Trial results for the Oral Cladribine B-cell Study in Multiple Sclerosis were posted on ClinicalTrials.gov on 2026-02-04, indicating a median 62.8% reduction in class-switched memory B cells from baseline to Week 96 in participants treated with cladribine.
Background
Multiple Sclerosis (MS) is a chronic, autoimmune disease that affects the brain and spinal cord, leading to a range of neurological symptoms. Current treatments aim to modify the disease course, reduce relapse rates, and slow disability progression. Cladribine (Mavenclad) is an oral medication approved for certain forms of MS, known for its selective and sustained reduction of lymphocytes. Understanding its specific impact on different immune cell populations, such as B-cells, plasma cells, T cells, and regulatory T cells (Tregs), is crucial for elucidating its mechanism of action and optimizing treatment strategies. B-cells, in particular, are increasingly recognized for their role in MS pathogenesis.
Trial design
This completed study, titled "Oral Cladribine B-cell Study," enrolled 10 participants with Multiple Sclerosis. The trial's objective was to investigate the impact of cladribine on peripheral and intrathecal B-cell, plasma cells, T cells, and Tregs. The intervention studied was Cladribine (Mavenclad, Merck Serono Ltd).
Key results
Key measurements from the study provide insights into cladribine's effects on various immune markers:
- The percent change in class-switched memory B cells from baseline to Week 96 showed a median reduction of -62.8%.
- Changes in CSF of κ Free Light Chain (KFLC) from baseline to Week 48 and Week 96 were observed, with mean values of 164.5 (Standard Deviation 227.1), 71.3 (Standard Deviation 82.74), and 64.4 (Standard Deviation 67.34) kFLCIndex.
- Regarding changes in CSF Oligoclonal Band (OCB) positivity from baseline to Week 48 and Week 96, participant counts were 4, 2, 3, and 1.
- Changes in CSF of λ Free Light Chain (LFLC) Index from baseline to Week 48 and Week 96 showed mean values of 31.94 (Standard Deviation 25.47), 29.48 (Standard Deviation 25.14), and 27.18 (Standard Deviation 25.86) LFLCIndex.
- The change in CSF CXCL-13 levels from baseline to Week 96 was a mean of 88.6 (Standard Deviation 68.4) pg/ml.
What this means
The observed median 62.8% reduction in class-switched memory B cells suggests a significant impact of oral cladribine on these immune cell populations, which are implicated in the pathology of Multiple Sclerosis. The changes in cerebrospinal fluid (CSF) markers, including κ and λ free light chain indices, oligoclonal band positivity, and CXCL-13 levels, provide further evidence of cladribine's influence on intrathecal immune activity. These findings contribute to a deeper understanding of how cladribine modulates the immune system in MS patients, potentially informing future treatment strategies and patient selection.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for the study NCT06415864, titled "Oral Cladribine B-cell Study," were posted on 2026-02-04 on clinicaltrials.gov.