To perform a liver biopsy in haemophilia A and B patients with endogenous FVIII:C/FIX:C expression at \>1% any time after gene transfer following AAV mediated gene transfer. This is to obtain tissue for analysis, to understand if FIX/FVIII transgenic protein expression is mediated by AAV proviral DNA that is integrated into the host cell DNA or if stable expression in humans is mediated by episomal maintained AAV genome.
To better understand the consequences of AAV gene transfer patients will be recruited to undergo a liver biopsy. Patients will have endogenous FVIII:C/FIX:C expression at \>1% any time after gene transfer following AAV mediated gene transfer. Analysis of biopsy samples will: * Provide a clearer insight into the AAV life cycle in human liver * Define the number of human hepatocytes that are transduced * Improve understanding at the human hepatocyte level of long-term consequences of AAV mediated transgene expression from the liver that will include (i) changes in the pattern of gene expression in human hepatocytes following AAV mediated gene transfer, (ii) information on the epigenetic signature in the liver following AAV mediated gene transfer and how this changes with time and (iii) the consequences of transgene expression in hepatocytes. This study will provide new data addressing several unknowns with AAV mediated gene transfer in humans that will better inform on safety and efficacy following AAV gene transfer for patients who have already participated in gene therapy studies as well as those considering this treatment option.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
10
The study population is patients with either haemophilia A or B who have previously been administered gene therapy treatment in one of three specific gene therapy clinical trials. In this study they will have a liver biopsy performed to take up to 3 samples for laboratory analysis.
Royal Free Hospital
London, United Kingdom
RECRUITINGAnalysis of AAV integration in hepatocytes using Target Enrichment Sequencing
The determination of AAV integration sites will be performed for each participant using Target Enrichment Sequencing (TES) analysis of their liver biopsy sample. This will identify DNA sequences flanking the vector genome. The sequencing data will be analyzed to determine 1. Vector-Vector Concatemers and Vector-Genome Junctions Analysis 2. Integration Site,read count, genomic position and nearest gene
Time frame: Biopsy samples will be taken from participants who are between one month and up to 15 years post gene therapy
Histology analysis using hematoxylin and eosin staining and immunohistochemical staining to determine histopathological changes in hepatocytes
Hematoxylin and eosin staining and immunohistochemical staining will be done on a liver biopsy sample from each participant to provide information about the structure and distribution of cells and any morphological changes within the liver biopsy sample.
Time frame: Biopsy samples will be taken from participants who are between one month and up to 15 years post gene therapy
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