scholarly journals Long-Term AAV-Mediated Factor VIII Expression in Nine Hemophilia A Dogs: A 10 Year Follow-up Analysis on Durability, Safety and Vector Integration

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 611-611 ◽  
Author(s):  
Giang N. Nguyen ◽  
John K. Everett ◽  
Hayley Raymond ◽  
Samita Kafle ◽  
Elizabeth P. Merricks ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Liver Function ◽  
Factor Viii ◽  
Copy Number ◽  
Hemophilia A ◽  
Clonal Expansion ◽  
Clotting Factor ◽  
Single Chain

Hemophilia is an X-linked bleeding disorder caused by a deficiency in clotting factor VIII (FVIII)(hemophilia A, HA) or factor IX (FIX)(hemophilia B, HB). While early clinical trials of AAV delivery of FIX for HB have demonstrated stable FIX expression for >8 years, an ongoing clinical trial of AAV-FVIII delivery for HA achieved high levels of transgene expression that unexpectedly declined after 1 year. Here we describe preclinical studies of AAV-canine FVIII (cFVIII) delivery in nine HA dogs with sustained FVIII expression for the duration of the study, as long as 10 years. FVIII was delivered using two delivery approaches: (1) co-administration of two AAV vectors encoding separate cFVIII heavy and light chains driven by the thyroxine binding globulin (TBG) promoter (Two chain approach)(TC) (n=5) at two AAV doses (2.5 x 1013vg/kg; F24, Woodstock, J60) and (1.2 x 1013vg/kg; Linus, H19) or (2) delivery of cFVIII as a single chain driven by the human alpha-1 anti-trypsin (hAAT) promoter (Single chain approach)(SC)(n=4) at two AAV doses (4 x 1013 vg/kg; M50, M06) and (2 x 1013vg/kg; M66, L51) (Sabatino 2011). We demonstrated that both strategies were efficacious; preventing >95% of spontaneous bleeding episodes without toxicity. We now report the long-term follow-up of between 2.2 and 10.1 years for these treated dogs. Dose-dependent cFVIII:C (Coatest SP4 FVIII) was observed. At the final time point, the cFVIII:C was 2.7% (F24), 7.1% (Woodstock), 4.5% (J60), 11.3% (Linus) and 2.5% (H19) for TC dogs. For the SC dogs, the cFVIII:C was 9.4% (M06), 10.3% (M50), 1.9% (L51) and 3.7% (M66). Stable FVIII expression was maintained for seven of the dogs over the course of the study. Two dogs (Linus, M50) had a gradual increase in FVIII:C that began about three years after vector administration and continued for an additional seven years (Linus) and four years (M50), until the termination of the study. Liver function tests, serum alpha-fetoprotein concentrations, fibrinogen levels as well as liver pathology did not suggest altered liver function or tumor development in Linus and M50 compared to the other dogs. Clinically, there was no evidence of malignancy and no tumors were detected at the time of necropsy in any dog. One of the safety concerns for AAV-mediated gene therapy approaches is the potential for AAV integration events to be genotoxic and lead to tumorigenesis. While recombinant AAV primarily remains as an episome, integration events have been observed in mouse models and hepatocellular carcinoma has been observed after neonatal delivery of AAV vectors. In addition, the increase in FVIII expression in Linus and M50 prompted us to investigate integration and clonal expansion as a potential mechanism for these observations. Vector copy number (VCN) analysis was performed on liver samples (5-29 per dog, n=8 dogs) by Q-PCR and detected DNA copy numbers between 0.0 and 7.8 per diploid genome (Fig 1A). We performed integration target site analysis on liver samples (n=3/dog) from six of the AAV-treated HA dogs and naïve HA dogs (n=2) by ligation-mediated PCR, Ilumina paired-end sequencing and analysis using the custom software pipeline, AAVenger. Analysis of the 20 samples identified >2,000 unique AAV integration events (IE). There was a correlation between the DNA copy number and the number of integration events detected. Clonal abundances were estimated by counting the unique genome breaks associated with integration positions, which showed that the maximum clonal abundance ranged from 1 to 138. The integration events were distributed across the canine genome. Clonal expansions were observed with integration near genes previously associated with growth control and transformation in humans (Fig 1B) with the most abundant clones located in DLEU2L (Linus), PEBP4 (J60) and EGR3 (M50). Integration events in EGR3, EGR2, CCND1, LTO1 and ZNF365 were detected in multiple dogs. Validation of integration sites in the most abundant clones was performed using targeted PCR to isolate junction fragments followed by Sanger sequencing. While AAV integration and clonal expansion was observed, the dogs had no evidence for tumorigenesis and it is not clear if the increase in FVIII expression is associated with the clonal expansions detected. Overall, these studies demonstrate long-term sustained FVIII expression for up to 10 years with clonal expansion, but without clinical adverse events after AAV-mediated gene therapy for hemophilia. Disclosures Sabatino: Spark Therapeutics: Patents & Royalties.

