Upcoming Advances in HIV Gene Therapy
Rowena Johnston, Ph.D.In August, scientists will discuss their latest findings at the 5th Conference on Cell & Gene Therapy for HIV Cure in Seattle. amfAR’s research will feature prominently, including an update from ICISTEM, the amfAR-initiated and funded European consortium that reported a few months ago on the London patient. Several members of amfAR’s ARCHE-GT consortium will also report on their combination approach to cutting HIV DNA out of infected cells and boosting T cell and antibody responses against any remaining virus.
The promise of gene therapy is beginning to make its way into the clinic. In 2017, the FDA approved two CAR T cell therapies for cancers of the immune system, and another gene therapy to correct a gene mutation that causes retinal dystrophy. And in May 2019, Zolgensma was approved as a one-time treatment for children under two years of age with spinal muscular atrophy.
The number of FDA-approved gene therapies appears set to grow in the coming years, with nearly 4,000 clinical trials underway to address illnesses ranging from rare inherited conditions to those that rank among the most common killers, including cancer, heart disease, Alzheimer’s disease, and diabetes.
The Research Opportunities
In some respects, HIV is a conceptually simple target because it exists as a strand of DNA—much like a gene—inserted into the normal DNA of human immune cells. Indeed, many research groups are exploring a range of tools that could cut this strand of HIV DNA out of infected cells and thus remove the virus from the body.
However, HIV is a complex virus that provides numerous other avenues of attack. For example, some research groups are exploring whether cutting out the gene for CCR5, and thus removing the CCR5 protein—the main doorway through which HIV enters cells—might cure HIV along similar lines to the Berlin patient’s cure. The HIV remission observed in the London and Düsseldorf patients—members of amfAR’s ICISTEM cohort—lends additional optimism to this approach.
The possibilities don’t end there. Protective genes could be inserted; new or improved immune function could be engineered; individual or multiple HIV genes could be turned off; and any or all of these approaches could be combined with other gene or traditional therapies.
Anticipated Conference Highlights
The conference will begin with a session on stem cell transplantation and gene editing, featuring a plenary talk delivered by ICISTEM researchers. Subsequent sessions will feature updates on CAR T cells and other T cell therapies, as well as lessons from cell and gene therapy in other diseases.
Day two of the conference will focus on in vivo delivery of gene therapy. Researchers from amfAR’s ARCHE-GT consortium will present their progress on using different methods to deliver gene-editing tools, for example via intravenous injection.
Although gene therapy approaches have shown much promise in various diseases including HIV, they are currently very expensive. Thus far, approved gene therapies cost up to $2 million, partly due to the complexity of preparing the gene therapy product. In vivo delivery could make gene therapy substantially less expensive and more easily deliverable to people around the world living with HIV.
amfAR is currently supporting multiple gene therapy approaches to curing HIV and is providing support to the 2019 Conference on Cell & Gene Therapy for HIV Cure.
Researchers looking for more information about the conference, including registration and late-breaker abstract submission, should visit https://www.cgt4hivcure2019.org/
Dr. Johnston is an amfAR vice president and director of research.