Disease-causing proteins can be inhibited by small-molecule drugs or by antibody drugs that bind to the protein, but there's a third class of drugs being developed that prevents the protein from being produced in the first place. They target mRNAs, the intermediary between genes (DNA) and the proteins they code for.
The nucleic-acid drugs bind to the mRNA and signal for destruction. Reduced levels of mRNA result in a reduction of the proteins they encode for.
RNA drugs generally come in two flavors. Isis Pharmaceuticals (NASDAQ: ISIS ) uses antisense to target the mRNA for destruction. The biotech has already proved that the technology works; its drug Kynamro, which is sold by partner Sanofi (NYSE: SNY ) , is already on the market. The biotech has a stocked pipeline of additional antisense drugs.
The other major class of RNA drugs is called RNAi, which use a different cellular mechanism to trigger degradation of the mRNA. The class isn't nearly as developed, because it was discovered later and companies had trouble targeting the drugs. Eventually they figured out how to target to the liver, so RNAi companies are going after liver diseases first.
Alnylam Pharmaceuticals' (NASDAQ: ALNY ) lead program treats TTR-mediated amyloidosis, a rare genetic disease that causes misfolding of a protein in the liver that can get intertwined and deposited elsewhere, causing nerve and heart problems. Arrowhead Research (NASDAQ: ARWR ) is developing a hepatitis B drug called ARC-520.
Watch the following video for further insight on Isis Pharmaceuticals, Alnylam, and Arrowhead Research from the Fool's senior biotech specialist, Brian Orelli, and health-care analyst David Williamson.
Silicon Valley's next big thing
Every investor wants to get in on revolutionary ideas before they hit it big -- like buying PC maker Dell in the late 1980s, before the consumer computing boom, or purchasing stock in e-commerce pioneer Amazon.com in the late 1990s, when it was nothing more than an upstart online bookstore. The problem is, most investors don't understand the key to investing in hypergrowth markets. The real trick is to find a small-cap "pure play" and then watch as it grows in explosive fashion within its industry. Our expert team of equity analysts has identified one stock that's poised to produce rocket-ship returns with the next $14.4 trillion industry. Click here to get the full story in this eye-opening report.