Animal Testing of Retroviral-Mediated Gene Therapy for Factor VIII Deficiency

1999 ◽  
Vol 82 (08) ◽  
pp. 555-561 ◽  
Author(s):  
Douglas Jolly ◽  
Judith Greengard
Keyword(s):  
Gene Therapy ◽  
Factor Viii ◽  
Hemophilia A ◽  
Joint Damage ◽  
Coagulation Factor ◽  
The United States ◽  
Severe Hemophilia ◽  
Factor Viii Gene ◽  
Bleeding Episodes

IntroductionHemophilia A results from the plasma deficiency of factor VIII, a gene carried on the X chromosome. Bleeding results from a lack of coagulation factor VIII, a large and complex protein that circulates in complex with its carrier, von Willebrand factor (vWF).1 Severe hemophilia A (<1% of normal circulating levels) is associated with a high degree of mortality, due to spontaneous and trauma-induced, life-threatening and crippling bleeding episodes.2 Current treatment in the United States consists of infusion of plasma-derived or recombinant factor VIII in response to bleeding episodes.3 Such treatment fails to prevent cumulative joint damage, a major cause of hemophilia-associated morbidity.4 Availability of prophylactic treatment, which would reduce the number and severity of bleeding episodes and, consequently, would limit such joint damage, is limited by cost and the problems associated with repeated venous access. Other problems are associated with frequent replacement treatment, including the dangers of transmission of blood-borne infections derived from plasma used as a source of factor VIII or tissue culture or formulation components. These dangers are reduced, but not eliminated, by current manufacturing techniques. Furthermore, approximately 1 in 5 patients with severe hemophilia treated with recombinant or plasma-derived factor VIII develop inhibitory humoral immune responses. In some cases, new inhibitors have developed, apparently in response to unnatural modifications introduced during manufacture or purification.5 Gene therapy could circumvent most of these difficulties. In theory, a single injection of a vector encoding the factor VIII gene could provide constant plasma levels of factor in the long term. However, long-term expression after gene transfer of a systemically expressed protein in higher mammals has seldom been described. In some cases, a vector that appeared promising in a rodent model has not worked well in larger animals, for example, due to a massive immune response not seen in the rodent.6 An excellent review of early efforts at factor VIII gene therapy appeared in an earlier volume of this series.7 A summary of results from various in vivo experiments is shown in Table 1. This chapter will focus on results pertaining to studies using vectors based on murine retroviruses, including our own work.

High-Expression Porcine FVIII Driven by Erythroid-Specific Promoters for Lentiviral Vector-Mediated Gene Therapy

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3544-3544
Author(s):  
Nadia Sutherland ◽  
Kerry L Dooriss ◽  
David A McCarty ◽  
Christopher B Doering ◽  
H. Trent Spencer
Keyword(s):  
Gene Therapy ◽  
Factor Viii ◽  
Blood Cells ◽  
Copy Number ◽  
Hemophilia A ◽  
Lentiviral Vector ◽  
K562 Cells ◽  
Dna Copy Number ◽  
Normal Human ◽  
Globin Promoter

