Alnylam Touts Early Evidence of RNAi Drug Efficacy

2/29/08Follow @wroush

In 2006, the Nobel Prize in medicine went to two American biologists, Stanford’s Andrew Fire and UMass Medical School’s Craig Mello, who had discovered a way to shut off individual genes by blocking key RNA molecules in the cell. But while the technique, called RNA interference or RNAi, immediately became a powerful research tool, it was unclear how quickly it could be translated into drugs to treat the myriad health conditions that crop up when gene activity is out of whack. At a meeting in Singapore today, however, researchers from Alnylam Pharmaceuticals (NASDAQ: ALNY) of Cambridge, MA, are reporting what they call the first evidence of the effectiveness of an RNAi-based treatment in humans.

In a Phase II trial, researchers deliberately exposed 88 healthy adults to respiratory syncytial virus, or RSV, which mainly affects the breathing passages and can be life-threatening for infants and elderly people. Some of the volunteers, who were all men living in London, England, received a placebo treatment, while others received a five-day, nasally administered course of Alnylam’s ALN-RSV01, which is believed to shut down a gene that’s hijacked in infected lung cells to let RSV replicate. Compared to the placebo recipients, volunteers receiving the RNAi drug had a 38 percent lower rate of developing an RSV infection, Alnylam said in a press release. The effect was statistically significant, and the drug had no untoward side effects in the study, the results of which are being presented at the International Symposium on Respiratory Viral Infections in Singapore but have not yet been published in a peer-reviewed journal.

According to the Wall Street Journal, a Miami company called OPKO Health is contesting Alnylam’s claim that its study is the first to demonstrate a health benefit of an RNAi treatment in humans. OPKO says it conducted a trial in 2006 showing that its own RNAi-based drug was effective against macular degeneration, a leading cause of blindness, but the effect fell just short of statistical significance.

Alnylam–which is named after Alnilam, the center star in Orion’s belt—was founded in 2002 by MIT biologists Philip Sharp (an Xconomist) and Dave Bartel and three other researchers. The company’s initial venture backing came from Polaris Venture Partners and Cardinal Partners, and ARCH Venture Partners and Atlas Venture joined later financing rounds. The company went public in 2004. As of 1:30 EST, Alnylam’s stock was trading at around $29.50, down approximately 1.5 percent from Thursday’s close.

Wade Roush is a contributing editor at Xconomy. Follow @wroush

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