Cladribine Tablets: Collaborative Study to Evaluate Impact On Central Nervous System Biomarkers in Multiple Sclerosis (CLOCK-MS)

July 26, 2026 updated by: Gregory Wu

Cladribine Tablets: Collaborative Study to Evaluate the Impact On Central Nervous System Biomarkers in Multiple Sclerosis

The purpose of this study is to better understand the mechanism of action (MoA) of cladribine tablets by exploring the effect on central nervous system (CNS) and blood biomarkers relevant in the relapsing forms of multiple sclerosis (RMS; to include relapsing-remitting MS [RRMS] or active secondary progressive MS).

Study Overview

Status

Completed

Intervention / Treatment

Detailed Description

This is an open label, randomized, multicenter collaborative research Phase 4 biomarker study, designed to generate hypotheses to better understand the MoA of cladribine tablets in RMS (to include RRMS or active secondary progressive MS). The study is designed to generate hypotheses regarding the impact and relevance of cladribine tablet activity in the CNS by assessing the cerebrospinal (CSF) levels of lymphocyte subsets, other immune cells, neuronal injury markers and soluble immunological markers in study participants with RMS before and during treatment with cladribine tablets, and the association of these CSF markers with corresponding blood markers and with clinical outcomes.

Study Type

Interventional

Enrollment (Actual)

47

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Missouri
      • St Louis, Missouri, United States, 63110
        • Washington University School of Medicine
    • Oklahoma
      • Oklahoma City, Oklahoma, United States, 73104
        • Oklahoma Medical Research Foundation
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104
        • University of Pennsylvania
    • Texas
      • Dallas, Texas, United States, 75390
        • University of Texas Southwestern Medical Center
    • Wisconsin
      • Milwaukee, Wisconsin, United States, 53226
        • Medical College of Wisconsin

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Have a relapsing form of multiple sclerosis (RMS; to include RRMS or active secondary progressive MS)
  2. Are willing and able to receive at least 2 lumbar punctures
  3. Have an EDSS of 0 to ≤ 5.5 during the screening period
  4. Had at least 1 relapse or 1 gadolinium-enhancing or 1 new or enlarged T2 lesion in the last 12 months
  5. Have absolute lymphocyte count (ALC) within normal range of the local laboratory or assessed as normal by the investigator within the 3 week screening period and meet all other eligibility criteria for cladribine tablet treatment
  6. Capable of giving signed informed consent

Exclusion Criteria:

  1. Have any contraindication for lumbar puncture
  2. Have current malignancy
  3. Are infected with human immunodeficiency virus (HIV)
  4. Have active chronic infections (e.g. hepatitis or tuberculosis)
  5. Have signs or symptoms suggestive of progressive multifocal leukoencephalopathy (PML) in MRI
  6. Have history of hypersensitivity to cladribine or any of the excipients listed in the cladribine tablets US Prescribing Information
  7. Allergy or hypersensitivity to gadolinium and/or any other contraindication to perform a MRI
  8. Have any other comorbid conditions that preclude participation
  9. Have been previously treated with cladribine
  10. Have previously been treated with ocrelizumab, alemtuzumab, rituximab, or daclizumab
  11. Have received treatment with natalizumab during the last 6 months
  12. Are currently receiving immunosuppressive or myelosuppressive therapy, e.g., methotrexate, cyclophosphamide, cyclosporine or azathioprine, or chronic treatment with systemic corticosteroids
  13. Have received treatment with immunosuppressive or myelosuppressive therapy during the last 6 months
  14. Have received chronic treatment with systemic corticosteroids during the last 4 weeks
  15. Have moderate or severe hepatic impairment (Child-Pugh score >6)
  16. Have moderate or severe renal impairment (creatinine clearance <60 mL per minute)
  17. Are pregnant or unwilling or unable to use effective contraception during cladribine tablets dosing and for 6 months after the last dose in each treatment course
  18. Are intending to breastfeed on a cladribine tablet treatment day and/or during the 10 days after the last cladribine tablet dose.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Group 1: LP at Baseline and Week 5
Group 1: LP at Baseline and end of Week 5. Week 5 is the optimal time point for assessing cladribine concentrations in CSF
All participants will receive cladribine 10 mg tablets at a cumulative dosage of 3.5 mg/kg divided into 2 treatment courses as per the United States Prescribing Information (USPI) (1.75 mg/kg per treatment course; Year 1 and Year 2 treatment). Patients will be randomized 1:2:2:1 to receive a total of 2 Lumbar Punctures at specific time points during the treatment cycle.
Other: Group 3: LP at Baseline and End of Year 1
Group 3: LP at Baseline and end of Year 1. To assess if cladribine effects on CSF markers are maintained at the end of the first treatment cycle
All participants will receive cladribine 10 mg tablets at a cumulative dosage of 3.5 mg/kg divided into 2 treatment courses as per the United States Prescribing Information (USPI) (1.75 mg/kg per treatment course; Year 1 and Year 2 treatment). Patients will be randomized 1:2:2:1 to receive a total of 2 Lumbar Punctures at specific time points during the treatment cycle.
Other: Group 4: LP at Baseline and End of Year 2
Group 4: LP at Baseline and end of Year 2. To assess if cladribine effects on CSF markers are maintained at the end of the last treatment cycle
All participants will receive cladribine 10 mg tablets at a cumulative dosage of 3.5 mg/kg divided into 2 treatment courses as per the United States Prescribing Information (USPI) (1.75 mg/kg per treatment course; Year 1 and Year 2 treatment). Patients will be randomized 1:2:2:1 to receive a total of 2 Lumbar Punctures at specific time points during the treatment cycle.
Other: Group 2: LP at Baseline and Week 10
Group 2: LP at Baseline and end of Week 10. Week 10 is the hypothesized "nadir" time for lymphocyte and monocyte levels in CSF
All participants will receive cladribine 10 mg tablets at a cumulative dosage of 3.5 mg/kg divided into 2 treatment courses as per the United States Prescribing Information (USPI) (1.75 mg/kg per treatment course; Year 1 and Year 2 treatment). Patients will be randomized 1:2:2:1 to receive a total of 2 Lumbar Punctures at specific time points during the treatment cycle.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in CD3+ T Cells % From Baseline to Week 5
Time Frame: Baseline to Week 5 (5 weeks after first cladribine dose)
Change in CSF level of CD3+ T lymphocytes from Baseline to second LP at Week 5, using quality-controlled flow cytometry and assays. Within-group differences from baseline to Week 5 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD3+ T cell percentage and a negative number indicates decrease in CD3+ T cell percentage.
Baseline to Week 5 (5 weeks after first cladribine dose)
Change in CD3+ T Cells % From Baseline to Week 10
Time Frame: Baseline to Week 10 (10 weeks after first cladribine dose)
Change in CSF level of CD3+ T lymphocytes from Baseline to second LP at Week 10, using quality-controlled flow cytometry and assays. Within-group differences from Baseline to Week 10 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD3+ T cell percentage and a negative number indicates decrease in CD3+ T cell percentage.
Baseline to Week 10 (10 weeks after first cladribine dose)
Change in CD3+ T Cells % From Baseline to Year 1
Time Frame: Baseline to Year 1 (45 weeks after first cladribine dose)
Change in CSF level of CD3+ T lymphocytes from Baseline to second LP at Year 1, using quality-controlled flow cytometry and assays. Within-group differences from Baseline to Year 1 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD3+ T cell percentage and a negative number indicates decrease in CD3+ T cell percentage.