Abstract Hemophilia A is an X-linked gene disorder that results in a deficiency of circulating coagulation factor VIII (fVIII) and may be ameliorated by only modest amounts of circulating protein, which makes it a logical candidate for gene therapy. Due to the potential risk of insertional mutagenesis from oncoretroviral-mediated gene therapy, cell-specific expression of transgenes using self-inactivating viral vectors may provide a safer gene therapy approach for use in humans. Therefore, we constructed simian immunodeficiency virus (SIV)-based lentiviral vectors containing a 5′ long-terminal repeat (LTR) and 3′ LTR with self-inactivating U3 deletion, the bovine growth hormone polyA signal, a packaging signal (ψ), and a single internal ankyrin-1 or β-globin promoter, designated SIV-Ank and SIV-Bg, respectively. The minimal 314-bp ankyrin-1 promoter and 180-bp β-globin promoter flanked upstream by enhancing sequences, HS2, HS3, and HS4 (Hanawa et al., Hum Gene Ther, 2002) from the locus control region were cloned into the SIV vector backbone upstream from either enhanced green fluorescent protein (eGFP) or B-domain deleted porcine factor VIII (BDDpfVIII). The erythroid-specificity of each promoter was evaluated in vitro by measurement of either eGFP or fVIII expression following transduction of SIV-Ank and SIV-Bg constructs into both K562 myelogenous leukemic cells and 293T human embryonic kidney cells. GFP expression, as measured by flow cytometry, in transduced cells revealed that the ankyrin-1 and β-globin promoters are more active in K562 cells as compared to 293T cells. The β-globin promoter yielded higher mean fluorescent intensity values for GFP compared to the ankyrin-1 promoter at similar MOIs in K562 cells, suggesting stronger β-globin promoter activity in these cells. Transduction of cells with the SIV vector encoding BDDpfVIII driven by the β-globin promoter resulted in a 14-fold higher number of transcripts per DNA copy number in K562 cells compared to 293T cells, while cells transduced with the ankyrin-l promoter had only a 1.4-fold greater number of transcripts per DNA copy number. In addition, SIV-Bg-fVIII-modified K562 cells produced a 5.2-fold greater number of transcripts per DNA copy number than SIV-Ank- fVIII-modified cells. To evaluate the usefulness of these vectors for in vivo expression of BDDpfVIII, hemophilia A mice (exon 16 knockout) were conditioned with 11 Gy total body irradiation and transplanted with gene-modified Sca-1+ cells transduced with either SIV-Ank-fVIII, SIV-Ank-eGFP, SIV-Bg-fVIII, or SIV-Bg-eGFP. The expression of eGFP from donor red blood cells in recipient mice was approximately 8–12% using both the ankyrin-1 and β-globin promoter constructs. Mice that received cells transduced with SIVAnk- fVIII demonstrated therapeutic levels of plasma fVIII up to 0.5 units/mL (i.e. 50% normal human levels). However, fVIII expression decreased over time and real-time PCR analysis of peripheral blood cells confirmed the loss of detectable fVIII transgene by 6 weeks after transplantation, suggesting there was predominantly gene transfer into short-term repopulating hematopoietic cells. Mice transplanted with SIV-Bg-fVIII-modified hematopoietic stem cells demonstrated a similar rise and fall of fVIII expression within the first 4 weeks after transplantation, and showed an increase in fVIII expression by 6 weeks. At 8 weeks post transplantation, fVIII levels greater than 300% normal human levels were observed. Red blood cell count, hemoglobin, and red blood cell morphology were normal despite the high level of expression of fVIII. Overall these data demonstrate the potential for therapeutic expression of factor VIII using a self-inactivating lentiviral vector containing an erythroid-specific internal promoter.

scholarly journals Etranacogene dezaparvovec for hemophilia B gene therapy

2021 ◽  
Vol 2 ◽  
pp. 263300402110588
Author(s):  
Courtney D. Thornburg
Keyword(s):  
Gene Therapy ◽  
Clinical Trials ◽  
Continuous Production ◽  
Factor Ix ◽  
Hemophilia B ◽  
Clotting Factor ◽  
Plain Language ◽  
Long Term Follow Up

