XVII Post-ECTRIMS Meeting: Review of the New Developments Presented at the 2024 ECTRIMS Congress (I)

Introduction: The XVII edition of the post-European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) meeting was held on 4-5 October 2024 in Madrid. This event was attended by Spanish neurologists specialized in multiple sclerosis (MS), who presented a summary of the most relevant advances discussed at the ECTRIMS congress, held days before in Copenhagen. Aim: To present new developments in neurodegeneration and progression, the prodromal phase and diagnosis, the clinical use of biomarkers and neuroimaging, as well as the current role of patient-reported outcomes and digital monitoring. Highlights on the risk of infections and comorbidities in MS are also summarized. Content and Conclusions: In active MS lesions, there is no correlation between the myeloid cell phenotype and remyelination, while memory astrocytes, regulated by the CLEC16A gene, are present in chronic active lesions. Gray matter atrophy is associated with disability and progression independent of relapses, whereas cervical spinal cord atrophy predicts the prognosis of progressive forms and may lead to earlier diagnosis. Healthcare resource utilization increases in the years preceding the first demyelinating event, and although prodromal symptoms are highly variable, they are useful in identifying risk factors for the disease. The new McDonald criteria will facilitate the diagnosis of MS in patients with a radiologically isolated syndrome. Glial fibrillary acidic protein complements neurofilaments, and both biomarkers could soon be standardized for use in clinical practice; paramagnetic rim lesions and slowly expanding lesions are promising imaging markers. In another area, patient-reported health outcomes are valuable, although they are subject to selection bias and the need to define boundaries for their use. Finally, the risk of infections increases before diagnosis and may worsen with certain treatments. Comorbidities in MS should be managed as an integral part of disease management.