Use of Cloning to Tailor Treatment Has Big Hurdles, Including Cost

A Massachusetts biotechnology company, Advanced Cell Technology, provoked a storm of outrage last month by reporting that it was trying to create human embryos by cloning. But the company faces another difficult challenge: its goal, the use of such therapeutic cloning to produce useful treatments, may simply be impractical.

That is because the approach, if it works, will involve cloning patients individually in order to develop treatments tailored to them.

"It's too laborious and costly to employ as a routine therapeutic procedure," said Dr. Alan Colman, research director at PPL Therapeutics, the Scottish company that helped cloned Dolly the sheep.

Other leading stem cell companies apparently agree.

For one thing, unless success rates improve drastically, the therapeutic cloning will require a large number of eggs — and women willing to donate them — to make clones for the thousands or even millions of potential patients.

"They're never going to have enough women's eggs available to do it," said Dr. Alan Trounson, director of the Monash Institute of Reproduction and Development in Australia and an adviser to ES Cell International, a...