The Glasgow-based stem cell company ReNeuron has been granted approval to begin clinical trials with its ReN001 product in the treatment of human corneal blindness. Approximately 20 patients will participate in the study, in which they will be treated with ReN001, which contains fetal stem cells harvested from aborted fetal tissue.
The trial will be conducted by Dr. Bal Dhillon and colleagues at the Princess Alexandra Eye Pavilion in Edinburgh, in collaboration with the Gartnavel General Hospital in Glasgow. According to Dr. Dhillon, “This study is the first of its kind anywhere in the world and it is exciting to be involved in such groundbreaking work. I probably see two or three new cases of corneal disease every month. On a larger scale, it’s a significant problem.”
Although preclinical animal studies were successful in testing the product, there are still a number of concerns among scientists, doctors and patients alike over the safety of fetal stem cells, not the least of which is a concern over the risk of teratoma (tumor) formation, in addition to immune rejection, biological contamination and genetic mutation, among other problems. It is precisely because of medical risks such as these that requests to begin similar human clinical trials in the U.S. were denied by the FDA.
Successful preclinical studies in animals are not always an accurate indication of a succesful therapy for humans, a prime example of which was the tragedy in the 1950s of thalidomide, the teratogenic effects of which were not evident in animal studies, although in humans approximately 10,000 children with severe malformities were born throughout the world to mothers who had taken thalidomide as an antiemetic to combat morning sickness during pregnancy. Precisely because of egregious preclinical failures such as the thalidomide disaster, from which victims suffered throughout their entire lives with extreme and untreatable deformities, the U.S. FDA remains justifiably cautious in its insistence upon proof of safety as well as efficacy before new therapies are allowed to advance to the human clinical trial stage.
Meanwhile, in the United Kingdom, ReNeuron has received permission from the U.K. Medicines and Healthcare Products Regulatory Agency to begin human testing of its proprietary fetal stem cell product, the cells of which have been expanded from the brains of aborted human fetuses and will now be injected directly into the affected areas of the brains of stroke victims, in the hopes of regenerating neural tissue. The clinical trials will consist of 12 patients divided into 4 groups of 3, who will be administered the fetal stem cells between 6 and 24 months after having suffered a stroke. The first injection will contain approximately 2 million fetal stem cells, with subsequent treatments being increased to 20 million fetal stem cells per injection. Follow-up will include monitoring for a year.
According to Dr. Keith Muir, who will lead the clinical trial, “If it works, as it has done in animal model systems, it may allow new nerve cells to grow, or regeneration of existing cells and actual recovery of function in patients who would not otherwise be able to regain function.”
The procedure remains highly controversial not only because of the scientific and medical concerns already cited above, but for ethical reasons as well. Nevertheless, from a purely scientific perspective, the U.S. FDA is not the only organization in which individuals have expressed their doubts and concerns about the safety of embryonic and fetal stem cells, since many scientists who work in private industry do not wish to waste money on the development of a therapy that might never yield a profit, and similarly many physicians do not wish to risk being sued for malpractice by treating their patients with a “therapy” that is known to cause tumors. Additionally, an increasingly savvy and informed patient base is also aware of the fact that adult stem cell therapy already exists and does not pose any of the risks that are inherent in embryonic and fetal stem cells, neither of which have even been tested yet as a clinical therapy for humans. Even if the fetal stem cells are proven to be capable of regenerating damaged neurological tissue in humans in the upcoming clinical trials, that alone is not enough to win approval as a therapy, since safety must also be proven. Neither safety nor efficacy by itself is a sufficient condition for therapeutic viability, though both together constitute a necessary condition. There is not much point, however, in pursuing a therapy in which the risks outweigh the benefits – especially when an alternative option, namely, adult stem cell therapy, already exists and is already in clinical use and has already been proven not to carry any risk of teratoma formation nor any of the other risks that are inherent in embryonic and fetal stem cells.
ReNeuron was originally spun-off from the Institute of Psychiatry at King’s College London in 1997. At the news of its approval to begin human clinical trials with fetal stem cells, ReNeuron’s stock jumped 174%, from £2.75 to £7.88, after having fallen precipitously from its 52 week high of nearly £20 per share in March of 2008.
