I've been fairly critical of RNA interference (RNAi) technology and the blockbuster deals that have been thrown around in its name. But the collaboration between RNAi expert Alnylam Pharmaceuticals (NASDAQ:ALNY) and medical-device maker Medtronic (NYSE:MDT) is something I think I can endorse -- perhaps because there weren't any billion-dollar figures getting tossed about in the announcement.

The deal builds on a 2005 collaboration between the two companies, which will first design a device -- an infusible pump -- for treating Huntington's disease. Medtronic will be responsible for the clinical development of the delivery device, with Alnylam's RNAi molecule targeted to the diseased gene in Huntington's patients. Medtronic will have sole marketing rights for the drug-device combination in Europe, and the companies will split the revenues in the U.S.

If the device is successful, the companies could collaborate on treating other neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease. The only limiting factor would be the design of the RNAi molecule; the drug-delivery device for the brain would remain mostly the same.

My main problem with RNAi isn't that it doesn't work. In fact, I've seen it work quite well on cells in a test tube. The problem is that to get it to work, the concentration of RNA molecules has to be extremely high. That's easy to do in a test tube, but it's not so easy to do in a human. Using an infusible pump to get the RNAi drug into the patient is a move in the right direction to alleviate the problem, but the companies -- mainly Alnylam, since it's the RNAi expert -- will still have to deal with degradation issues once the RNA molecule is inside the patient.

I expect that we'll see other partnerships between companies with RNAi programs, such as Merck (NYSE:MRK) and Isis Pharmaceuticals (NASDAQ:ISIS), and infusible-pump makers, such as Baxter (NYSE:BAX) and DURECT (NASDAQ:DRRX), the latter of which makes the ALZET Osmotic Pumps. The pumps wouldn't be limited to diseases of the brain and could be designed to deliver drugs for other diseases. In cases of cancer, for instance, the RNAi drug might make the cells in the tumor more susceptible to chemotherapeutics and thus increase the chances of killing the tumor.

The RNAi companies can also go after diseases that are easy to reach and don't require a pump. That's what Alnylam is doing with its RNAi drug, ALN-RSV01, to treat respiratory syncytial virus (RSV) infections. It's using an inhaled mist to target the lungs.

This is still a preclinical deal and not a reason by itself to jump on the Alnylam bandwagon. The addition of an infusible pump may solve one of the problems with RNAi technology, but having an RNAi product make it to market is still far from a sure thing.

RNAi can't silence this Foolishness:

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Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. The Fool has a disclosure policy.