Sangamo says study shows ZFN therapy can make cells resistant to HIV

By E. Janene Geiss

Philadelphia, Dec. 19 - Sangamo BioSciences, Inc. announced Monday that data from its program to develop a ZFP therapeutic for HIV/AIDS demonstrated that cells can be made resistant to HIV infection by treatment with its proprietary zinc finger DNA-binding protein nucleases (ZFN) designed to specifically disrupt the CCR5 gene.

In its anti-HIV preclinical research program, Sangamo said it has designed ZFNs that can be used to disrupt the CCR5 gene, a receptor required for HIV entry into immune cells, according to a company news release.

The researchers found that ZFN-modified cells were resistant to HIV infection, whereas control cells were infected when challenged with the virus. When CCR5 expression was experimentally restored in the ZFN-modified cells, HIV was once again able to infect these cells, officials said.

Sangamo has shown disruption of the CCR5 gene in a number of different cell types including T-cells, the target cell for this therapeutic approach.

"CCR5 is an important target in the fight against HIV/AIDS," Edward Lanphier, president and chief executive officer, said in the release.

Company officials said that individuals with a natural mutation of their CCR5 gene have been shown to be resistant to HIV infection.

Several major pharmaceutical companies have begun programs to develop small molecule drugs to block HIV binding to CCR5, officials said, but in recent months two trials have been halted, one due to reports of liver toxicity of the candidate drug.

Using ZFNs to permanently modify the CCR5 gene specifically in T-cells and thus directly block the expression of the protein on the surface of these cells may have several advantages over the systemic effects of other drugs in development, officials said.

The study results were presented at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy in Washington, D.C.

"After the recent negative news regarding trials with pharmacologic blockade of CCR5, it is very important that we focus on positive results involving this well-validated disease target. I am encouraged by Sangamo's findings and look forward to collaborating with the company further to bring this promising approach into the clinic," said Carl June, director of translational research at the Abramson Family Cancer Research Institute at the University of Pennsylvania School of Medicine, in the release. June is known as a leader in research of T-cell therapies for cancer and HIV infection, officials said.

Sangamo is a Richmond, Calif., biopharmaceutical company focused on research and development of novel DNA-binding proteins for therapeutic gene regulation and modification.

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