Getting an infusion of ViroPharma's (Nasdaq: VPHM) Cinryze every three or four days to prevent hereditary angioedema attacks has to be a pain. It's better than having your face swell up, but still not very convenient.

As a result, ViroPharma is developing a version that can be delivered via subcutaneous shot. It'll still require a needle prick, but at least it won't need to be infused over time. It's a low-risk move -- the infused version is already on the market -- but there's no guarantee it'll work since it's harder to get high concentrations of drugs via subcutaneous injection.

So ViroPharma looks like its setting up a backup plan in case its own version doesn't work out. Yesterday, ViroPharma licensed Halozyme Therapeutics' (Nasdaq: HALO) recombinant human hyaluronidase enzyme to be combined with Cinryze. The technology, dubbed rHuPH20, creates channels through the tissue under the skin, which helps drugs it's injected with disperse.

Halozyme also has also licensed the technology to Roche and Baxter (NYSE: BAX), so it's not like ViroPharma is the guinea pig for the new technology. The two seem to have even done some laboratory experiments before setting up the licensing agreement to confirm that the drugs don't interfere with each other.

The partnership won't cost ViroPhama all that much. Halozyme gets $9 million now and another $3 million when the first phase 2 study starts. There's also up to $41 million in milestone payments related to success in hereditary angioedema, and up to another $30 million for three additional indications. Halozyme gets a 10% royalty, but ViroPharma should be able to make up for that by charging more because of the added convenience.

ViroPharma plans to start a phase 2 trial with the combination product in the second half of this year, so we should know sometime next year whether the combo product is a viable alternative.

Follow ViroPharma and Halozyme as they try to develop subcutaneous Cinryze. Click on their names to add them to My Watchlist, which will help you keep track of all our Foolish analysis on the companies.

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