Significant strides utilizing gene therapy to create potentially effective HIV treatments continue to be made in our lab and others’. In addition to our work with Lexgenleucel-T (VRX496™) anti-HIV therapy, in which we modify autologous CD4 T cells to prevent HIV replication and is currently being tested in Phase II human clinical studies, we are seeing promising gene therapy reports out of other labs.
Nature Biotechnology has recently published a study conducted at UCLA in which stem cells, genetically modified with zinc finger nucleases to disrupt the viral co-receptor CCR5, were transplanted into humanized mice. After transplant, the mice were infected with HIV, as were control mice who received unmodified stem cells. The genetically modified cells multiplied into immune cells that successfully conferred HIV control. Mice that received the modified cells had higher human T cell counts and lower viral loads compared with animals that received unmodified cells. Although it will be several years before such research can be tested in human clinical trials, the success in humanized mice supports the potential for a successful gene therapy treatment for HIV. Clinical success of this type of approach will depend on several factors, including whether the HIV can mutate around this block as well as the specific tropism of HIV that a patient has. The study also provides further evidence that modifying just a fraction of the immune cells can potentially confer HIV resistance, much as we have observed in our Lexgenleucel-T studies to date.