Advancements in gene therapy for hemophilia: Overcoming challenges with lentiviral vectors

Abstract

Hemophilia is X-linked recessive inherited trait that is resulted from faulty or deficiency of clotting factors VIII and IX (genes) i.e., Hemophilia A (HA) and Hemophilia B (HB) respectively. Absence of these factors causes stoppage of coagulation cascade that results in bleeding problems to internal organs. HA is more prevalent than HB with US bearing the most cases in the world and it has been reported that white is affected more than black people. Conventional treatments didn’t give complete relief and need to be repeated throughout life but gene therapy could be the possible and long-lasting treatment that gives hope to treat genetic disorders. Two types of viral vector systems are used to deliver the cargo i.e AAV and LV vectors. The main loopholes of AAV vector are firstly, the capacity of cargo i.e 4.7 kb however the FVIII transgene size is 4.4 kb that restrict choice for promoter and secondly, the gradual loss in transgene expression. These loopholes have been overcome with the use of LV up to greater extant. HIV derived self-inactivating lentivirus vector is used to for the transformation of CD34+ cells. The autologous cell product mechanism resulted in a successful restoration of F8 production diminishing hemophilia A.