Amyotrophic Lateral Sclerosis (ALS) is a degenerative disease that affects motor neurons in the brain and spinal cord, leading to muscle paralysis and death, typically within 3-5 years of onset. Despite two FDA-approved therapies, Riluzole, and Edravarone, which offer limited benefits, there remains no cure for ALS.
Considering this, researchers have turned to Mesenchymal Stem Cells (MSCs), which have shown promise in animal models and preliminary human trials for neurodegenerative diseases, including ALS.
Understanding ALS and MSC Therapy
ALS is characterized by the rapid degeneration of motor neurons, leading to muscle paralysis. The exact cause of ALS is complex and not fully understood. About 10% of cases are familial, while 90% are sporadic. Existing treatments only modestly slow disease progression and extend survival by a few months.
Stem cells, particularly MSCs, have shown potential in neuroprotection and immunomodulation. MSCs can be derived from various sources, including bone marrow, adipose tissue, embryonic tissue, cord blood, reprogrammed mature cells, and perinatal tissue. They support hematopoiesis and produce mesodermal cells. MSCs have demonstrated immunomodulatory and neurotrophic effects in animal models and early human trials.
As part of this study, Petrou et al. aimed to evaluate the safety and efficacy of repeated spinal injections of autologous MSCs in ALS patients. This open-label clinical trial included patients aged 20-70, with definite ALS diagnoses and ALS Functional Rating Scale Revised (ALSFRS-R) scores above 20. The patients received 1-4 intrathecal MSC injections at intervals of 3-6 months, with safety and tolerability as primary endpoints, and efficacy as secondary endpoints.
This trial found no serious adverse events, demonstrating the safety of repeated MSC injections. As evidence, the authors point out that, 15 out of 19 patients showed a reduction in the progression rate of their ALSFRS-R scores by more than 25% between the first and second injections, with an average improvement of 107.1%. Similar improvements were observed between subsequent injections. Thirteen patients experienced a 25% improvement in their progression rate over the entire treatment period, with an average improvement of 47.4%. Seven patients showed clinical improvement after the first transplantation, and five remained improved after the second cycle. These benefits were correlated with the intervals between the injections, suggesting that regular MSC administrations might be crucial for sustained efficacy.
Previous Studies on MSCs in ALS
Several small, open-label clinical trials have suggested that MSC treatment can be beneficial for neurological diseases, including ALS. In a phase I/II trial by the same research group, ALS patients received intrathecal and intravenous MSC injections, which were safe and showed a trend toward disease stabilization over six months. Another phase I/II and IIa trial with Brainstorm® used modified MSCs producing neurotrophic factors (MSC-NTF), showing at least a 25% improvement in disease progression, particularly in the intrathecally treated group.
Additional trials, including a randomized, placebo-controlled phase II study, demonstrated mixed results. While some trials noted improvements in a subgroup of rapid progressors, others did not show significant differences between MSC-treated and placebo groups overall. These studies highlight the need for repeated injections to maintain the benefits of MSC therapy.
Implications From the Current Study
According to Petrou et al., repeated intrathecal injections of MSCs over a longer follow-up period appears to induce significant, but short-term, clinical improvements and slow disease progression in a majority of patients. This study also reaffirmed the safety profile of MSC, with only mild and transient adverse events observed.
The study highlights the potential of MSC therapy in providing neuroprotection and slowing ALS progression. The immunomodulatory effects of MSCs, possibly reducing inflammation in the central nervous system, may also contribute to their therapeutic benefits. However, the small sample size and open-label design are limitations, necessitating larger, controlled trials to confirm these findings.
Future Directions
Petrou et al. concluded that repeated intrathecal injections of autologous MSCs are safe for ALS patients and suggest potential medium-term clinical benefits. However, larger studies are needed to confirm these findings. The consistent observation of safety and indications of efficacy across multiple cycles of treatment is encouraging, indicating that MSC therapy could slow the progression of ALS and improve patients’ quality of life.
The study’s promising results support the continued exploration of MSC therapy for ALS. The authors call for future trials to focus on optimizing the timing and frequency of MSC injections to maximize clinical benefits. Larger, controlled studies are essential to validate these findings and potentially establish MSC therapy as a viable treatment option for ALS. By addressing the unmet needs in neuroprotection and immunomodulation, MSC therapy holds the potential of improving the quality of life and survival for ALS patients.
Source: Panayiota Petrou, Ibrahim Kassis, Nour Eddine Yaghmour, Ariel Ginzberg, Dimitrios Karussis. A phase II clinical trial with repeated intrathecal injections of autologous mesenchymal stem cells in patients with amyotrophic lateral sclerosis. Front. Biosci. (Landmark Ed) 2021, 26(10), 693–706. https://doi.org/10.52586/4980
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