Who Will Grow A Liver First?

Geron may not be No. 1 in the race to grow human organs

On Nov. 6, scientists announced a major new advance: They had found a way to isolate human cells that can grow and become any part of the body. News stories predicted that so-called embryonic stem cells could one day grow replacemEnt livers or build new muscle for failing hearts. "We now have the possibility of repairing degenerating tissues," says Thomas B. Okarma, research chief at Geron Corp., the biotech firm that funded the research.

But other companies may already have found a quicker route to these marvels. Already, Baltimore-based Osiris Therapeutics Inc. has regenerated bone in animals using another type of stem cell. And in Lincoln, R.I., CytoTherapeutics Inc. plans to treat Parkinson's disease using a neural stem cell. "We're not talking about something 10 to 20 years away, like Geron," says CEO RichArd M. Rose, MD. Says James D. McCament, editor of Medical Technology Stock Letter, "CytoTherapeutics is much closer to the clinic and more significant from an investment standpoint."

The key to these swifter therapies lies in the types of stem cells being used. Geron snared the mother of all stem cells--a single cell that theoretically can become any part of the body. Osiris and the StemCells Inc. subsidiary of CytoTherapeutics are using stem cells already part way down the developmental path. These cells are no longer able to create any organ but are progenitors of specific body parts like livers or bone. And because these cells are partly Specialized, scientists are much closer to actual therapies. Indeed, medical researchers at University Hospitals in Cleveland are already using so-called mesenchymal stem cells to try to help women recover from side effects of breast cancer treatments.

Geron has to clear other hurdles, too: No one has any idea how to direct embryonic stem cells to make, say, a liver. And even if Geron scientists learn to direct embryonic stem cells down different developmental paths, it may not be able to capitalize on its breakthrough. Along the way, they could create the "daughter" stem cells that companies like Osiris and StemCells have already patented. AnalySts predict the company will find ways around the patents. But the embryonic stem cell hoopla could end up as breathtaking science that can't realize its enormous potential.