Amid a tough week for biotech, a few companies had it worse than others. Alnylam, Isis Pharmaceuticals, Regulus Therapeutics, Dicerna Pharmaceuticals and Tekmira Pharmaceuticals have all sunk by more than 12 percent in the last week, compared with a 6 percent drop for the Nasdaq biotech index.
What do they all have in common? They're working in RNA therapeutics, a technology that aims to stop production of disease-causing proteins.
On Monday, the area was dealt a blow when drug giant Novartis said it was getting out of the technology, citing "ongoing challenges with formulation and delivery" and a narrow set of potential medical applications, according to FierceBiotech, which broke the news.
Novartis' move followed an exit by Merck in January, when it sold the unit it purchased for $1.1 billion in 2006 to Alnylam for just $175 million plus potential payments tied to product success. But to call this week's news a setback for RNA companies touches a nerve for some.
"As we know from the story of recombinant DNA and monoclonal antibodies, big pharma has been a miserable barometer of new platforms and innovation," Barry Greene, Alnylam's president, said Wednesday in a telephone interview. "They abandoned monoclonal antibodies in the '90s, claiming lack of commercial relevance, and didn't get back in until it was a major commercial reality. The same story's playing out with RNAi."
Monoclonal antibodies are drugs designed to target specific proteins that cause disease, and have become a key part of treatment for maladies like cancer. Herceptin, a medicine for breast cancer that draws $6.9 billion in annual revenue for Swiss drugmaker Roche, is one example.
RNA therapeutics go a step further back in the biological process. Instead of targeting problematic proteins, drugs using Alnylam's technology, called RNA interference, or RNAi, aim to prevent those proteins from ever being created. Alnylam describes the approach as turning off a faucet to stop a flood, rather than mopping up the water after the fact. The discovery of RNAi won the Nobel Prize in physiology or medicine in 2006.
The technology has yet to prove it can rival monoclonal antibodies. The first major RNA-focused drug, Isis' Kynamro, was approved in the U.S. only last year. The technology has been dealt some setbacks as researchers struggled to work out how to deliver the therapies to the right sites in the body.
Alnylam, though, says it's got that figured out.
"We've spent eight, nine, 10 years solving delivery and we know we can deliver now," Greene said of his company, which aims at targets in the liver. "What we've done is pick important targets in hepatocytes that are genetically validated for big unmet-need diseases. That's what we've solved, so that's what we're doing."
The company, and the field, got a big boost in January when French drugmaker Sanofi paid $700 million for a stake in Alnylam. The announcement came right at the start of JPMorgan Chase's annual health-care conference in San Francisco, setting the meeting abuzz with talk of RNA therapeutics' potential.
Greene said the momentum at Cambridge, Mass.-based Alnylam continues, with data coming on its experimental medicines at medical meetings including ATVB, or Arteriosclerosis, Thrombosis and Vascular Biology Scientific Sessions, in Toronto in early May.
Its most-advanced drug, patisiran, is in the third and final stage of testing generally required for regulatory approval. It aims to treat an inherited disease caused by mutations in the TTR gene that can lead to nerve and heart damage and is often fatal.
"We're sitting down with people and saying, in the case of TTR, this is the protein that causes the disease; look, we make the protein go away," Greene said. "There is amazing enthusiasm for that approach."
Midday Wednesday, Alnylam shares had lost more than 18 percent in the last week, while Isis had fallen 12 percent. Regulus dropped 15 percent, Tekmira 36 percent and Dicerna 27 percent.
—By CNBC's Meg Tirrell.