The 1 hemophilia gene therapy program that currently differs significantly from the growing number of AAV studies is the recently opened phase 1 trial of platelet-derived FVIII gene therapy in hemophilia A patients with FVIII inhibitors.31 This program, centered at the Medical College of Wisconsin in Milwaukee, utilizes autologous CD34+ peripheral blood stem cells transduced ex vivo with a FVIII lentiviral vector and the application of a reduced intensity conditioning regimen to facilitate stem cell engraftment. The gene discussed is F8; the disease is hemophilia A.