The management of Multiple Sclerosis (MS) has undergone a seismic shift over the last two decades. With the advent of a wide array of disease-modifying therapies (DMTs), neurologists have moved from a "wait and see" approach to an aggressive, early-intervention strategy. However, a major, prospective study published in Neurology Open Access from the MultipleMS cohort has highlighted a sobering reality: while modern, high-efficacy drugs are exceptional at silencing acute inflammation, they may be hitting a wall when it comes to the long-term, smoldering progression of the disease.
The two-year study of 509 newly diagnosed patients suggests that while B-cell-depleting therapies and high-efficacy drugs significantly reduce clinical relapses and brain lesion accumulation compared to oral alternatives, these benefits do not necessarily translate into better disability outcomes within the first 24 months of treatment.
Main Facts: The Efficacy Dichotomy
The MultipleMS study, a robust real-world observation spanning seven European countries, sought to clarify how different therapeutic classes affect the dual nature of MS: the acute inflammatory "flare-up" phase and the silent, chronic progression phase.
The research team, led by Fredrik Piehl, MD, PhD, of the Karolinska Institute in Stockholm, categorized 509 treatment-naive patients into five distinct groups: those on injectable platform therapies, oral platform therapies, high-efficacy therapies, B-cell-depleting agents, and an untreated control group.
The primary finding was a clear hierarchy in suppressing the "visible" markers of MS. Patients treated with B-cell-depleting drugs (such as ocrelizumab or ofatumumab) and other high-efficacy therapies demonstrated a significantly lower incidence of clinical relapses compared to those on oral platform drugs. Furthermore, MRI scans confirmed that these patients saw a greater reduction in T2 lesion volume—a classic marker of inflammatory brain activity.
Yet, when researchers looked at the Expanded Disability Status Scale (EDSS)—the gold standard for measuring patient physical function—the benefits of these potent drugs vanished. At the two-year mark, there was no statistically significant difference in disability scores between the high-efficacy groups and the oral medication groups. This discrepancy suggests that while modern medicine has mastered the "firefighting" aspect of MS, it is still struggling to extinguish the "smoldering" embers of neurodegeneration that drive long-term physical decline.
Chronology of the Study and Patient Cohort
The MultipleMS study represents one of the most comprehensive real-world tracking efforts in recent years. Enrollment focused exclusively on newly diagnosed patients who had not previously been exposed to DMTs, providing a "clean slate" for observation.
- Baseline Profile: The cohort consisted of 509 patients with a mean age of 33. Women comprised 63.9% of the participants, and 89% were diagnosed with relapsing-remitting MS (RRMS). The median EDSS score at the start of the study was 1.5, reflecting a mild level of initial disability.
- The Selection Bias: A critical element of the study was the acknowledgment of "treatment selection bias." Patients starting on high-efficacy or B-cell-depleting therapies already had higher baseline EDSS scores (2.0) compared to those starting on injectables (1.0). This indicates that clinicians were already identifying "high-risk" patients and opting for more aggressive therapy immediately, which makes the lack of long-term disability divergence even more striking.
- Two-Year Follow-up: By the end of the 24-month window, data showed high retention rates for the most potent therapies; approximately 90% of patients on B-cell-depleting drugs remained on their original treatment, compared to only 50–70% for other groups. This high adherence underscores the perceived benefit of these treatments by both patients and providers, despite the lack of measurable improvement in disability scores.
Supporting Data: Biomarkers and Brain Metrics
To look beyond clinical symptoms, the team analyzed two specific blood-based biomarkers: serum neurofilament light (NfL) and serum glial fibrillary acidic protein (GFAP). These markers provide a window into the biological mechanisms of the central nervous system.
NfL: The Inflammatory Messenger
NfL is widely recognized as a proxy for axonal injury and inflammatory disease activity. As expected, the study found that all treatment groups showed a suppression of NfL levels, correlating with the successful reduction of relapses and new MRI lesions.
GFAP: The Progressive Enigma
The data regarding GFAP—a marker associated with astroglial activation and chronic damage—provided a more nuanced, and perhaps troubling, result. Levels of GFAP decreased modestly across the board. However, the study observed that those on oral therapies actually saw larger reductions in GFAP compared to those on B-cell-depleting or high-efficacy therapies.
