Efficacy and safety of low-dose IL-2 as an add-on therapy to riluzole (MIROCALS): a phase 2b, double-blind, randomised, placebo-controlled trial
- PMID: 40354799
- DOI: 10.1016/S0140-6736(25)00262-4
Efficacy and safety of low-dose IL-2 as an add-on therapy to riluzole (MIROCALS): a phase 2b, double-blind, randomised, placebo-controlled trial
Abstract
Background: Amyotrophic lateral sclerosis (ALS) is a life-threatening disease characterised by progressive loss of motor neurons with few therapeutic options. The MIROCALS study tested the hypothesis that low-dose interleukin-2 (IL-2LD) improves survival and function in ALS.
Methods: In this randomised, double-blind, placebo-controlled trial, male and female riluzole-naive participants, with either a possible, laboratory-supported probable, probable, or definite ALS diagnosis (revised El Escorial criteria), aged 18-76 years, with symptom duration of 24 months or fewer, and slow vital capacity of 70% or more, underwent a riluzole-only 12-18 week run-in period before randomisation in a 1:1 ratio to either 2 million international units (MIU) IL-2LD or placebo by subcutaneous injection daily for 5 days every 28 days over 18 months. The primary endpoint was survival at 640 days (21 months). Secondary outcomes included safety, ALS Functional Rating Scale-Revised (ALSFRS-R) score, and biomarker measurements including regulatory T-cells (Tregs), cerebrospinal fluid (CSF)-phosphorylated-neurofilament heavy-chain (CSF-pNFH), and plasma and CSF-chemokine ligand 2 (CCL2). The primary endpoint analysis used unadjusted log-rank and Cox's model adjusted analyses using pre-defined prognostic covariates to control for the disease and treatment response heterogeneity. The study was 80% powered to detect a two-fold decrease in the risk of death by the log-rank test in the intention-to-treat (ITT) population, including all randomly allocated participants. MIROCALS is registered with ClinicalTrials.gov (NCT03039673) and is complete.
Findings: From June 19, 2017, to Oct 16, 2019, 304 participants were screened, of whom 220 (72%) met all criteria for random allocation after the 12-to-18-week run-in period on riluzole. 136 (62%) of participants were male and 84 participants (38%) were female. 25 (11%) of the 220 randomly allocated participants were defined as having possible ALS under El Escorial criteria. At the cutoff date there was no loss to follow-up, and all 220 patients who were randomly allocated were documented as either deceased (90 [41%]) or alive (130 [59%]), so all participants were included in the ITT and safety populations. The primary endpoint unadjusted analysis showed a non-significant 19% decrease in risk of death with IL-2LD (hazard ratio 0·81 [95% CI 0·54-1·22], p=0·33), failing to demonstrate the expected two-fold decrease in risk of death. The analysis of the primary endpoint adjusted on prognostic covariates, all measured at time of random allocation, showed a significant decrease of the risk of death with IL-2LD (0·32 [0·14-0·73], p=0·007), with a significant treatment by CSF-pNFH interaction (1·0003 [1·0001-1·0005], p=0·001). IL-2LD was safe, and significantly increased Tregs and decreased plasma-CCL2 at all timepoints. Stratification on CSF-pNFH levels measured at random allocation showed that IL-2LD was associated with a significant 48% decrease in risk of death (0·52 [0·30-0·89], p=0·016) in the 70% of the population with low (750-3700 pg/mL) CSF-pNFH levels, while in the 21% with high levels (>3700 pg/mL), there was no significant difference (1·37 [0·68-2·75], p=0·38).
Interpretation: With this treatment schedule, IL-2LD resulted in a non-significant reduction in mortality in the primary unadjusted analysis. However, the difference between the results of unadjusted and adjusted analyses of the primary endpoint emphasises the importance of controlling for disease heterogeneity in ALS randomised controlled trials. The decrease in risk of death achieved by IL-2LD therapy in the trial population with low CSF-pNFH levels requires further investigation of the potential benefit of this therapy in ALS.
Funding: European Commission H2020 Programme; French Health Ministry PHRC2014; and Motor Neurone Disease Association.
Copyright © 2025 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.
