Can MUSE Stem Cells Help Amyotrophic Lateral Sclerosis (ALS)?

Amyotrophic lateral sclerosis (ALS) is a progressive disease that affects the nerve cells controlling voluntary muscle movement. As motor neurons die, patients gradually lose the ability to walk, speak, swallow, and eventually breathe. Because ALS currently has no cure and few effective drug treatments, many patients and families understandably look beyond conventional medicine for options, including stem cell therapy.

One area generating interest is a type of stem cell called MUSE cells, short for Multilineage-differentiating Stress Enduring cells. A 2023 clinical trial out of Japan tested whether MUSE cells could slow ALS progression, and the results have circulated widely in patient communities since then. This article breaks down what that study actually found, how it fits into the broader research landscape, and what questions patients should ask before considering MUSE cell therapy or other regenerative options.

What Are MUSE Cells?

MUSE cells are a type of stem cell first identified in 2010, isolated from mesenchymal stem cells found in bone marrow. What sets them apart from the other types of stem cells used in regenerative medicine is their ability to survive stress conditions and their capacity to differentiate into cells representing all three embryonic germ layers, giving them broad regenerative potential. Because they can be given intravenously and appear to home in on damaged tissue on their own, researchers have studied MUSE cells for a range of conditions, including stroke, heart attack, liver disease, and muscle degeneration.

A pharmaceutical-grade MUSE cell product called CL2020 was developed specifically to explore this therapeutic potential, including in ALS. Because MUSE cells originate from bone marrow rather than birth tissue, it’s worth understanding how bone marrow-derived stem cells compare to umbilical cord-derived options before weighing the two approaches.

Inside the 2023 MUSE Cell Study for ALS

The study in question, part of a broader wave of research into amyotrophic lateral sclerosis and stem cells, was conducted by researchers at Okayama University in Japan and published in the peer-reviewed journal Cell Transplantation in November 2023.

Study Design

Detail	Description
Patient population	5 adults with sporadic ALS (the non-inherited form, which accounts for about 90% of ALS cases)
Treatment	CL2020 MUSE cell product
Dosing	Monthly intravenous infusions for 6 months
Administration route	Intravenous (IV) only, not injected into the spine or nasal cavity
Monitoring	Blood work, cerebrospinal fluid biomarkers, and standard ALS symptom rating scales (ALSFRS-R)
Trial type	Single-center, open-label Phase 2 trial (no placebo group)

What the Results Showed

The primary goal of the trial was to assess safety, and on that front, the results were encouraging: no serious treatment-related adverse events occurred, and no patients died during the follow-up period.

The secondary goal was to evaluate whether the treatment slowed functional decline. Here, the outcomes were mixed:

Three of five patients showed a slower rate of disease progression during the six-month treatment period.

One patient showed no meaningful change.

One patient's disease progressed more rapidly.

Notably, for the patients who initially responded, the slowing effect appeared strongest while they were actively receiving monthly infusions. In the six months after treatment stopped, several patients’ decline accelerated again.

Because the study enrolled only five people and had no control group for comparison, none of these findings reached statistical significance. As the study’s own authors noted, a larger, double-blind, placebo-controlled trial is needed before any conclusions can be drawn about efficacy. The manufacturer of CL2020 had already discontinued its development program in February 2023, before the paper was even published, reportedly due to business and commercialization considerations rather than safety concerns.

Why a Study This Small Matters (and Why It Doesn't Prove Much Yet)

It’s worth understanding why researchers and clinicians are cautious about small trials like this one. With only five participants, a single patient’s outcome can swing the results dramatically. There’s no way to know whether the three patients who improved did so because of the treatment, because of natural variation in how ALS progresses from person to person, or by chance. Early-phase trials like this one are designed to answer the question “is this safe to study further?” rather than “does this work?”

This doesn’t mean the results are meaningless. Safety data from even a small trial is valuable, and modest signals of benefit can justify moving to larger studies. But it does mean the excitement around MUSE cells for ALS is currently running ahead of the evidence.

How Do Current FDA-Approved ALS Treatments Compare?

Part of the reason patients newly navigating an ALS diagnosis look toward experimental options is that approved ALS medications offer limited benefit. As of 2026, the FDA has approved several ALS therapies, more than existed just a few years ago:

Riluzole (sold as Rilutek, Tiglutik, and Exservan), the original ALS drug approved in 1995, which most large studies show extends survival by roughly two to three months.