This is a paradoxical finding. Researchers hypothesized that higher levels of GFAP in the high-efficacy groups might reflect a biological "persistence" of chronic inflammation that is not being adequately addressed by current B-cell-focused therapies. It suggests that while the drugs are hitting the B-cells (the primary drivers of relapses), they may be leaving other pathways—such as microglia-driven, compartmentalized inflammation—largely untouched.
Official Responses and Expert Analysis
Dr. Fredrik Piehl, in his summary of the findings, emphasized the complexity of the clinician’s role. "The treatment groups already differed in important patient characteristics, suggesting that doctors were to some extent selecting treatments based on the individual patient," he noted.
Dr. Piehl’s stance is one of cautious optimism. While he acknowledges the plateau in disability scores, he points out that a two-year window is relatively short for a disease that can span decades. "Some treatments were linked to fewer attacks and fewer MRI changes, and by following this group for several more years, we will be able to determine whether differences emerge over the longer term."
Providing an external perspective, Carmen Tur, MD, PhD, of the Multiple Sclerosis Centre of Catalonia, authored an accompanying editorial in Neurology. Her assessment was more critical of current clinical paradigms.
"These results point toward a poor ability of high-efficacy therapies and B-cell-depleting therapies to reduce chronic inflammation despite their strong effect against acute inflammation," Dr. Tur wrote. She argued that the field is witnessing a "decoupling" of disease activity. The inflammation that causes relapses appears to be a distinct biological process from the "progression independent of relapse activity" (PIRA) that characterizes long-term disability.
Implications: The Unmet Need in MS Care
The implications of the MultipleMS study are far-reaching for neurologists, pharmaceutical researchers, and, most importantly, patients.
A Pivot in Drug Development
The failure of current high-efficacy drugs to move the needle on disability scores suggests that the industry may need to shift its focus. If B-cell depletion is the current "ceiling" for anti-inflammatory treatment, the next generation of drugs must target different, more stubborn mechanisms.
Dr. Tur highlighted this in her editorial, noting that the emergence of Bruton tyrosine kinase (BTK) inhibitors and anti-CD40 ligand monoclonal antibodies represents a new frontier. These agents are designed to cross the blood-brain barrier more effectively and target the microglia—the brain’s resident immune cells—that are thought to drive the chronic, smoldering inflammation associated with progressive disability.
Re-evaluating the "Early Aggressive" Strategy
The data supports the concept that current treatments are highly effective at preventing the "noisy" part of MS—the relapses that lead to immediate emergency room visits and steroid treatments. However, the lack of divergence in EDSS scores after two years forces a re-evaluation of how "success" is defined. If a patient is relapse-free but still accumulating disability, the current high-efficacy therapy cannot be considered a total success.
The Challenge of Time
For the medical community, the primary takeaway is that disability is a "delayed phenomenon." It is the culmination of years of sub-clinical injury. As the study authors noted, measuring disability in a comprehensive way remains a significant challenge. Future research must look at long-term atrophy rates and neurodegenerative biomarkers over 5, 10, or 15 years to see if the "early intervention" strategy truly pays dividends in the form of delayed nursing home admission or preserved mobility in later life.
The Patient Perspective
For patients, the message is one of nuance. While the fear of a relapse is a major driver for choosing high-efficacy treatment, the study suggests that these therapies are not a "cure-all." Patients should have informed conversations with their neurologists about the distinction between "preventing attacks" and "preventing progression."
As the MultipleMS cohort continues to be monitored, the medical community waits with bated breath. If, after five or ten years, the gap in disability scores begins to widen, it would validate the current aggressive treatment paradigm. If, however, the gap remains closed, it will serve as a definitive call to action to move beyond current B-cell-depletion strategies and find therapies that address the hidden, smoldering fire of chronic neuroinflammation.
In the battle against MS, the first shots have been fired, and the initial inflammatory battles are being won—but the war against progressive disability continues on a front that medicine has yet to fully map.
