Symington E, Rangarajan S, Lester W, Madan B, Pierce GF, Raheja P, Robinson TM, Osmond D, Russell CB, Vettermann C, Agarwal SK, Li M, Wong WY, Laffan M. Long-term safety and efficacy outcomes of valoctocogene roxaparvovec gene transfer up to 6 years post-treatment.
Haemophilia 2024;
30:320-330. [PMID:
38317480 DOI:
10.1111/hae.14936]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 12/07/2023] [Accepted: 12/30/2023] [Indexed: 02/07/2024]
Abstract
INTRODUCTION
Valoctocogene roxaparvovec uses an adeno-associated virus serotype 5 (AAV5) vector to transfer a factor VIII (FVIII) coding sequence to individuals with severe haemophilia A, providing bleeding protection.
AIM
To assess safety and efficacy of valoctocogene roxaparvovec 5-6 years post-treatment.
METHODS
In a phase 1/2 trial, adult male participants with severe haemophilia A (FVIII ≤1 IU/dL) without FVIII inhibitors or anti-AAV5 antibodies received valoctocogene roxaparvovec and were followed for 6 (6 × 1013 vg/kg; n = 7) and 5 (4 × 1013 vg/kg; n = 6) years. Safety, including investigation of potential associations between a malignancy and gene therapy, and efficacy are reported.
RESULTS
No new treatment-related safety signals emerged. During year 6, a participant in the 6 × 1013 vg/kg cohort was diagnosed with grade 2 parotid gland acinar cell carcinoma; definitive treatment was uncomplicated parotidectomy with lymph node dissection. Target enrichment sequencing of tumour and adjacent healthy tissue revealed low vector integration (8.25 × 10-5 per diploid cell). Integrations were not elevated in tumour samples, no insertions appeared to drive tumorigenesis, and no clonal expansion of integration-containing cells occurred. During all follow-ups, >90% decreases from baseline in annualised treated bleeds and FVIII infusion rates were maintained. At the end of years 6 and 5, mean FVIII activity (chromogenic assay) was 9.8 IU/dL (median, 5.6 IU/dL) and 7.6 IU/dL (median, 7.1 IU/dL) for the 6 × 1013 and 4 × 1013 vg/kg cohorts, respectively, representing proportionally smaller year-over-year declines than earlier timepoints.
CONCLUSIONS
Valoctocogene roxaparvovec safety and efficacy profiles remain largely unchanged; genomic investigations showed no association with a parotid tumour.
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