Completion of phase 2b trial of etranacogene dezaparvovec gene therapy in patients with hemophilia B over 5 years
Abstract: Etranacogene dezaparvovec (CSL222, formerly AMT-061) is a recombinant adeno-associated virus serotype 5 (AAV5) vector containing the highly active factor IX (FIX) Padua variant controlled by a liver-specific promoter. This phase 2b, open-label, single-dose, single-arm, multicenter trial ev...
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| Format: | Article |
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Elsevier
2025-07-01
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| Series: | Blood Advances |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2473952925002022 |
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| author | Annette von Drygalski Esteban Gomez Adam Giermasz Giancarlo Castaman Nigel S. Key Susan U. Lattimore Frank W. G. Leebeek Wolfgang A. Miesbach Michael Recht Paul E. Monahan Sandra Le Quellec Steven W. Pipe |
| author_facet | Annette von Drygalski Esteban Gomez Adam Giermasz Giancarlo Castaman Nigel S. Key Susan U. Lattimore Frank W. G. Leebeek Wolfgang A. Miesbach Michael Recht Paul E. Monahan Sandra Le Quellec Steven W. Pipe |
| author_sort | Annette von Drygalski |
| collection | DOAJ |
| description | Abstract: Etranacogene dezaparvovec (CSL222, formerly AMT-061) is a recombinant adeno-associated virus serotype 5 (AAV5) vector containing the highly active factor IX (FIX) Padua variant controlled by a liver-specific promoter. This phase 2b, open-label, single-dose, single-arm, multicenter trial evaluated the efficacy and safety of etranacogene dezaparvovec. Three adult participants with severe or moderately severe hemophilia B (FIX ≤2%) and AAV5-neutralizing antibodies received a single IV dose (2 × 1013 genome copies per kg) of etranacogene dezaparvovec. The primary end point of FIX activity ≥5 IU/dL at 6 weeks was met (mean, 30.6 IU/dL). Secondary end points included bleed frequency, FIX concentrate use, and adverse events. Here, we report the end-of-study 5-year outcomes. After administration, mean (range) FIX activity increased to 40.8 IU/dL (31.3-50.2) at year 1 and was maintained at 45.7 IU/dL (39.0-51.2) at year 5. Mean annualized bleeding rate (all bleeds) was 0.14 for the cumulative follow-up period years 0 to 5. Two participants had 5 bleed-free years after treatment. Per protocol, 1 participant received episodic FIX replacement therapy after treatment for elective surgeries, 2 bleeding episodes, and 2 single self-administered infusions for unreported reasons. All participants discontinued and remained free of FIX prophylaxis. During the 5-year study period, there were no clinically significant elevations in liver enzymes, requirement for steroids, FIX inhibitor development, thrombotic complications, or late-emergent safety events in any participant. Five years after administration, etranacogene dezaparvovec was effective in adults with hemophilia B with a favorable safety profile. Participants are eligible to participate in an extension study (ClinicalTrials.gov identifier: NCT05962398) for 10-year additional follow-up. This trial was registered at www.clinicaltrials.gov as #NCT03489291. |
| format | Article |
| id | doaj-art-017ca7f3bc1e48959192c6f23df0f8ae |
| institution | DOAJ |
| issn | 2473-9529 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Blood Advances |
| spelling | doaj-art-017ca7f3bc1e48959192c6f23df0f8ae2025-08-20T03:12:56ZengElsevierBlood Advances2473-95292025-07-019143543355210.1182/bloodadvances.2024015291Completion of phase 2b trial of etranacogene dezaparvovec gene therapy in patients with hemophilia B over 5 yearsAnnette von Drygalski0Esteban Gomez1Adam Giermasz2Giancarlo Castaman3Nigel S. Key4Susan U. Lattimore5Frank W. G. Leebeek6Wolfgang A. Miesbach7Michael Recht8Paul E. Monahan9Sandra Le Quellec10Steven W. Pipe11Division of Hematology/Oncology, Department of Medicine, University of California San Diego, San Diego, CA; Correspondence: Annette von Drygalski, Division of Hematology/Oncology, Department of Medicine, University of California San Diego, 9333 Genesee Ave, Suite 310, San Diego, CA 92121;Center for Inherited Blood Disorders, Orange, CADivision of Hematology/Oncology, Department of Medicine, Hemophilia Treatment