Research, published this week in Neurology, investigates the safety level of stem cell research in individuals with Lou Gehrig’s disease, also known as amyotrophic lateral sclerosis.
Amyotrophic lateral sclerosis (ALS) is a progressive neuromuscular disease that attacks the nerves responsible for voluntary movement, slowly leading to paralysis.
The condition is fatal, normally within 2-5 years from diagnosis; the causes are not understood, and no cure has been identified.
The condition affects an estimated 3.9 per 100,000 persons.
Currently, only one drug has been approved by the United States Food and Drug Administration (FDA) for use in the treatment of ALS. The drug, called Riluzole, has been shown to slow the disease, but it offers no improvement and only extends life minimally.
Any potential avenue of investigation is followed doggedly by researchers looking for better treatments. One such avenue is stem cell research.
Previous research has demonstrated that stem cells, injected into mice, have been able to make new synaptic connections with motor neurons already in situ. They have also been shown to produce neurotrophic growth factors, which can be protective of existing cells.
Companies, such as Neuralstem, which supported the latest research covered below, set out their hopes for the future of stem cell-based treatments for ALS. According to their website, they expect the transplanted cells to:
- Graft permanently into the region where they were transplanted
- Rebuild circuitry with the patient motor neurons
- Protect patient neurons from further ravages of the disease.
A recent phase II clinical trial carried out by Dr. Jonathan D. Glass, a neurology professor at Emory University School of Medicine in Atlanta, GA, tested the safety of stem cell research for ALS patients.
The study did not concentrate on how well the procedure benefited the patient; the focus was primarily on safety.
The study used just 15 participants from three university hospitals, all of whom had received an ALS diagnosis an average of 2 years earlier. This group was split into five treatment groups, all receiving differing doses of stem cells by an increasing number of injections. The number of stem cells injected ranged from 2-16 million.
The trials were open-label – in other words, all participants knew that they were receiving stem cell therapy.
Each participant received bilateral injections between the C3 and C5 spinal regions. The final group also received injections into the lumbar and cervical cord through two additional procedures.
Over the following 9 months, the researchers measured ALS progression and, more importantly, any side effects of the treatment.
The majority of the negative side effects were pain and discomfort produced by the procedures themselves and the immunosuppressant drugs that were used. Most people tolerated the intervention well.
However, in two cases, serious complications arose. One individual developed a swelling of the spinal cord that induced pain, sensory loss, and partial paralysis; the other developed a neurological condition known as central pain syndrome.
The progression of the participant’s ALS was compared with historical records. No significant improvements were noted. However, the study was only small-scale; it is, therefore, difficult to draw solid conclusions before further investigations are conducted:
“This study was not designed, nor was it large enough, to determine the effectiveness of slowing or stopping the progression of ALS. The importance of this study is that it will allow us to move forward to a larger trial specifically designed to test whether transplantation of human stem cells into the spinal cord will be a positive treatment for patients with ALS.”
Dr. Jonathan D. Glass
Because ALS progresses so rapidly, a relatively higher relative risk is deemed acceptable if a treatment shows promise. As Dr. Glass explains: “Though there were two serious complications related to the treatment, the level of acceptable risk for treating patients with ALS, where the prognosis is poor and treatments are limited, is arguably higher than that for more benign disorders.”
Although this trial is only a small stepping stone in the right direction, now that relative safety has been demonstrated, further research can build on these findings.