A rogue surgeon injects stem cells from a fetus into a sick man's brain. The cells morph and form body parts. When the man dies, the pathologist finds cartilage, skin and bone clumped in his brain.

The scene is not from a horror movie; it happened to Max Truex, a former Olympic runner who suffered from Parkinson's disease. The case sent a chill through the scientific community when it came to light 15 years ago and typifies some of the hurdles researchers have faced while trying to bring stem cell therapies to the market.

Now, it appears, their efforts are closer than ever to paying off.

Dozens of adult stem cell treatments are moving through clinical trials and showing early success, raising hopes that some could reach the market within five years.

"It will only take a few successes to really change the field," said Gil Van Bokkelen, chief executive of Athersys Inc and chairman of the Alliance for Regenerative Medicine. "As you see things getting closer and closer to that tipping point, you're going to see a frenzy of activity take place."

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Many of the trials focus on heart disease and inflammatory conditions, some of the biggest markets in medicine. The cells used are derived from adult tissue such as fat, or bone marrow, thereby circumventing the ethical concerns raised by the use of cells derived from embryos.
Data for the most part remains early, but as more results emerge, pharmaceutical companies are beginning to take note.

"A lot of big companies are looking to place bets on some Phase II products once that data has been confirmed," said Paul Schmitt, managing partner at venture capital firm Novitas Capital. 

"Even now they're attending all the medical meetings and talking to all the stem cell companies."

Venture funds like Novitas are taking different approaches to playing the emerging field. Novitas invested $4 million in Amorcyte Inc, a company recently acquired by NeoStem Inc that is developing a treatment for heart disease. It is sticking to that investment for now.

Life is like a box of chocolates.

- Forrest Gump

By contrast, Aspire Capital Partners LLC is investing more broadly in the hope that one success will offset the inevitable failures.

"My philosophy in the stem cell space is that it's very difficult at this point to pick the winners and losers," said Steven Martin, managing member at Aspire. "We believe that over time there will be some very significant clinical progress, and valuations will improve, but we're still a long way from an approved therapy."

In the meantime, he said, "we are willing to be patient because we think the upside is tremendous."