Pfizer (NYSE:PFE) took in an orphan today. Or, more accurately, stole it from its parent.

Don't go calling the department of children and family services quite yet; this is an orphan drug, which means it treats a small patient population. But steal is still a pretty accurate term for the price Pfizer paid for Protalix BioTherapeutics' (NYSE:PLX) taliglucerase alfa, which the company has tentatively named Uplyso. The drug treats Gaucher's disease, a genetic condition in which people are unable to break down a certain type of fat, which causes enlarged spleens and livers.

Pfizer will pay $60 million up front and another $55 million in regulatory milestones. Assuming no problems on the manufacturing side, an approval from the Food and Drug Administration seems likely, considering the strong phase 3 trial data. For the total cost of $115 million, Pfizer owns 60% of the drug outside of Protalix's home country of Israel.

Genzyme (NASDAQ:GENZ) sold $1.24 billion worth of Cerezyme to Gaucher patients last year. Shire (NASDAQ:SHPGY) is also developing a Gaucher treatment called velaglucerase, so it'll likely be a three-way battle for patients in the coming years.

Normally, follow-on drugs into an orphan disease would have a hard time breaking into the market; that's the allure of companies like Genzyme and BioMarin Pharmaceutical (NASDAQ:BMRN). But Genzyme has been a train wreck the past year, including multiple manufacturing gaffes with Cerezyme. This has let Protalix make some of its drug available already under a special expanded access program approved by the FDA.

Genzyme's mistakes, combined with Pfizer's muscle, might eventually earn Uplyso a third of the market, or around $400 million per year, of which Pfizer would be entitled to about $240 million -- twice what it's paying for the drug.

Of course, Protalix will get its cash shortly and Pfizer will have to wait a few years to be paid back for the investment, but this looks like a low-risk deal that Pfizer's long-term investors should benefit from.

Pfizer is a recommendation of the Inside Value newsletter. If you're interested in picking through the wreckage for possible turnaround candidates, you should have the Inside Value team on your side. Check it out for free with a 30-day trial.

Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. BioMarin Pharmaceutical is a Rule Breakers pick. The Fool's disclosure policy has adopted the office copy machine as its own little pet.