Idebenone does not inhibit disability progression in primary progressive MS.

Area of Science:

• Neuroscience
• Immunology
• Biochemistry

Background:

• Multiple sclerosis (MS) is a chronic, immune-mediated neurodegenerative disorder affecting the central nervous system (CNS).
• Current MS therapies focus on inflammation, not mitochondrial dysfunction or axonal loss.
• Primary progressive MS (PPMS) presents unique challenges in understanding and treating neurodegeneration.

Purpose of the Study:

• To evaluate if idebenone can inhibit mitochondrial dysfunction and reduce disability accumulation in PPMS.
• To explore cerebrospinal fluid (CSF) biomarkers for insights into PPMS pathogenesis.
• To assess idebenone's impact on specific CSF biomarkers related to mitochondrial damage and axonal loss.

Main Methods:

• A double-blind, placebo-controlled Phase I/II clinical trial (IPPoMS) was conducted.
• The study utilized an adaptive design with a baseline-versus-treatment paradigm.
• Primary outcome was change in the Combinatorial Weight-Adjusted Disability Score (CombiWISE); secondary outcomes included traditional scales and brain volume; exploratory outcomes involved CSF biomarkers (GDF15, lactate, NFL, etc.).

Main Results:

• Idebenone was well-tolerated but did not significantly inhibit disability progression or CNS tissue destruction.
• CSF GDF15 levels, a biomarker for mitochondrial damage, were elevated in PPMS patients compared to age-adjusted healthy volunteers.
• Idebenone treatment did not alter CSF GDF15 levels, indicating no inhibition of intrathecal mitochondrial damage.

Conclusions:

• Mitochondrial dysfunction, exceeding normal aging, is prevalent in most PPMS patients.
• This dysfunction, as measured by age-adjusted CSF GDF15, is not ameliorated by idebenone treatment.
• The study highlights the presence of mitochondrial dysfunction in PPMS but identifies idebenone as ineffective in targeting it.