What is Lexgenleucel-T (VRX-496)?
- Lexgenleucel-T/VRX-496 is an immune-based gene therapy being developed by the VIRxSYS.
- Lexgenleucel-T is an antisense molecule inserted inside CD4 cells using a vector called VRX-496. The antisense targets HIV’s envelope gene. When the antisense molecule binds to the gene, HIV can’t produce functional new copies.
- The goal of Lexgenleucel-T/VRX-496 therapy is to allow people to go without ARV drugs for long periods of time, perhaps indefinitely.
What is already known about Lexgenleucel-T (VRX-496)?
- The Lexgenleucel-T is packaged inside an HIV-like virus (a vector) called VRX-496 capable of delivering the antisense molecule to CD4 cells. Once the antisense molecule is integrated into the CD4 cell’s DNA, it gets produced whenever HIV infects the cell. The antisense, which is a genetic mirror image of HIV’s envelope gene, binds to that gene, rendering the virus less able to reproduce or infect other cells.
- Therapy involves taking an HIV-positive person’s CD4 cells out of the body, treating the cells with VRX-496 to insert Lexgenleucel-T, expanding the number of genetically modified CD4s to produce a large number of new cells, and then reinfusing them back into the body.
- Three studies of Lexgenleucel-T/VRX-496 have been conducted thus far and a fourth is being planned.
- In the first Phase I study, people with multidrug HIV resistance were treated with a single infusion of Lexgenleucel-T-modifed CD4 cells. There were no serious side effects, and researchers documented signs that the cells were long-lived and that the treatment had some antiviral effect and provoked CD4 cell increases.
- In a follow-up Phase II compared multiple infusions of Lexgenleucel-T-modifed CD4 cells with a single infusion in 43 treatment experienced people. The latter was most likely to boost CD4 counts and was selected for further development.
- A third, Phase I/II study was conducted in 18 people who had well suppressed HIV on antiretroviral (ARV) therapy. Participants were treated with up to six infusions over sixteen weeks, and then had their ARV therapy withdrawn one month after the last infusion was given. In most cases, people’s virus levels remained lower than the levels documented before they started ARV therapy and there was further evidence of CD4 cell increases.
- A further fourth trial in treatment-experienced people is planned.
- Researchers involved in the studies have presented evidence that the Lexgeneucel-T-treated CD4 cells are quite long lived and that HIV produced by those cells is less infectious.
- Like other drugs, Lexgenleucel-T/VRX-496 might interact with other medications, including those used to treat HIV. It is important that your personal physician and/or the research nurse or study investigator be aware of all drugs you are taking, including those you buy without a prescription.
What is known about side effects?
- Information regarding the safety and possible side effects of Lexgenleucel-T/VRX-496 in HIV-positive people has not yet ben reported. Studies to determine the potential side effects of Dermavir have not yet been conducted.
Who should not take Lexgenleucel-T (VRX-496)?
- It is not known whether Lexgenleucel-T/VRX-496 will harm an unborn baby. It is very important to treat HIV during pregnancy to reduce the risk of infecting your baby. Talk to your provider about your treatment options.
- It is not known how Lexgenleucel-T/VRX-496 will affect babies who are breast-feeding when the mother while the mother is being treated. To prevent transmission of the virus to uninfected babies, it is recommended that HIV-positive mothers not breast feed.
Where can I learn more about clinical trials of Lexgenleucel-T (VRX-496)?
- If you would like to find out if you are eligible for any clinical trials that include Lexgenleucel-T/VRX-496, visit ClinicalTrials.gov, a site run by the U.S. National Institutes of Health. The site has information about all HIV-related clinical studies in the United States. For more info, you can call their toll-free number at 1-800-HIV-0440 (1-800-448-0440) or email firstname.lastname@example.org.