Conflict of interest statement
Declaration of interests All authors or their institutions received support for the present manuscript from the EU H2020 programme (number 633413) and from at least one of the following: the French Health Minister, the Motor Neurone Disease (MND) Association, the Association Française contre les Myopathies, the Association pour La Recherche sur SLA (ARSLA), MND Scotland, the My Name'5 Doddie Foundation, or the Alan Davidson Foundation. GB declares a license for MIROCALS data for regulatory purposes; and patent numbers WO2012123381A1, WO2021176044 A1, and WO2024121173A1. PNL declares patents (numbers WO2021176044 A1 and WO2024121173A1); and a license for MIROCALS data; and participation on a data, safety, and monitoring board for Novartis. TT, AM, ML, CG, and JK declare patents (numbers WO2021176044 A1 and WO2024121173A1); and a license for MIROCALS data. AM declares contracts from My Name'5 Doddie Foundation, Target ALS, NIHR UCL Biomedical Research Centre, LifeArc, Medical Research Council, NIH and Motor Neurone Disease Association; consulting fees from Pfizer, Novartis, LifeArc, Accure, Trace Neuroscience; and a licence to Biogen. AAK declares contracts with the Motor Neurone Disease Association (MNDA), National Institute for Health and Care Research (NIHR) Maudsley Biomedical Research Centre, Amyotrophic Lateral Sclerosis (ALS) Association Milton Safenowitz Research Fellowship, Darby Rimmer MND Foundation, LifeArc, and the Dementia Consortium; equipment by NIHR Maudsley Biomedical Research Centre; and consulting fees from the UK National Endowment for Science, Technology and the Arts (NESTA). SA declares honoraria from Alexion, Argenx, Janssen, UCB, Roche, Sanofi, Pfizer, Biogen, Alnylam, AstraZeneca, Amicus, Novartis, and Laboratoire français du fractionnement et des biotechnologies. EB declares contracts with the ARSLA; consulting fees from Biogen; honoraria from Elsevier, Amylyx, Roche, Sanofi, and Effik; expert testimony for the Haute Autorité de Santé; support for attending meetings or travel from Effik and Zambon; and scientific committee membership for the ARSLA (non-financial interest). J-CC declares contracts with the Agence Nationale de la recherche (ANR), European Union Joint Programme - Neurodegenerative Disease Research (JPND), and Paris Brain Institute (ICM); consulting fees from Iregene, Alzprotect, Ferrer, Biogen, Servier, and UCB; support for attending meetings or travel from the International Movement Disorders Society; and participation on a data and safety monitoring board for Servier. PCou declares contracts with the ARSLA, ANR (PrevDemAls), ANR French German Cohort ALS (FCGals), and ANR (BMAALS); consulting fees from Zambon, Effik, Amylyx, Mitsubishi, and Biogen; lecture fees for Biogen, Zambon, and Mitsubishi; participation on advisory boards for Masitinib trial (ABScience) and MIROCALS; and position as chairman of the rare diseases network for ALS and other motorneuron diseases in France. JE is a co-opted trustee at MNDA. GHG declares contracts from My Name'5 Doddie Foundation. CJMD declares consulting fees from Amylyx; and participation on a data and safety monitoring board or advisory board for Verge and Novartis. NS declares a leadership role as the CEO and co-founder of BioCorteX. PJS declares contracts from US Department of Defense, Wolfson Foundation Equipment Award, My Name'5 Doddie Foundation, NIHR Sheffield Biomedical Research Centre, LifeArc, Medical Research Council, NIHR EXPERTS-ALS, and the Motor Neurone Disease Association; a license for MIROCALS data; and patents (numbers WO2021176044 A1 and WO2024121173A1). M-HS declares lecture fees from Zambon; support for attending meetings or travel from Effik-Italfarmaco; and membership of scientific advisory boards from Amylyx, Biogen, and Zambon. HZ declares contracts from the Swedish Research Council (#2023–00356; #2022–01018, and #2019–02397), the EU H2020 programme under grant agreement number 101053962, Swedish State Support for Clinical Research (#ALFGBG-71320), the US Alzheimer Drug Discovery Foundation (ADDF; #201809–2016862), the AD Strategic Fund, and the Alzheimer's Association (#ADSF-21–831376-C, #ADSF-21–831381-C, #ADSF-21–831377-C, and #ADSF-24–1284328-C), the Bluefield Project, Cure Alzheimer's Fund, the Olav Thon Foundation, the Erling-Persson Family Foundation, Stiftelsen för Gamla Tjänarinnor, Hjärnfonden, Sweden (#FO2022–0270), the EU Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 860197 (MIRIADE), the European Union Joint Programme – Neurodegenerative Disease Research (JPND2021–00694), the NIHR University College London (UCL) Hospitals Biomedical Research Centre, and the UK Dementia Research Institute at UCL (UKDRI-1003); consulting fees from AbbVie, Acumen, Alector, Alzinova, ALZPath, Amylyx, Annexon, Apellis, Artery Therapeutics, AZTherapies, Cognito Therapeutics, CogRx, Denali, Eisai, LabCorp, Merry Life, Nervgen, Novo Nordisk, Optoceutics, Passage Bio, Pinteon Therapeutics, Prothena, Red Abbey Labs, reMYND, Roche, Samumed, Siemens Healthineers, Triplet Therapeutics, and Wave; lectures for Alzecure, BioArctic, Biogen, Cellectricon, Fujirebio, Lilly, Novo Nordisk, Roche, and WebMD; membership of scientific advisory boards or roles as a consultant for AbbVie, Acumen, Alector, Alzinova, ALZPath, Amylyx, Annexon, Apellis, Artery Therapeutics, AZTherapies, Cognito Therapeutics, CogRx, Denali, Eisai, LabCorp, Merry Life, Nervgen, Novo Nordisk, Optoceutics, Passage Bio, Pinteon Therapeutics, Prothena, Red Abbey Labs, reMYND, Roche, Samumed, Siemens Healthineers, Triplet Therapeutics, and Wave; chair of the Alzheimer's Association Global Biomarker Standardization Consortium and chair of the IFCC WG-BND; and being co-founder of Brain Biomarker Solutions in Gothenburg AB (BBS), which is a part of the GU Ventures Incubator Programme. AA-C declares contracts with the MRC, NIHR and Darby Rimmer Foundation; licence for MIROCALS data; consulting fees from Amylyx, Apellis, Biogen, Brainstorm, Clene Therapeutics, Cytokinetics, GenieUs, GSK, Lilly, Mitsubishi Tanabe Pharma, Novartis, OrionPharma, Quralis, Sano, and Sanofi; and a patent (number WO2024121173A1). PCor declares honoraria from Amylyx, Biogen, Cytokinetics, Effik, Ferrer, Mitsubishi, Tanabe,QurALIs Vectory, and Zambon. CAMP, H-PP, PK, MDMA, SMB, SB, WC, VD, RD, CD, AD, FE, M-CF, A-MG, AH, RJ-M, IK, GL, NLF, NP, FS, JSr, JSv, NV, AV, OY, CMS, SSD, CMu, CMa, HH, and BA declare no competing interests.
Publication types
MeSH terms
Substances
Associated data
LinkOut - more resources
Full Text Sources
Medical
Research Materials
Miscellaneous
