Gene therapy for HIV scores early success
A method that specifically targets a single gene may have just had its very first success in the clinic!
Patients with the human immunodeficiency virus (HIV) were the first to receive the experimental gene therapy, which boosted their immune-cell counts.
The study was a phase 1 safety trial that tested enzymes known as ‘zinc finger nucleases,’ which are small proteins that can be designed to bind to and edit specific DNA sequences. The ones used here were developed by Sangamo BioSciences.
For the 6 men with HIV who participated, the standard regimen of highly active antiretroviral drugs (HAART) were keeping the virus at bay, but their immune-cell counts remained dangerously low.
- The researchers obtained samples of immune cells affected by HIV – known as CD4+T cells.
- Then they used Sangamo’s enzyme to disrupt the CCR5 gene, which encodes a protein that HIV uses to enter CD4+ cells.
- Then the engineered cells were then infused back into the patients.
The immune-cell counts rose for 5 of the 6 patients receiving the therapy. Researchers suspect that if they follow this procedure several times in a given patient, a high percentage of resistant cells could be established.
(Interesting fact: A small percentage of people have a natural mutation in the CCR5 gene and are actually resistant to most types of HIV infection.)
"Based on these very encouraging findings, we have recently extended our clinical studies to HIV-infected subjects who are not on HAART, or for whom HAART is no longer effective,” says Sangamo's Dale Ando.
The method could one day replace the more common technique of inserting modified genes into the genome; there, researchers have less control over the gene in question. But the technique still has a relatively low efficiency and might have off-target effects.
The results were presented at the Conference on Retroviruses and Opportunistic Infections in Boston on Monday.
From “Targeted gene editing enters clinic” [Nature News].
Image: HIV budding (green) via wiki
This post was originally published on Smartplanet.com