People who experience a first attack of multiple sclerosis (MS)-like disease are less likely to experience long-term disability progression if they start treatment within the first few months, a new study reports. "When it comes to MS treatment, the earlier the better," Alvaro Cobo-Calvo, MD, PhD, co-author of the study at the Multiple Sclerosis Center of Catalonia and the Autonomous University of Barcelona in Spain, said in a press release from the American Academy of Neurology. "Our study found that starting treatment within six months after the first symptoms is associated with a lower risk of disability over time," Cobo-Calvo added. The study, "Association of Very Early Treatment Initiation With the Risk of Long-Term Disability in Patients With a First Demyelinating Event," was published in Neurology. Most people with MS initially develop relapsing-remitting disease (RRMS), which is defined by relapses or flares where symptoms worsen, followed by periods of remission where symptoms ease or disappear entirely. As the disease progresses over time, many people with RRMS will transition to secondary progressive MS (SPMS), a form of the disease in which symptoms gradually worsen over time independent of relapse activity. Clinically isolated syndrome. A first attack of MS-like symptoms is known as clinically isolated syndrome or CIS. Technically, CIS is not considered to be a true form of MS, as a person typically needs to experience more than one attack to confirm the diagnosis. (That's where the "multiple" comes from in "multiple sclerosis.") While many people with CIS will go on to develop RRMS, some won't. It's been established that giving MS disease-modifying treatments to people with CIS may decrease the likelihood of more disease events in the future. However, the best timing for beginning treatment in CIS remains debatable. In this study, scientists analyzed data for 580 people who experienced a first attack of MS-like symptoms between 1994 and 2021. At the time of fist symptoms, patients were between ages 16 and 50. All of the patients received treatment and were followed for an average of more than a decade. For their analysis, the researchers divided the patients into three groups based on when they had started treatment. The first group included 194 patients who had started on treatment within six months of the initial disease attack. The second group had 192 patients who started treatment between six and 16 months after the attack, while the 194 patients in the third group started treatment more than 16 months after the first attack. Significant risk reduction. The scientists constructed statistical models to compare the risk of worsening disease in these three groups. Results showed that, compared with patients who started treatment more than 16 months after the attack, patients who started on early treatment within six months were about 45% less likely to have moderate disability. This degree of disability was defined as a score of 3 or higher on the Expanded Disability Status Scale (EDSS), where higher scores in a range of zero to 10 indicate higher disability. A total of 23% of patients in the early treatment group reached that score, compared with nearly half (43%) of those in the late treatment group. These patients also were about 60% less likely to transition to SPMS, with 7% of patients given early treatment developing the progressive form over the follow-up, compared with 23% of those given treatment after 16 months. "We showed that treatment initiation at very early stages is associated with a reduction in the risk of long-term disability accrual in patients with" a first attack of MS-like disease, the scientists concluded. Patients who received treatment within six months also were 50% more likely to have stable disability one year after the attack and had a significantly lower rate of disability progression. Patient-reported measures of disability also showed a significant difference between the groups. "Altogether, our results support the robustness and effectiveness of very early treatment to halt long-term disability progression, and stress that earlier detection and treatment is encouraged," Cobo-Calvo said. The researchers noted this study focused only on patients who experienced a first CIS attack between ages 16 and 50, so the results may not be applicable to patients who experience CIS with onset later in life.