Benitec claims 'multiple warhead' RNAi breakthrough

Benitec (ASX:BLT) has developed technology allowing simultaneous disabling of multiple genes through RNA interference.

The company claims that the new technology, which it has dubbed a "multiple warhead", will be essential for the development of effective therapeutics against diseases with multiple gene defects and to combat the emergence of resistance.

"It's got not just us but our collaborators thinking that maybe even cures are possible, not just therapeutic treatments," said the company's R&D director, Dr Ken Reed.

Building on Benitec's ddRNAi platform technology, the multi-hit constructs are specifically designed to generate a range of small interfering RNAs targeting two to five genes, packaged into one cassette.

"It's a relatively straightforward concept to make RNAi constructs that will be chopped up by Dicer [RNase III] to hit your target gene. But to hit multiple genes is not so trivial," Reed said. "What we've done is to put in a series of discrete short segments interspersed with very short sequences to signal to Dicer to cut here."

From there, according to Reed, there are a number of ways to deliver the construct depending on whether permanent, long term or transient expression is required.

The new approach is likely to be used to target multiple HIV genes in a project the company is working on with a collaborator. Reed said targeting several genes at once would make it more difficult for the virus to sidestep the treatment by developing resistance.

A similar approach will be used to develop anti-cancer therapeutics, with as many as five genes being targeted at one time to disable the cell. But Reed said it would be unlikely that the company would be in Phase I clinical studies before 2005.

He said the new technology had been well received by collaborators. "It's a tremendous boost to their hoped-for gene therapy programs," he said.