Another Next-Generation RNAi Startup Emerges, Makes Big Claims About Its Ability to Silence Bad Genes

12/18/08

I was initially skeptical when I first heard about biotech startup AiRNA Pharmaceuticals and its new approach to RNA-interference (RNAi already gets lots of attention for its ability to silence genes for cancer and many other diseases). The Norwood, MA, firm claimed in a press release that its next-generation RNA-interference (RNAi) technology is “superior” to other RNA-blocking methods. That would include the gold-standard approach, small interfering RNA, used by a heavyweight in the field, Alnylam Pharmaceuticals (NASDAQ:ALNY), among others.

So my internal hype alarm rang when I saw AiRNA’s claim to superiority. But then I talked to the inventor, Chiang Li, chief executive of Norwood-based biotech firm Boston Biomedical. He convinced me that AiRNA, which is a spin-off of Boston Biomedical, could be on to something big.

AiRNA is developing so-called asymmetrical interfering RNA (aiRNA)—made public in the December issue of Nature Biotechnology—which uses a molecule of 15 base pairs in length. This structure is different than small interfering RNA (siRNA) molecules, which are 19-21 base pairs long. Cambridge, MA-based Alnylam, for one, has built a company with a market cap approaching $1 billion around siRNA technology.

“[Asymmetrical interfering RNA] is essentially the next generation of the technology that can silence genes but with improved gene-silencing properties,” Li says. “It’s the same as siRNA, in that it can theoretically target almost any disease gene.”

How does AiRNA’s approach stack up against Alnylam’s well-known technology? The inventors of aiRNA say that their asymmetrical molecules, which were tested in mammalian cells in the study published by Nature Biotech, have fewer unintended effects on non-targeted genes, better silencing efficiency and duration, and will cost less money to make than the longer siRNA molecules.

AiRNA isn’t the first startup to come along with an alternative to siRNA. Dicerna Pharmaceuticals, based in Watertown, MA, believes that its longer molecules of 25-35 base pairs work earlier in the gene-silencing process and for longer durations than other RNAi methods. (Luke wrote about Dicerna’s technology and latest financing earlier this year.)

Still, it’s early days for AiRNA and its aiRNA technology. Li says that the startup operates with a small science team, which he supervises, in a separate lab at the same building as Boston Biomedical’s office. And the company has just begun to raise funds.

Li is no newcomer to the gene-silencing field—or the biotech industry, for that matter. He’s a co-founder and director of Cequent Pharmaceuticals, a Cambridge-based biotech startup developing so-called transkingdom RNAi for gastrointestinal disorders. Cequent’s RNAi technology—discovered by Li and others in his lab at Beth Israel Deaconess Medical Center, Harvard Medical School in Boston—uses modified bacteria to deliver and produce RNAi molecules in cells.

Li is also the scientific founder of ArQule, (NASDAQ:ARQL), a Woburn, MA-based developer of cancer treatments, where he served as chief scientific officer. He led the spin-off of Boston Biomedical from ArQule in January 2007. Boston Biomedical is focused on small molecule drugs to target cancer stem cells.

“I believe that [aiRNA] is actually a big breakthrough in the field,” says Johannes Fruehauf, vice president of research at Cequent. Fruehauf was among the researchers who discovered transkingdom RNAi in Li’s lab a Beth Israel. Fruehauf says that AiRNA’s and Cequent’s technologies are distinct from each other, and there are no plans to combine them.

AiRNA’s initial focus will be to develop RNAi drugs for cancer, inflammation, and infectious diseases, Li says.

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