A new approach to combating HIV shows promise, reports the company that devised the new method. The private biotech company VIRxSYS announced that its method of gene therapy, which relies on lentiviral viral delivery, has shown promising results in a Phase II trial. Lentiviruses typically have long incubation periods, and have the capacity to splice large amounts of genetic information into a host’s own genetic code.
HIV itself is a lentivirus. The new method approaches treatment of the AIDS virus by using modified HIV virus, called VRX496, to attack and destroy the protective shell, or envelope, of the virus within living cells. Typically, viruses reproduce by taking over the replication machinery of a living cell, turning the cell into a factory that pumps out more copies of the virus.
By attacking the protective envelope of the HIV virus, the new therapy suppresses the viability of the HIV virus, meaning that the virus can no longer replicate itself as successfully.
Unlike ordinary pharmaceutical management of the virus, the gene therapy method does not involve flooding the body’s tissues with toxic substances that can lead to side effects for the organism as a whole. The company’s press release announced, "To date, there have been no reported adverse events in any patient receiving VRX496 in clinical trials."
Moreover, the new approach does not require daily ingestion of quantities of medication. In the company’s press release, Dr. Laurent Humeau, the vice president of research and development for VIRxSYS, cited "a measurable effect on the HIV replicative fitness up to 3 years following a single injection."
Said Dr. Humeau, "We believe this will prove to be an important step in the treatment of this disease."
Said Dr. Gary Blick, Medical Director at Circle Medical LLC, "This appears to be a significant demonstration of slowing and possibly halting the replication of the infectious HIV virus in humans."
Added Dr. Blick, "VRX496 appears to cause wt-HIV particles to lose their envelopes and the in vivo pressure delivered by a patient’s own modified cells leads to massive quasispecie reductions and production of impaired and less replicative virions."
Said Dr. Blick, "This treatment shows tremendous promise."
From the press release: "VRX496 is a different viral vector than those used in previous gene therapy trials. VRX496 is derived from HIV-1 itself and has it diseases-causing elements removed."
The release specified that the new treatment is meant to manage existing cases of HIV infection, and is not a vaccine: "Currently, VRX496 is being investigated as a therapeutic treatment (a treatment for those already infected with HIV)," read the release.
Other, similar methods have been investigated for the treatment of HIV, but VIRxSYS says that its approach seems superior to what has come before. "Unlike other viral vectors, lentiviral vectors appear to sustain expression of the delivered genes of interest for a longer period of time," the release said.
Continued the release, "Their safety profiles are currently being evaluated in clinical trials."
Dr. Riku Rautsola, the president and CEO of VIRxSYS, said, "These results are everything we’ve been hoping for."
Added Rautsola, "VRX496 is a remarkably promising treatment for HIV. We are very excited about what we are seeing so far in our trials and are confident that these results will continue into Phase 3."
Illustration: Scanning electron micrograph of HIV-1 budding from cultured lymphocyte. Wikipedia.
Yahoo! Finance (02/06/08)
Abstract (15th Conference on Retroviruses and Opportunistic Infections, Session 124, Tues. 1-4 pm, Hall A)