Center, University of California Davis, Sacramento, CACenter for Bleeding Disorders, Department of Oncology, Careggi University Hospital, Florence, ItalyDivision of Hematology and Blood Research Center, Department of Medicine, University of North Carolina, Chapel Hill, NCDepartment of Pediatrics, The Hemostasis and Thrombosis Center, Oregon Health & Science University, Portland, ORDepartment of Hematology, Erasmus Medical Centre, University Medical Center, Rotterdam, The NetherlandsDepartment of Hemostaseology and Hemophilia Center, Medical Clinic 2, Institute of Transfusion Medicine, University Hospital Frankfurt, Frankfurt, GermanyNational Bleeding Disorders Foundation, New York, NY; Division of Pediatric Hematology-Oncology, Center for Bleeding and Clotting Disorders, Yale School of Medicine, New Haven, CTHematology Clinical Development, CSL Behring, King of Prussia, PAHematology Clinical Development, CSL Behring, King of Prussia, PADepartments of Pediatrics and Pathology, University of Michigan, Ann Arbor, MIAbstract: Etranacogene dezaparvovec (CSL222, formerly AMT-061) is a recombinant adeno-associated virus serotype 5 (AAV5) vector containing the highly active factor IX (FIX) Padua variant controlled by a liver-specific promoter. This phase 2b, open-label, single-dose, single-arm, multicenter trial evaluated the efficacy and safety of etranacogene dezaparvovec. Three adult participants with severe or moderately severe hemophilia B (FIX ≤2%) and AAV5-neutralizing antibodies received a single IV dose (2 × 1013 genome copies per kg) of etranacogene dezaparvovec. The primary end point of FIX activity ≥5 IU/dL at 6 weeks was met (mean, 30.6 IU/dL). Secondary end points included bleed frequency, FIX concentrate use, and adverse events. Here, we report the end-of-study 5-year outcomes. After administration, mean (range) FIX activity increased to 40.8 IU/dL (31.3-50.2) at year 1 and was maintained at 45.7 IU/dL (39.0-51.2) at year 5. Mean annualized bleeding rate (all bleeds) was 0.14 for the cumulative follow-up period years 0 to 5. Two participants had 5 bleed-free years after treatment. Per protocol, 1 participant received episodic FIX replacement therapy after treatment for elective surgeries, 2 bleeding episodes, and 2 single self-administered infusions for unreported reasons. All participants discontinued and remained free of FIX prophylaxis. During the 5-year study period, there were no clinically significant elevations in liver enzymes, requirement for steroids, FIX inhibitor development, thrombotic complications, or late-emergent safety events in any participant. Five years after administration, etranacogene dezaparvovec was effective in adults with hemophilia B with a favorable safety profile. Participants are eligible to participate in an extension study (ClinicalTrials.gov identifier: NCT05962398) for 10-year additional follow-up. This trial was registered at www.clinicaltrials.gov as #NCT03489291.http://www.sciencedirect.com/science/article/pii/S2473952925002022 |
| spellingShingle | Annette von Drygalski Esteban Gomez Adam Giermasz Giancarlo Castaman Nigel S. Key Susan U. Lattimore Frank W. G. Leebeek Wolfgang A. Miesbach Michael Recht Paul E. Monahan Sandra Le Quellec Steven W. Pipe Completion of phase 2b trial of etranacogene dezaparvovec gene therapy in patients with hemophilia B over 5 years Blood Advances |
| title | Completion of phase 2b trial of etranacogene dezaparvovec gene therapy in patients with hemophilia B over 5 years |
| title_full | Completion of phase 2b trial of etranacogene dezaparvovec gene therapy in patients with hemophilia B over 5 years |
| title_fullStr | Completion of phase 2b trial of etranacogene dezaparvovec gene therapy in patients with hemophilia B over 5 years |
| title_full_unstemmed | Completion of phase 2b trial of etranacogene dezaparvovec gene therapy in patients with hemophilia B over 5 years |
| title_short | Completion of phase 2b trial of etranacogene dezaparvovec gene therapy in patients with hemophilia B over 5 years |
| title_sort | completion of phase 2b trial of etranacogene dezaparvovec gene therapy in patients with hemophilia b over 5 years |
| url | http://www.sciencedirect.com/science/article/pii/S2473952925002022 |
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