Clemastine fumarate accelerates accumulation of disability in progressive multiple sclerosis by enhancing pyroptosis
Joanna Kocot, … , Steven M. Holland, Bibiana Bielekova
Joanna Kocot, … , Steven M. Holland, Bibiana Bielekova
Published May 15, 2025
Citation Information: J Clin Invest. 2025;135(10):e183941. https://doi.org/10.1172/JCI183941.
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Research Article Immunology Neuroscience

Clemastine fumarate accelerates accumulation of disability in progressive multiple sclerosis by enhancing pyroptosis

Abstract

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the CNS. Clemastine fumarate, the over-the-counter antihistamine and muscarinic receptor blocker, has remyelinating potential in MS. A clemastine arm was added to an ongoing platform clinical trial, targeting residual activity by precision, biomarker-guided combination therapies of multiple sclerosis (TRAP-MS) (ClinicalTrials.gov NCT03109288), to identify a cerebrospinal fluid (CSF) remyelination signature and to collect safety data on clemastine in patients progressing independently of relapse activity (PIRA). The clemastine arm was stopped per protocol-defined criteria when 3 of 9 patients triggered individual safety stopping criteria. Clemastine-treated patients had significantly higher treatment-induced disability progression slopes compared with the remaining TRAP-MS participants. Quantification of approximately 7,000 proteins in CSF samples collected before and after clemastine treatment showed significant increases in purinergic signaling and pyroptosis. Mechanistic studies showed that clemastine with sublytic doses of extracellular adenosine triphosphate (ATP) activates inflammasome and induces pyroptotic cell death in macrophages. Clemastine with ATP also caused pyroptosis of induced pluripotent stem cell–derived human oligodendrocytes. Antagonist of the purinergic channel P2RX7, which is strongly expressed in oligodendrocytes and myeloid cells, blocked these toxic effects of clemastine. Finally, reanalysis of published single-nucleus RNA-Seq (snRNA-Seq) studies revealed increased P2RX7 expression and pyroptosis transcriptional signature in microglia and oligodendrocytes in the MS brain, especially in chronic active lesions. The CSF proteomic pyroptosis score was increased in untreated MS patients, was higher in patients with progressive than relapsing-remitting disease, and correlated significantly with the rates of MS progression. Collectively, this identifies pyroptosis as a likely mechanism of CNS injury underlying PIRA even outside of clemastine toxicity.

Authors

Joanna Kocot, Peter Kosa, Shinji Ashida, Nicolette A. Pirjanian, Raphaela Goldbach-Mansky, Karin Peterson, Valentina Fossati, Steven M. Holland, Bibiana Bielekova

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Figure 1

CLM-induced changes in disability, metabolism, and inflammatory markers.

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CLM-induced changes in disability, metabolism, and inflammatory markers....
(A) Clinical safety was monitored by a continuous, machine-learning derived CombiWISE scale (range 0–100) that correlates strongly with EDSS (range 0–10). R-squared in Linear Regression was used. n = 935. (B) A minimum of 4 visits on stable therapy spanning at least 18 months is required to measure baseline (blue) CombiWISE slope. On-therapy CombiWISE slope (orange) is calculated based on 6-months follow-up data collected after therapy initiation. (C) Three out of 9 patients on CLM therapy triggered safety criteria, in contrast to none of the 63 patient-specific treatments of 6 other TRAP-MS therapies; P value of probability of this occurrence was based on χ2 test. (D) Progression CombiWISE slopes at baseline (B) and therapy (T) were compared between CLM arm (n = 9) and all other 6 TRAP-MS therapies (n = 63). Black horizontal line represents median value of the group. Red color indicates 3 patients that triggered safety-stopping criteria treatment slope exceeding 5× baseline slope. Displayed P value was generated from 2-sided unpaired Wilcoxon’s rank test comparing therapy-induced change in CombiWISE slope between the CLM arm and all other therapies. CLM induced increase of weight (E), LDL cholesterol (F), and total cholesterol (G) levels between baseline and treatment and these changes showed strong association as seen on example of weight change versus LDL cholesterol change (H). R-squared in linear regression was used. Furthermore, CLM induced increase of inflammatory biomarker CRP (I). Lipid panel was an optional laboratory test, and the results are missing for 1 patient. Blue line in H represents linear regression line; gray dashed line in D–G and I represents 0 change. The lower and upper hinges of the boxplots correspond to the first and third quartiles (the 25th and 75th percentiles). The upper and lower whiskers extend from the hinge to the largest and smallest value, respectively.