Oral Pill May Make Tough-to-Deliver RNAi Drugs Go Down Easy, RXi Says

11/13/08Follow @xconomy

Everywhere he goes in biotechnology circles, RXi Pharmaceuticals’ CEO Tod Woolf hears the same criticism of RNA interference drugs. What can be done to overcome the challenge with drug delivery?

The answer is, nobody knows until it’s been proven with an effective drug. But Worcester, MA-based RXi (NASDAQ: RXII) says it has obtained the exclusive right to technology from the University of Massacusetts Medical School which could hold the key for the first way to deliver these drugs through the mouth.

The problem of how to deliver RNA interference drugs has been around since the technique was co-discovered a decade ago by one of RXi’s founders, UMass researcher Craig Mello. These drugs are thought to have the advantage of being able to specifically hit targets on cells that other drugs can’t, and to get at the genetic root cause of disease. The problem is that small interfering RNA drugs can get chewed up by enzymes in the body, or flushed through the kidneys into the urine long before they ever get to the diseased cells, Woolf says.

Other companies, like Cambridge, MA-based Alnylam Pharmaceuticals (NASDAQ: ALNY) are packaging the RNAi molecules along with other materials, like polymers, fat droplets called liposomes, or nanoparticles that will make them stable long enough in the blood to do their business, Woolf says. Researchers have also tried localized delivery to tissues like the lungs, a joint, or the eyes.

“A lot of people talk about delivery, delivery, delivery,” Woolf says. “We’ll all be working on this for the next 20 years.”

There doesn’t appear to be one silver-bullet answer for drug delivery. Woolf says RXi now believes the best delivery method will vary from tissue to tissue, disease to disease.

In RXi’s case, it is testing out an oral pill in animals that could work for inflammatory diseases like rheumatoid arthritis, asthma, Crohn’s disease, psoriasis, atherosclerosis, and Type 2 diabetes. This approach is unusual, because most companies have long believed oral delivery of RNA interference drugs was impossible, Woolf says. … Next Page »

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