Stem cells ready for extraction from a five-day-old embyoThe U.S. patent office has invalidated some key stem-cell patents, a significant move that could shake up a potentially huge market for embryonic stem-cell therapies that may one day restore all kinds of body parts for the sick and injured.

Yesterday, the U.S. Patent and Trademark Office announced a preliminary decision to invalidate three fundamental stem-cell patents held by the Wisconsin Alumni Research Foundation (WARF), the technology-transfer arm of the University of Wisconsin. Last year, two public-interest groups asked the patent office to re-examine those patents, arguing that they should never have been issued because their descriptions of human embryonic stem cells and the process for deriving them weren’t new. The patent office effectively agreed, finding that previous scientific publications and patents undermined WARF’s claimed innovations (decisions here, here and here (PDF), courtesy of the Foundation for Taxpayer and Consumer Rights).

WARF and its primary stem-cell business partner, Geron, have long used these patents to claim a monopoly of sorts over just about any therapy or diagnostic test that might emerge from stem-cell work. (WARF and Geron even tussled briefly in an acrimonious legal spat five years ago that ultimately led to a dramatic narrowing of Geron’s exclusive commercial rights over the cells.) Many academic researchers argue that the patents have had a chilling effect on stem-cell research, and some companies have complained about the cost of licensing them as well. Invitrogen, for instance, said it moved its stem-cell work overseas where the WARF patents don’t apply.

So the invalidation of the WARF patents could have a significant, albeit unpredictable, effect on the nascent science of stem cells. Some academic research might move ahead more quickly, although the relative paucity of major support from government or Big Pharma has so far presented a much bigger impediment to the work. On the commercial side, Geron could lose its remaining exclusive rights to derived neural, pancreatic and heart cells, leaving would-be competitors such as Novocell free to forge ahead — although David Greenwood, Geron’s chief financial officer, says the company’s own patent estate should shield it in that respect.

In fact, though, it may be years before anyone knows how this will all turn out. WARF said it will defend its patent claims “vigorously,” and has Geron’s support. The foundation will first argue its case directly with the patent examiner, and if that fails, will likely take its argument to a patent-appeal board. Even that board’s decision won’t be final, though, since WARF can always turn to the courts. At least by the time the process plays out, stem-cell science may have progressed far enough for us to know if all this arguing was really worth it in the first place.

The NYT has more info here.