The medical potential of reprogrammed stem cells that do not require the destruction of embryos was exaggerated, according to the head of one of the world’s leading regenerative medicine companies, The Times of London reported Wednesday.

Thomas Okarma, the chief executive of Geron Corporation, said that while so-called induced pluripotent stem (IPS) cells would be extremely useful in research, they were unlikely to be suitable for transplanting to patients to treat disease.

IPS cells are made by genetically manipulating adult skin cells to give them the versatile properties of embryonic stem (ES) cells. They caused excitement because they might provide a limitless source of replacement tissue for treating conditions such as spinal paralysis, Parkinson’s disease and diabetes without the need to destroy embryos.

As cells could be grown from a patient’s own tissue they would be genetically matched, therefore minimizing the risk of rejection by the immune system.

But Okarma, whose company expected to begin the first patient trial of an ES cell therapy this summer, said IPS cells had significant disadvantages to embryonic tissue if used in medical treatments.

He said the need to produce fresh IPS cells for every patient would make it uneconomical.

Regulatory issues could create further problems. Under current European and American rules, every new set of cells for each patient would have to be approved independently. ES cells remained a far more attractive option because they could be standardized and mass-produced for thousands of patients.

"IPS cells have been talked up as therapy by people with no experience of developing therapies," Okarma said.

"There is simply no business model for getting treatments based on your own cells into your body. The degree of difficulty in getting regulatory approval is just too great when you’re making new therapeutic cells from scratch every time.

IPS cells were still likely to have great value in medical research, he said. They could provide powerful cell models for investigating genetic disease and developing drugs.

"The science is sound and very exciting," he said.

"The ultimate potential will be in identifying the mechanisms and pathways of genetic disease, and screening new treatments. That would be a huge success."

SOURCE LINK: Times Online