michigan, Ann Arbor, United States

Key Data Points

FIX Activity in Patients With and Without AAV5 Neutralizing Antibodies
Adverse Events From the HOPE-B Trial

FIX Activity in Patients With and Without AAV5 Neutralizing Antibodies

In the HOPE-B trial, 23 of 54 initial participants had detectable neutralizing AAV5 antibody (Nabs) titers at baseline, and it was possible to evaluate results for correlation between NAbs and FIX activity. The vertical axis is the observed 6 month FIX activity of those who received a full dose of vector. Patients with undetectable NAbs were plotted at 7 on the horizontal axis (the threshold of the assay). The horizontal axis shows the titers of the other participants over a range of 7–700. There was one nonresponding participant who had a titer > 3200, which is not included. As shown in the graph, FIX activity was similar in participants with and without pre-existing NAbs to AAV5 up to a titer of 678.

This table from the HOPE-B trial shows adverse events following transgene infusion for patients with (n = 23) and without (n = 31) detectable AAV5 neutralizing antibodies (NAbs) at baseline. As with the levels of FIX, there was no obvious difference in AEs for patients with and without AAV5 NAbs.