1. Stem cell therapy, why is necessary a new treatment in epilepsy?
Existing anti-epileptic drugs (AED) have limited efficiency in approximately 30 % of patients, experiencing intractable epileptic seizures, so called drug-resistant epilepsy.
Stem cell therapy may be a safe and promising new therapeutic approach for these patients, according to the results of a recently published clinical study.
2.How was the study designed?
The adult patients (18-60 years old) suffering from refractory epilepsy with frequent (>5 events per month) seizures, recruited as participants in the early phase clinical study were split in 2 groups.
They received either standard treatment with antiepileptic drugs (control group), or antiepileptic drugs plus single intravenous administration of own(target dose of 1×106cells/kg), followed by a single injection into the spinal canal (intrathecal injection) of in vitro manipulated own stem cells (target dose of 0.1×106cells/kg).
In this study were used mesenchymal stem cells collected from patient’s own bone marrow.
Mesenchymal stem cells in comparison with blood forming stem cells has the ability to give rise to different types of cells, such as bone cells (osteoblasts), cartilage cells (chondrocytes), fat cells (adipocytes) , connective stromal cells or neuronal cells.
Besides of this cells differentiation feature, mesenchymal stem cells possess unique properties to modify the immune response or the functioning of the immune system (immunomodulatory properties).
These features are the basis for the application of mesenchymal stem cells as stem cell therapy.
3. What are the results of the clinical study?
Stem cell therapy (injections of own mesenchymal stem cells) were well tolerated by all recruited patients and did not cause any severe adverse effects.
The efficacy, as the main outcome of the study was assessed by seizure frequency evaluated at 1 year time point.
3 out of 10 patients in stem cell therapy group achieved remission (no seizures for one year and more), and 5 additional patients became responders to antiepileptic drugs.
This means that 80 % of patients from cell therapy group became responders by seizure frequency, while only about 17 % (2 out of 12 patients) became responders to antiepileptic drugs in control group.
4. How to interpret these results?
Although these results seem to be encouraging it is very important to understand its limitations:
- this was an phase I, open label clinical study, meaning the investigators and patients knew the treatment which they received (antiepileptic drugs + stem cell therapy or only antiepileptic drugs)
- reduced number of participants in the study
- lack of a placebo control group, for comparison the results between patients receiving stem cell therapy and patients randomly chosen, to receive a similar product but without biological effect (placebo)
“Some beneficial effects of the combined cellular therapy on the disease status (Mini-Mental State Examination score, seizure frequency and severity, anxiety, and seizure-free remission for more than six months) were observed in the patients of cell therapy group but not in the control group,”
Further clinical studies are needed, before stem cell therapy for epilepsy could be transitioned from an experimental treatment to an approved treatment with proven efficacy.
5.Intractable epileptic seizures a problem with global impact
The prevalence of epilepsy in developed countries ranges between 4 and 10 per 1,000 individuals per year, with the greatest rates for infants and the elderly.
In developing and resource-poor countries the prevalence is much greater, according to some estimates being greater than 130 per 1000 individuals per year.
Epilepsy is a disease impacting all components of patient’s life: somatic (physical consequences), psychological component and social position.
In general, the seizures in two-thirds of people with epilepsy can be successfully controlled with currently available antiepileptic drugs.
For the other approximately 30% of patients by current anti-epileptic drugs it can’t be achieved the control of seizures.
These patients with intractable epileptic seizures represent a group with higher risk of neurologic disorders, psychological dysfunction, social stigmatization, reduced quality of life and shorter life expectancy.
Therefore, efforts to find new treatments for achieving for full seizure control, must be done especially for generalized tonic–clonic seizures.
Fedor Hlebokazov & al. “Treatment of refractory epilepsy patients with autologous mesenchymal stem cells reduces seizure frequency: An open label study” Advances in Medical Sciences, Volume 62, Issue 2, September 2017, Pages 273-279
Kenneth D.Laxer & al. “The consequences of refractory epilepsy and its treatment” Epilepsy & Behavior, Volume 37, August 2014, Pages 59-70