Adenovirus-Associated Virus Vector–Mediated Gene Transfer in Hemophilia B

Abstract

BACKGROUND Hemophilia B, an X-linked disorder, is ideally suited for gene therapy. We investigated the use of a new gene therapy in patients with the disorder. METHODS We infused a single dose of a serotype-8–pseudotyped, self-complementary adenovirus-associated virus (AAV) vector expressing a codon-optimized human factor IX (FIX) transgene (scAAV2/8-LP1-hFIXco) in a peripheral vein in six patients with severe hemophilia B (FIX activity, <1% of normal values). Study participants were enrolled sequentially in one of three cohorts (given a high, intermediate, or low dose of vector), with two participants in each group. Vector was administered without immunosuppressive therapy, and participants were followed for 6 to 16 months. RESULTS AAV-mediated expression of FIX at 2 to 11% of normal levels was observed in all participants. Four of the six discontinued FIX prophylaxis and remained free of spontaneous hemorrhage; in the other two, the interval between prophylactic injections was increased. Of the two participants who received the high dose of vector, one had a transient, asymptomatic elevation of serum aminotransferase levels, which was associated with the detection of AAV8-capsid–specific T cells in the peripheral blood; the other had a slight increase in liver-enzyme levels, the cause of which was less clear. Each of these two participants received a short course of glucocorticoid therapy, which rapidly normalized aminotransferase levels and maintained FIX levels in the range of 3 to 11% of normal values. CONCLUSIONS Peripheral-vein infusion of scAAV2/8-LP1-hFIXco resulted in FIX transgene expression at levels sufficient to improve the bleeding phenotype, with few side effects. Although immune-mediated clearance of AAV-transduced hepatocytes remains a concern, this process may be controlled with a short course of glucocorticoids without loss of transgene expression. (Funded by the Medical Research Council and others; ClinicalTrials.gov number, NCT00979238.)

Single Amino Acid Modification of Adeno-Associated Virus Capsid Changes Transduction and Humoral Immune Profiles

“…While no relationship was found between transduction, amino acid properties, and NAb titer or its cross-reactivity, these studies map a critical capsid motif involved in all steps of AAV infectivity. Our results suggest that AAV types can be utilized not only as templates to generate mutants with enhanced transduction efficiency but also as substrates for repeat administration.A deno-associated virus (AAV) vectors have been safely and successfully used in phase I clinical trials (39,40,54). In particular, therapeutic effects have been achieved in patients with Leber's congenital amaurosis and hemophilia B.…”

“…A deno-associated virus (AAV) vectors have been safely and successfully used in phase I clinical trials (39,40,54). In particular, therapeutic effects have been achieved in patients with Leber's congenital amaurosis and hemophilia B.…”

“…Among 30 patients with Leber's congenital amaurosis, 28 demonstrated remarkably improved eyesight after AAV type 2 (AAV2) delivery of the rpe65 gene to the retina. Regarding the recent hemophilia B trial, all six patients had therapeutic factor IX (FIX) expression within a beneficial 1% to 8% of normal levels as long as 18 months after intravenous delivery of an AAV vector encoding an optimized FIX cassette (54).…”

Adeno-associated virus gene therapy prevents hepatocellular adenoma in murine model of glycogen storage disease type Ia

“…These data are encouraging for advancing GSD-Ia translational research to bring the preclinical success to the bedside, which has already shown promise with gene therapy for other genetic diseases, such as hemophilia B. 19,20 LILI WANG, PH.D.…”

Construction and expression of a lentivirus expression vector carrying the VEGF165-EGFP fusion gene in breast cancer MCF-7 cells

“…To date, several viral vectors have been applied in laboratory experiments or clinical trials and have achieved good results (15)(16)(17). In the majority of cases, the efficiency of gene transfer represents the most relevant obstacle, since it limits the success of gene overexpression or gene silencing (18).…”