A team led by Dr Mar Tintoré, Dr Xavier Montalban and Dr Carmen Tur, from the Clinical Neuroimmunology Group at the Vall d'Hebron Research Institute (VHIR), the Department of Neurology at Vall d’Hebron University Hospital and the Multiple Sclerosis Centre of Catalonia (Cemcat), has developed Spider-MS, a new predictive model that enables individualized estimation of the course of multiple sclerosis from the very first episode suggestive of the disease. The tool, published in the journal Brain, integrates clinical, radiological and biological information to anticipate different key long-term disease events. The study was carried out in collaboration with the Epidemiology and Public Health and Neuroradiology research groups at VHIR and with the Royal Melbourne Hospital in Australia, which validated the Spider-MS model in an independent cohort.

Multiple sclerosis is a highly complex chronic disease that causes disability in a large proportion of patients and shows considerable variability between individuals, both in its course and in the mechanisms involved. While in some cases acute inflammation with relapses predominates, in others there is a gradual and continuous worsening of disability.

Over the last two decades, the availability of immunomodulatory treatments capable of modifying the course of the disease, both in terms of relapses and the development of disability, has led to significant improvements. However, the response to these therapies varies among patients and even across different manifestations of the disease, making it particularly important to anticipate its course from the earliest stages and tailor pharmacological treatment accordingly.

A tool for the individualized prediction of multiple clinical events

With the aim of facilitating prediction of disease progression, the Vall d’Hebron and Cemcat research team developed Spider-MS. To evaluate the tool, they analysed 1,180 patients followed at Cemcat from their first demyelinating episode and who were under 50 years of age at symptom onset. The patients had been followed for an average of 10 years, with data derived from clinical assessments, the Expanded Disability Status Scale (EDSS), relapse records, and magnetic resonance imaging (MRI) studies of the brain and, in some cases, the spinal cord.

The model operates using each patient's clinical, demographic and biological variables, including age, sex, the location of neurological lesions at the time of the first attack, the presence and burden of brain and spinal cord lesions, and the presence of oligoclonal bands in the cerebrospinal fluid. In addition, the model takes into account the duration of treatment with disease-modifying therapies.

Based on this information, Spider-MS is capable of independently predicting the risk of developing eight relevant clinical milestones at a given point in time (referred to as the time horizon, for example, 10 years after symptom onset), such as experiencing a second demyelinating attack, an event of progression independent (temporally distant) from relapses, or the development of new lesions on MRI. These eight risks can be represented for each patient and for each selected time horizon using a type of graph that resembles a spider's web, from which the model takes its name.

Spider-MS represents a further step complementary to the Barcelona Risk Score (BRS), developed by the same team and presented in 2025, which estimates the risk of disease progression by classifying patients into four general risk groups. According to Dr. Carmen Tur, neurologist at Vall d’Hebron University Hospital and principal investigator of the Clinical Neuroimmunology Group at VHIR and Cemcat, “Spider-MS provides more detailed information than previously published predictive models and allows us to offer an individualized estimate of several clinical events from the very first visit and simultaneously. This gives us a much more comprehensive picture of how each patient's disease is likely to evolve.”

Furthermore, the model was validated in an independent cohort of 108 patients from Melbourne (Australia), who were followed for approximately 11 years. This confirmed the predictive performance of Spider-MS in an external population.

Age and disease-modifying therapies among the factors with the greatest influence

The model's results reveal clear patterns linking the characteristics of the first episode with the subsequent course of the disease. For example, individuals who were older at the time of the first attack had a greater risk of clinical worsening, particularly of experiencing an event of progression independent (temporally distant) from relapses. By contrast, they had a lower risk of experiencing a new relapse or developing new brain lesions. Other factors associated with a poorer prognosis included spinal cord involvement during the first attack, a greater number of brain and spinal cord lesions, and the presence of oligoclonal bands in the cerebrospinal fluid.

The model also highlights the protective role of disease-modifying therapies. In particular, at the time of the first attack, after applying the model, it is possible to estimate how the hypothetical degree of exposure to moderate- or high-efficacy therapies may influence the predicted risks based on a patient's baseline characteristics, enabling the simulation of different scenarios that may, in the future, prove useful for clinical decision-making.

Work is currently underway to develop an open-access tool that will allow Spider-MS to be used in routine clinical practice. “Having a model capable of estimating the individual risk of different clinical events represents an important step towards precision medicine in multiple sclerosis. These types of tools can help better tailor patient follow-up and therapeutic decisions from the earliest stages of the disease”, concludes Dr. Mar Tintoré, Clinical Head of the Neurology/Neuroimmunology Department at Vall d’Hebron University Hospital and Cemcat, and principal investigator of the Clinical Neuroimmunology Group at VHIR.

This study was made possible thanks to a Miguel Servet contract awarded to Dr Carmen Tur by the Instituto de Salud Carlos III and to the collective effort undertaken at Cemcat since 1994, with the support of VHIR and Vall d’Hebron Hospital, both financially and in terms of human resources, to create and maintain one of the world's largest cohorts of individuals who have experienced a first episode suggestive of multiple sclerosis.