The treatment landscape for hemophilia has been rapidly changing with introduction of novel therapies. Gene therapy for hemophilia is a promising therapeutic option for sustained endogenous factor production to mitigate the need for prophylactic treatment to prevent spontaneous and traumatic bleeding. Etranacogene dezaparvovec is an investigational factor IX (FIX) gene transfer product that utilizes the adeno-associated virus (AAV) 5 vector with a liver-specific promoter and a hyperactive FIX transgene. Here, the development of etranacogene dezaparvovec and available efficacy and safety data from clinical trials are reviewed. Overall, etranacogene dezaparvovec provides sustained FIX expression for more than 2 years and allows for a bleed and infusion-free life in the majority of patients. Safety, efficacy, and quality-of-life data will inform shared decision-making for patients who are considering gene therapy. Long-term follow-up regarding duration of expression and safety are crucial. Plain Language Summary Factor IX Padua gene therapy to boost clotting factor and prevent bleeding for people living with hemophilia B People living with hemophilia have low or missing clotting factor, which can lead to bleeding that is unexpected or caused by a traumatic event (such as a sports injury or surgery). There are two main types of hemophilia: clotting factor (F)VIII deficiency (known as hemophilia A) and FIX deficiency (known as hemophilia B). People living with the severe or moderately severe forms of hemophilia (clotting factor levels below 3% of normal) need regular treatment, typically by infusions into the vein, to stop or prevent bleeding and damage to their joints. Gene therapy is currently being investigated as a new treatment option that introduces a working copy of the clotting factor gene to the liver. Following treatment, clotting factor is produced by the liver. Etranacogene dezaparvovec [Et-ra-na-co-gene dez-a-par-vo-vec] is a form of gene therapy for people living with hemophilia B. This form of gene therapy includes a modified form of FIX (FIX Padua) which produces high levels of FIX activity compared with normal FIX. It is being tested to see whether individuals will have low rates of bleeding and not need to treat themselves with clotting factor. In the clinical trials, participants with FIX levels below 2% (of normal) receive a single gene therapy infusion. The results of the trials have so far shown that patients given etranacogene dezaparvovec have continuous production of FIX, whereby they have reported much less bleeding and factor treatment. Questions relating to the safety of the gene therapy and how long it works will hopefully be answered through long-term follow-up of the patients once the trials are completed.

scholarly journals Expression of the blood-clotting factor-VIII cDNA is repressed by a transcriptional silencer located in its coding region

Blood ◽  
1995 ◽  
Vol 85 (9) ◽  
pp. 2447-2454 ◽  
Author(s):  
RC Hoeben ◽  
FJ Fallaux ◽  
SJ Cramer ◽  
DJ van den Wollenberg ◽  
H van Ormondt ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Factor Viii ◽  
Hemophilia A ◽  
Recombinant Dna ◽  
Transcription Unit ◽  
Current Treatment ◽  
Clotting Factor ◽  
Large Animal ◽  
Coding Region ◽  
Large Animal Models

Hemophilia A is caused by a deficiency of factor-VIII procoagulant (fVIII) activity. The current treatment by frequent infusions of plasma-derived fVIII concentrates is very effective but has the risk of transmittance of blood-borne viruses (human immunodeficiency virus [HIV], hepatitis viruses). Use of recombinant DNA-derived fVIII as well as gene therapy could make hemophilia treatment independent of blood-derived products. So far, the problematic production of the fVIII protein and the low titers of the fVIII retrovirus stocks have prevented preclinical trials of gene therapy for hemophilia A in large-animal models. We have initiated a study of the mechanisms that oppose efficient fVIII synthesis. We have established that fVIII cDNA contains sequences that dominantly inhibit its own expression from retroviral as well as from plasmid vectors. The inhibition is not caused by instability of the fVIII mRNA (t1/2, > or = 6 hours) but rather to repression at the level of transcription. A 305-bp fragment is identified that is involved in but not sufficient for repression. This fragment does not overlap the region recently identified by Lynch et al (Hum Gene Ther 4:259, 1993) as a dominant inhibitor of RNA accumulation. The repression is mediated by a cellular factor (or factors) and is independent of the orientation of the element in the transcription unit, giving the repressor element the hallmarks of a transcriptional silencer.