Edaravone (Radicava and its oral form Radicava ORS), approved in 2017, which may slow functional decline in some patients, though later studies have produced mixed results.

Tofersen (Qalsody), approved in 2023, which targets a genetic mutation (SOD1) present in only about 2% of ALS cases.

Relyvrio , a combination drug approved in 2022, was later withdrawn from the U.S. and Canadian markets after a larger confirmatory trial failed to replicate its earlier benefit.

None of these treatments halts or reverses ALS, and none dramatically extends life expectancy. This treatment gap is precisely why regenerative approaches, including MUSE cells and umbilical cord-derived stem cells, continue to attract research interest and patient attention.

How Does This Compare to Umbilical Cord Stem Cell Research in ALS?

MUSE cells are not the only stem cell type being studied for ALS. Umbilical cord-derived mesenchymal stem cells, often sourced from Wharton’s jelly, have a somewhat larger and longer-running body of published research behind them.

One notable example is a case-control study conducted in Poland, which followed 67 ALS patients treated with Wharton’s jelly-derived mesenchymal stem cells, administered intrathecally (injected into the spinal fluid) every two months. Their outcomes were compared against a matched group of 67 patients from the PRO-ACT database, a large international registry of ALS clinical trial data. That study reported that median survival time roughly doubled in the treated group, and about 31% of patients showed a slower rate of disease progression, with no serious adverse reactions observed.

It’s important to note that this was a retrospective, non-randomized, compassionate-use study rather than a blinded, placebo-controlled trial, which means it carries its own limitations. Selection bias, differences in baseline health, and the lack of a true control group can all influence results in studies designed this way. Even so, having a larger patient sample and multiple published studies gives umbilical cord stem cell research a somewhat stronger evidence base than the five-patient MUSE cell trial, at least for now.

The table below summarizes the key differences:

Factor	MUSE Cell Study (2023)	Umbilical Cord MSC Study (Poland)
Patients	5	67 treated, 67 matched controls
Study type	Open-label, no control group	Retrospective case-control
Administration	Intravenous	Intrathecal
Reported outcome	Mixed; 3/5 slowed progression	Survival roughly doubled; ~31% slowed progression
Statistical significance	Not reached	Reported as favorable, though not a randomized controlled trial

Neither approach currently has the kind of large, randomized, double-blind evidence that would be required for FDA approval as a standard ALS treatment, though it’s worth reviewing what the broader body of research says about umbilical cord stem cell therapy before drawing conclusions.

What This Means for Patients Considering Stem Cell Therapy

If you or a loved one are researching stem cell therapy for ALS, a few points are worth keeping in mind:

No stem cell therapy is currently FDA-approved to treat ALS.: Understanding the relationship between stem cells and the FDA helps explain why any stem cell treatment for ALS, whether MUSE cells or umbilical cord cells, should be understood as investigational.

Safety data so far has been reassuring across multiple small trials, but reassuring safety data is not the same as proven effectiveness.

Study size and design matter. A treatment tested in five patients without a control group carries far less certainty than one tested in dozens or hundreds of patients with a comparison group.

Ask about long-term follow-up. Some early responses to stem cell treatment appear to fade once treatment stops, as seen in the MUSE cell trial, so understanding what happens after a treatment course ends is important.

Talk with your neurologist. ALS care is complex, and any decision about pursuing stem cell therapy, alongside or instead of conventional treatment, should involve the physician managing your overall care.

Clinics offering regenerative therapies, including MUSE cells, umbilical cord-derived stem cells, and exosome therapy, exist in various countries where regulatory pathways differ from the United States. R3 Stem Cell is one such provider that offers several stem cell treatment options for ALS patients, including umbilical cord stem cells and MUSE cells, at clinics across multiple countries. Patients considering this route should understand how to choose the right stem cell clinic, ask any provider for the specific research behind the product being offered, request outcome data, and confirm what monitoring and follow-up care is included.

The Bottom Line

As researchers continue to search for breakthrough treatments for ALS, the 2023 MUSE cell study offered a promising safety signal but not compelling proof of effectiveness. With only five patients and no control group, the finding that three participants experienced slower progression is interesting but far from conclusive. Larger studies on umbilical cord-derived stem cells suggest a somewhat stronger, though still preliminary, evidence base for that approach. For now, both remain investigational options rather than established ALS treatments, and patients should approach the topic with the same critical eye they’d bring to any developing area of medicine: cautious optimism, grounded in what the research can and cannot yet say.

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Can MUSE Stem Cell Therapy Help ALS Patients? 2023 Study Insights