Food for Thought: Posing Stem Cell Therapy at Risk
Many researchers agree that stem cells – whether they originate from embryos or from adults – bear great therapeutic potential. They are toti- or pluripotent cells, which by definition are able to regenerate all sorts of damaged tissue – provided their differentiation is confined to the desired environment, leads to the right type of tissue and can be controlled so as not to give rise to side effects, e.g. tumors.
How to fulfill these preconditions is under thorough investigation in many research institutions, but most experts agree that science is not there yet.
Nevertheless, some researchers have set out to try – and the danger is great that stem cell therapy therefore will follow the thorny gene therapy road that started in the early nineties with unfounded experiments, serious side effects, and deaths of patients.
The first stem cell therapy related death is already there: as reported by German magazine “Wirtschaftswoche” today, this month an eight years old boy died from cerebral hemorrhage after receiving an injection of autologous stem cells into his brain. He had been treated by researchers from German stem cell therapy company XCell-Center (Düsseldorf, Germany). In Germany, autologous stem cell therapies are regarded as individual medicinal products (“Individualarzneimittel”), which require a manufacturing authorization but no regulatory approval as a drug. Already in spring, a ten years old boy developed the same condition after stem cell treatment of his brain by XCell-Center. Luckily, he survived.
But the FDA-approved clinical trial involving embryonic stem cells that started in Atlanta, GA, last week is also met with scepticism by experts. In this trial, the first patient suffering from spinal cord injury was injected with about 2 million oligodendrocyte progenitor cells derived from human embryonic stem cells. While the researchers of Atlanta’s Shepherd Center and stem cell company Geron Corp., sponsor of the trial, hope that the cells will form a restorative coating around the damaged spinal cord, experts such as Volker Dietz, professor at Neuroscience Center Zurich and a specialist in treating paraplegic patients, react with “disgust and infuriation”. He told German Sunday paper “Frankfurter Allgemeine Sonntagszeitung” this weekend that the treatment approach was unfounded as the regeneration of nerve cells is far from being understood and previous experiments transplanting coating cells – the cells the US researchers are trying to generate – did not lead to any effects. Dietz said, among his fellow experts, he had “not heard a single positive voice yet”.
After two decades, gene therapy today is a niche application with sparse successes, which is the result of serious blows the field experienced after some of the first patients died from side effects such as leukemias. Consequently, parliaments, regulators, funding agencies and the public as well as investors regarded the field as dangerous and too risky to pursue. With trials not supported by many specialists and the first dead patient, it seems the same scenario is unfolding today. Therefore, today’s self-styled pioneers of stem cell therapy not only pose patients at risk, but the field as a whole.