What happened
The CladStop study followed 204 people with relapsing multiple sclerosis (MS) at centres in Italy and Switzerland who had completed the approved two-year course of cladribine tablets. Follow-up started 24 months after the first dose and lasted 44.2 months on average. Over this time, 81 of 204 (39.7%) showed new disease activity (a relapse, new MRI activity or confirmed disability worsening); the estimated share still free of such activity was 82.8% after 12 months, 69.6% after 24 months, 63.3% after 36 months and 56.4% after 48 months. 42 people (20.6%) had a relapse (annualised relapse rate 0.06), 29.9% had new MRI activity and 7.4% had disability worsening confirmed after 6 months. 40.7% started another disease-modifying treatment, most often an anti-CD20 antibody or natalizumab. Adverse events after the course were recorded in 6 people, 2 of them serious (prostate cancer and enteritis).
| Free of disease activity (95% range) | People in the analysis | |
|---|---|---|
| Start | 100% | 204 |
| 12 months | 82.8% (77.8–88.2%) | 169 |
| 24 months | 69.6% (63.6–76.2%) | 142 |
| 36 months | 63.3% (56.9–70.3%) | 92 |
| 48 months | 56.4% (49.2–64.8%) | 33 |
Study estimates for 204 people; the shaded area shows the uncertainty (95%). They include people who started another treatment. Counting only the time before another treatment began, the figure at 48 months is 53.6%, which is similar. The study has no comparison group, and few people remain in the analysis at 48 months.
What this means for people with MS
For people who have finished cladribine tablets, these data describe what happened afterwards in routine care in two countries: disease activity stayed away for years in many people, but not in everyone, and when it returned it was mostly relapses or new MRI lesions rather than disability worsening. Follow-up continued after people started another treatment, so the figures for being free of disease activity also include time on those later treatments; the authors say they describe outcomes after completing cladribine, not the effect of cladribine alone. Among the 121 people who started no further treatment, 70.1% were estimated to be free of disease activity at 48 months, but this group was not chosen at random. The study has no comparison group, so it cannot show that cladribine caused the outcomes or compare it with other treatments; treatment decisions after the course were not random. Safety data came from routine records and stopped when another treatment began, and few people remained in the analysis at 48 months, so the later estimates are less precise. It does not justify a treatment change without review by a neurologist.
- What kind of evidence exists?
- European Journal of Neurology original article published online 30 October 2026; multicentre observational cohort
- How reliable is this source?
- Peer-reviewed open-access original article in the European Journal of Neurology, DOI 10.1111/ene.70763, PMID 42963188; full text read in PubMed Central (PMC13722574). The authors report no funding for this work; several authors declare fees from companies including the maker of cladribine tablets, outside the present work.
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