It is being hailed as one of the biggest advances in biology in decades, one that could eventually lead to drugs for a wide range of diseases, from cancer to diabetes to AIDS. And one startup, Cambridge, MA-based Alnylam Pharmaceuticals, is in a particularly strong position to transform it into new pharmaceuticals.

In 1998, scientists discovered that RNA interference (RNAi)-a natural process in which small, double-stranded RNA molecules shut down the activity of particular genes-takes place in animals. For biomedical researchers, the implications were obvious; if you could selectively block genes involved in a disease, you could, in theory at least, stop it. Founded in 2002 by some of the pioneers of RNA interference research, Alnylam aims to synthesize small RNA molecules that could become the basis for a broad class of new drugs. So far, Alnylam has focused on cancer and metabolic diseases like diabetes. Its ambitious goal is to have a drug candidate in human testing by the end of 2005.