Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by loss of upper and lower motor neurons resulting in paralysis, respiratory insufficiency, difficulties speaking and swallowing, stiffness and spasticity, and muscle atrophy. Commonly known as Lou Gehrig’s disease, after the baseball player was diagnosed with it, ALS is diagnosed in an estimated 5,000 Americans each year.
Currently, ALS has a median survival time of 4.32 years and no known cure. As part of the effort to develop new therapeutic options to slow the progression of ALS, stem cell (SC) transplantation has shown potential in recent clinical trials.
In this review, Aljabri et al. examine the results of various clinical trials exploring the use of stem cell therapy as a viable therapy for ALS. Specifically, the authors identified six studies determined to have met the established criteria for review.
As part of this research, the authors examined the efficacy of SC transplantation in patients with ALS. Studies examined included a number of routes of administration, including subcutaneous, combined intrathecal and intramuscular, intravenous and intralumbar injections, and intrathecal approach. These studies all demonstrated slower decline or significant improvement as measured on the ALS Functional Rating Scale (ALSFRS-R).
While there appears to be a benefit in this application, the authors of two of the studies did not observe a significant difference in the efficacy between treatment and placebo groups after injections.
Additionally, the authors noted that all three studies using bone marrow mesenchymal stem cells (BM-MSC) demonstrated a significant decrease in the progression of disease burden and an overall slower decline in the ALSFRS-R score. On the other hand, studies that used granulocyte colony-stimulating factor (G-CSF) did not demonstrate a significant benefit.
While these results are promising, the authors point out limitations of the study that make it difficult to identify the long-term effects and long-term benefits associated with SC therapy. These limitations include short follow-up periods of either 6 or 12 months and the loss of patients during follow-up, both of which compromise the ability to determine long-term benefits and effects with fidelity.
Aljabri et al. also highlights many challenges associated with the introduction of SCs into the CNS. Among these challenges include the increased risk of AEs associated with the multiple SC injections required to deliver therapeutic doses and determining the most appropriate route of injection for therapeutic benefits.
The authors conclude that early clinical trials have made great progress in delineating the safety of SC therapy in the treatment of ALS. What remains to be determined is how effective SCs are compared to other forms of therapy. While the current data of SC therapy hold great promise, more properly designed clinical trials are needed to verify their benefit.
Source: Aljabri A, Halawani A, Bin Lajdam G, Labban S, Alshehri S and Felemban R (2021) The Safety and Efficacy of Stem Cell Therapy as an Emerging Therapy for ALS: A Systematic Review of Controlled Clinical Trials. Front. Neurol. 12:783122. doi: 10.3389/fneur.2021.783122
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