Gene therapy strategies for hemophilia: benefits versus risks.
Hemophilia is an inherited bleeding disorder caused by a deficiency of functional clotting factors VIII or IX in the blood plasma. The drawbacks of the classical protein substitution therapy fueled interest in alternative treatments by gene therapy. Hemophilia has been recognized as an ideal target disease for gene therapy because a relatively modest increase in clotting factor levels can result in a significant therapeutic benefit. Consequently, introducing a functional FVIII or FIX gene copy into the appropriate target cells could ultimately provide a cure for hemophilic patients. Several cell types have been explored for hemophilia gene therapy, including hepatocytes, muscle, endothelial and hematopoietic cells. Both nonviral and viral vectors have been considered for the development of hemophilia gene therapy, including transposons, γ-retroviral, lentiviral, adenoviral and adeno-associated viral vectors. Several of these strategies have resulted in stable correction of the bleeding diathesis in hemophilia A and B murine as well as canine models, paving the way towards clinical trials. Although clotting factor expression has been detected in hemophilic patients treated by gene therapy, the challenge now lies in obtaining prolonged therapeutic FVIII or FIX levels in these patients. This review highlights the benefits and potential risks of the different gene therapy strategies for hemophilia that have been developed.
Petrus
Inge
I
Free University of Brussels, Vesalius Research Center, Flanders Institute of Biotechnology (VIB) & University of Leuven, Belgium.
Chuah
Marinee
M
VandenDriessche
Thierry
T
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D002986:Clinical Trials as Topic; D000229:Dependovirus / Q000235:genetics; D004285:Dogs; D005164:Factor IX / Q000235:genetics*; D005169:Factor VIII / Q000235:genetics*; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006467:Hemophilia A / Q000235:genetics / Q000628:therapy*; D006801:Humans; D051379:Mice; D012190:Retroviridae / Q000235:genetics
D005169:Factor VIII; D005164:Factor IX