Toward Gene Therapy for Hemophilia A: Long-Term Persistence of Factor VIII-Secreting Fibroblasts after Transplantation into Immunodeficient Mice

1993 ◽  
Vol 4 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Rob C. Hoeben ◽  
Frits J. Fallaux ◽  
Nico H. Van Tilburg ◽  
Steve J. Cramer ◽  
Hans Van Ormondt ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Factor Viii ◽  
Hemophilia A ◽  
Immunodeficient Mice

How we treat a hemophilia A patient with a factor VIII inhibitor

Blood ◽  
2009 ◽  
Vol 113 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Christine L. Kempton ◽  
Gilbert C. White
Keyword(s):  
Factor Viii ◽  
Hemophilia A ◽  
Clotting Factor ◽  
Patient Specific ◽  
Factor Viii Inhibitor ◽  
Factor Viii Activity ◽  
Related Factors ◽  
Acute Bleeding ◽  
Viii Inhibitor

Abstract The most significant complication of treatment in patients with hemophilia A is the development of alloantibodies that inhibit factor VIII activity. In the presence of inhibitory antibodies, replacement of the missing clotting factor by infusion of factor VIII becomes less effective. Once replacement therapy is ineffective, acute management of bleeding requires agents that bypass factor VIII activity. Long-term management consists of eradicating the inhibitor through immune tolerance. Despite success in the treatment of acute bleeding and inhibitor eradication, there remains an inability to predict or prevent inhibitor formation. Ideally, prediction and ultimately prevention will come with an improved understanding of how patient-specific and treatment-related factors work together to influence anti–factor VIII antibody production.

scholarly journals Ultrasound Combined with Microbubbles Mediated Factor VIII Plasmid Gene Therapy in Hemophilia a Mice

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2039-2039
Author(s):  
Shuxian Song ◽  
James Harrang ◽  
Bryn Smith ◽  
Carol H. Miao
Keyword(s):  
Gene Expression ◽  
Gene Therapy ◽  
Gene Transfer ◽  
Factor Viii ◽  
Hemophilia A ◽  
Liver Perfusion ◽  
Transfer Efficiency ◽  
Clotting Factor ◽  
Gene Transfer Efficiency ◽  
Fviii Activity

Abstract Hemophilia A is a genetic bleeding disorder resulted from a deficiency of blood clotting factor VIII. In order to develop the efficient approach to gene therapy for hemophilia A, we previously explored reporter gene transfer mediated by ultrasound (US) combined with microbubbles (MBs). It was demonstrated that US/MB can significantly enhance gene transfer efficiency and serve as an efficient non-viral physical delivery strategy. In this study, we further delivered a therapeutic FVIII plasmid into the livers of hemophilia A (HA) mice. In consideration of FVIII synthesis from multiple tissues/cell lines, we first explored the distribution of gene expression using a pGL4.13 [luc2/SV40] luciferase plasmid driven by a ubiquitous promoter. One day following gene transfer, hepatocytes and endothelia cells were isolated from treated lobes by liver perfusion and centrifuge method. Evaluation of luciferase levels in two cell populations indicated that luciferase predominantly expressed in hepatocytes (5.35´104 RLU/107 cells vs. 1.46´103 RLU/107 cells in endothelia cells). Furthermore, gene transfer of pGFP (driven by a ubiquitous CMV promoter) mediated by US/MB also showed fluorescence distribution mostly in hepatocytes. These results indicate that hepatocyte is the predominant site of gene expression following US/MB mediated gene transfer into the liver. Based on these results, a hepatocyte-specific human FVIII plasmid (pBS-HCRHP-hFVIII/N6A) was used for US/MB mediated gene transfer in HA mice. In the short-term experiment, FVIII activity levels of treated HA mice ranged from 4-40% of normal FVIII activity. To follow FVIII expression for longer term, HA mice were pretreated with IL-2/IL-2 mAb (JES6-1) complexes on day −5, −4, and −3 to prevent immune response. In addition, the mice were infused with normal mouse plasma and human FVIII protein prior to gene transfer to maintain hemostasis. Subsequently, FVIII plasmids and 5 Vol% NUVOX MBs were injected into the mouse liver under simultaneous US exposure (1.1MHz transducer H158A driven by a pulse generator and high-power radio frequency amplifier capable of generating up to 1000W). Blood and liver samples were collected at serial time points after treatment to determine FVIII activity in plasma and liver damage. Following gene transfer, 10-30% of FVIII activity was achieved on day 4 and persisted in the average level of 20% by day 28. In a separate long-term follow-up experiment (n=3), 2 of 3 mice still maintained 10-30% activity after 120 days. Both transaminase levels (alanine aminotransferase and aspartate aminotransferase) and histological examination showed that the procedure of plasmid/MBs portal-vein injection and pulse-train acoustic exposure produced transiently localized liver damages however the damages were repaired and the liver recovered rapidly. Phenotypic correction of HA mice was further examined by tail clip assay. Blood loss of US/MB treated mice was significantly reduced compared with naive HA mice. Furthermore, a novel plasmid encoding a B domain-deleted FVIII variant containing mutations of 10 amino acids in the A1 domain (BDDFVIII-X10, a kind gift from Weidong Xiao) was constructed. Preliminary results from ongoing study showed that the gene transfer efficiency could be further improved with better plasmid and more efficient immune modulation. Together all the results indicate that US/MB mediated gene transfer is highly promising for efficient and safe gene therapy of hemophilia A. Disclosures No relevant conflicts of interest to declare.

