Gene therapy and new drugs hold HIV promise

24 July 2007
Source: SciDev.Net

[SYDNEY] A human trial of gene therapy to treat HIV infection is underway and new anti-HIV drugs are yielding promising results, say scientists at an international HIV conference in Sydney, Australia.

Progress in anti-HIV strategies was reviewed in a plenary session at the conference today (24 July).

"Some of these agents will be useful to the developing world, that is witnessing emergence of drug resistance and urgently needs new treatment strategies," says Joseph Eron, professor of medicine at the US-based University of North Carolina School of Medicine.

"We need to expand the treatment regimen to make it less complicated and less toxic, and to tackle increasing drug resistance."

A team headed by John Rossi, professor of molecular biology at the US-based Beckman Research Institute, is testing gene therapy, where genes are injected into cells or tissue to treat disease.

They are investigating whether genetically modified stem cells — the body's master cells that can grow into any kind of cell — can be used to treat AIDS patients. 

Rossi's team built a unique anti-HIV agent by stitching together three short gene sequences. Two sequences target the HIV virus directly by interfering with its genetic material, while the third blocks the entry of the virus into a cell.

This agent is carried into the stem cells by a 'vehicle' — HIV itself made harmless by deactivating most of its genes.

The trial began in June 2007 on an AIDS patient in the United States (US) and will be tested initially on five other patients.

Rossi told SciDev.Net, "This triple construct is several times more powerful than azidothymidine, one of the widely used anti-HIV drugs," in laboratory tests.

Elsewhere, six new anti-HIV drugs are in advanced stages of testing, with two waiting for approval by the United States Food and Drug Administration.

Two are "integrase inhibitors" that block the HIV genetic material from attaching to the host cell's DNA. Two others block the entry of the virus into the host cell and the third group prevents the virus from producing copies of itself.

While saying it is up to the individual drug firms to fix their price, Eron added, "I urge the World Health Organization, the Joint United Nations Project on HIV/AIDS and the International AIDS Society to make these new drugs available not just in the US and Europe, but also in developing countries."

"The stronger the voice, the better off we are."