ECTRIMS 2025: Long-term benefits seen with Mavenclad use in MS
Most patients remain free of confirmed disability worsening after 4 years
Most people with relapsing forms of multiple sclerosis (MS) given Mavenclad (cladribine) did not experience confirmed disability progression for at least four years after starting on the approved therapy, according to new Phase 4 trial data.
The results come from the CLARIFY-MS (NCT03369665) and MAGNIFY-MS (NCT03364036) trials, which tested Mavenclad in a short course for the first two years and then tracked outcomes for up to two additional years in their extension studies. Phase 4 trials like these, conducted after a medication is approved for public use, are surveillance studies typically used to monitor long-term safety, track any side effects, and evaluate effectiveness over time in real-world conditions.
Additionally, a separate analysis from the same trials indicated that Mavenclad may also limit disability progression that occurs independently of relapses, with 9 of 10 patients remaining free of such events after four years.
Mavenclad’s developer EMD Serono (known as Merck KGaA outside the U.S. and Canada) presented the new data in a pair of posters at the 41st Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS), held Sept. 24-26, in Barcelona, Spain, and online.
“As the only high-efficacy short-course oral treatment, Mavenclad has demonstrated sustained benefits across a variety of outcomes — extending beyond relapses and MRI — without requiring continuous immunosuppression,” Alex Kulla, PhD, senior vice president and global head of the neurology and immunology medical unit for the healthcare business of Merck KGaA, said in a company press release.
Mavenclad is a short-course oral treatment that destroys immune cells involved in MS inflammation. The therapy is approved for relapsing forms of MS, and is taken in two courses over two years, requiring no more than 20 treatment days across the entire period.
The medication has been approved in the U.S. since 2019, and is also available in more than 80 countries.
Phase 4 trials tracked over 750 patients given Mavenclad after its approval
The new analyses cover data from 752 people who took part in CLARIFY-MS or MAGNIFY-MS. The participants received Mavenclad treatment courses in the first two years, and were then followed for two additional years in the extension studies, where they did not receive treatment.
In one poster at ECTRIMS, titled Long-Term Effect of Cladribine Tablets on Disability Progression and Improvement: Insights from Pooled Analyses of CLARIFY-MS and MAGNIFY-MS Studies,” researchers evaluated long-term disability outcomes, as assessed mainly by the Expanded Disability Status Scale (EDSS).
The results showed that most patients (64.2%) had stable disease, with EDSS scores remaining unchanged over the four years. Another 15.4% of patients experienced a sustained decrease in EDSS scores, indicating less severe disability.
The comprehensive data presented at ECTRIMS 2025 reinforces [Mavenclad’s] role in delivering durable, effective care for individuals with [relapsing MS] — supporting them from early diagnosis through later stages of life.
Patients who experienced disability improvement, or no worsening, tended to be age 50 or younger and previously untreated, “supporting the early use of cladribine tablets,” the researchers wrote.
Over the four years of follow-up, a total of 16.6% of patients experienced an increase in EDSS scores that was sustained for at least six months — a measure called six-month confirmed disability progression, or CDP.
“The comprehensive data presented at ECTRIMS 2025 reinforces [Mavenclad’s] role in delivering durable, effective care for individuals with [relapsing MS] — supporting them from early diagnosis through later stages of life,” Kulla said.
About 10% of patients had progression independent of relapses
People with relapsing forms of MS may have disability progression due to poor recovery from a relapse. But some individuals also may experience progression independent of relapse activity, known as PIRA, in which disability worsens even though the patient has not experienced a relapse.
Rates of PIRA were analyzed in a separate poster, titled “Cladribine Tablets Show Low 4-Year PIRA Rates in MS: Insights from Pooled Analyses of CLARIFY-MS and MAGNIFY-MS Studies.”
These results showed that slightly more than 10% of patients experienced PIRA during follow-up, while 6% experienced relapse-associated worsening, or RAW. Statistical analyses indicated that patients who were older than 40 were more likely to experience PIRA compared with younger patients.
“These findings demonstrate long-term control of both inflammatory and noninflammatory components of disability accumulation and disease progression” in a large group of Mavenclad-treated patients, the researchers wrote.
According to EMD Serono, the results “highlight the potential of Mavenclad to reduce neurodegeneration and neuroinflammation beyond established clinical efficacy outcomes in [relapsing] MS.”
Note: The Multiple Sclerosis News Today team is providing live coverage of the 41st Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) Sept. 24-26. Go here to see the latest stories from the conference.
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