Factor VIII Half-Life and Clinical Characteristics of Severe Hemophilia A.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3091-3091
Author(s):  
Karin van Dijk ◽  
Johanna G. van der Bom ◽  
Eveline P. Mauser-Bunschoten ◽  
Goris Roosendaal ◽  
Peter J. Lenting ◽  
...  
Keyword(s):  
Factor Viii ◽  
Half Life ◽  
Clinical Characteristics ◽  
Hemophilia A ◽  
Linear Regression Analysis ◽  
Median Number ◽  
Clotting Factor ◽  
Severe Hemophilia ◽  
Single Centre

Abstract Introduction Patients with severe hemophilia A have considerably different factor VIII half-lives. Whether this is associated with clinical characteristics has not been reported. The aim of this study was to describe the effect of half-life on the clinical characteristics of patients with severe hemophilia. Patients and Methods Patients were selected from a single-centre cohort of 214 patients with severe hemophilia, born between 1944 and 1995. To improve efficiency we measured factor VIII half-life in the patients with the most severe and the mildest clinical phenotypes of severe hemophilia. Patients were selected according to age at first joint bleed, annual joint bleed frequency, clotting factor consumption and radiological Pettersson scores. A first blood sample was taken after a period of 72 hours in which the patient did not use factor VIII. After infusion with 50 IU factor VIII/kg, blood was collected at 15, 30 minutes and 1, 3, 5, 24, 30, 48 and 60 hours. From 1972 onwards, data on joint bleed frequency, clotting factor use and age at first joint bleed were collected from the patients’ files. Pettersson scores were performed at five-year intervals. For calculations of annual clotting factor use (IU/kg/yr) and number of joint bleeds per year, the last 5 years of follow-up were used. Linear regression analysis was used to assess the relation between clinical characteristics and factor VIII half-life. Results Factor VIII half-life was measured in 42 patients and ranged from 7.4–20.4 hours, with a median of 11.8 hours. One hour increase in factor VIII half life was associated with a decrease of 96 (SD 45) IU clotting factor use per kg per year (p&lt;0.05). Joint bleed frequency was similar in patients with a shorter and a longer factor VIII half-life. Median number of joint bleeds was 2.9 per year (interquartile range (IQR) 1.1–4.4) in patients with a factor VIII half-life shorter than 12 hours and 2.6 per year (IQR 1.0–4.8) in patients with a factor VIII half-life longer than 12 hours (p=0.84). Patients with a factor VIII half-life shorter than 12 hours had a median Pettersson score of 52 points (IQR 12–61) and patients with a factor VIII half-life longer than 12 hours had a median Pettersson score of 29 points (IQR 16–52; p=0.90). Conclusion: Patients with a shorter factor VIII half-life need more clotting factor to prevent joint bleeds and subsequent arthropathy than patients with a longer factor VIII half-life.

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