Baseline to Year 1 (45 weeks after first cladribine dose)
Change in CD3+ T Cells % From Baseline to Year 2
Time Frame: Baseline to Year 2 (45 weeks after last cladribine dose)
Change in CSF level of CD3+ T lymphocytes from Baseline to second LP at Year 2, using quality-controlled flow cytometry and assays. Within-group differences from Baseline to Year 2 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD3+ T cell percentage and a negative number indicates decrease in CD3+ T cell percentage.
Baseline to Year 2 (45 weeks after last cladribine dose)
Change in CD3+ T Cells Absolute Numbers (Cells/mL) From Baseline to Week 5
Time Frame: Baseline to Week 5
Change in CSF level of CD3+ T cells absolute numbers from Baseline to second LP at Week 5, using quality-controlled flow cytometry and assays. Within-group differences from baseline to Week 5 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD3+ T cells absolute numbers and a negative number indicates decrease in CD3+ T cells absolute numbers.
Baseline to Week 5
Change in CD3+ T Cells Absolute Numbers (Cells/mL) From Baseline to Week 10
Time Frame: Baseline to Week 10 (10 weeks after first cladribine dose)
Change in CSF level of CD3+ T cells absolute numbers from Baseline to second LP at Week 10, using quality-controlled flow cytometry and assays. Within-group differences from Baseline to Week 10 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD3+ T cells absolute numbers and a negative number indicates decrease in CD3+ T cells absolute numbers.
Baseline to Week 10 (10 weeks after first cladribine dose)
Change in CD3+ T Cells Absolute Numbers (Cells/mL) From Baseline to Year 1
Time Frame: Baseline to Year 1 (45 weeks after first cladribine dose)
Change in CSF level of CD3+ T cells absolute numbers from Baseline to second LP at Year 1, using quality-controlled flow cytometry and assays. Within-group differences from Baseline to Year 1 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD3+ T cells absolute numbers and a negative number indicates decrease in CD3+ T cells absolute numbers.
Baseline to Year 1 (45 weeks after first cladribine dose)
Change in CD3+ T Cells Absolute Numbers (Cells/mL) From Baseline to Year 2
Time Frame: Baseline to Year 2 (45 weeks after last cladribine dose)
Change in CSF level of CD3+ T cells absolute numbers from Baseline to second LP at Year 2, using quality-controlled flow cytometry and assays. Within-group differences from Baseline to Year 2 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD3+ T cells absolute numbers and a negative number indicates decrease in CD3+ T cells absolute numbers.
Baseline to Year 2 (45 weeks after last cladribine dose)
Change in CD19+ B Cells % From Baseline to Week 5
Time Frame: Baseline to Week 5 (5 weeks after first cladribine dose)
Change in CSF level of CD19+ B lymphocytes from Baseline to second LP at Week 5, using quality-controlled flow cytometry and assays. Within-group differences from Baseline to Week 5 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD19+ B cell percentage and a negative number indicates decrease in CD19+ B cell percentage.
Baseline to Week 5 (5 weeks after first cladribine dose)
Change in CD19+ B Cells % From Baseline to Week 10
Time Frame: Baseline to Week 10 (10 weeks after first cladribine dose)
Change in CSF level of CD19+ B lymphocytes from Baseline to second LP at Week 10, using quality-controlled flow cytometry and assays. Within-group differences from Baseline to Week 10 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD19+ B cell percentage and a negative number indicates decrease in CD19+ B cell percentage.
Baseline to Week 10 (10 weeks after first cladribine dose)
Change in CD19+ B Cells % From Baseline to Year 1
Time Frame: Baseline to Year 1 (45 weeks after first cladribine dose)
Change in CSF level of CD19+ B lymphocytes from Baseline to second LP at Year 1, using quality-controlled flow cytometry and assays. Within-group differences from Baseline to Year 1 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD19+ B cell percentage and a negative number indicates decrease in CD19+ B cell percentage.
Baseline to Year 1 (45 weeks after first cladribine dose)
Change in CD19+ B Cells % From Baseline to Year 2
Time Frame: Baseline to Year 2 (45 weeks after last cladribine dose)
Change in CSF level of CD19+ B lymphocytes from Baseline to second LP at Year 2, using quality-controlled flow cytometry and assays. Within-group differences from Baseline to Year 2 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD19+ B cell percentage and a negative number indicates decrease in CD19+ B cell percentage.
Baseline to Year 2 (45 weeks after last cladribine dose)
Change in CD19+ B Cells Absolute Numbers (Cells/mL) From Baseline to Week 5
Time Frame: Baseline to Week 5 (5 weeks after first cladribine dose)
Change in CSF level of CD19+ B cells absolute numbers from Baseline to second LP at Week 5, using quality-controlled flow cytometry and assays. Within-group differences from Baseline to Week 5 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD19+ B cells absolute numbers and a negative number indicates decrease in CD19+ B cells absolute numbers.
Baseline to Week 5 (5 weeks after first cladribine dose)
Change in CD19+ B Cells Absolute Numbers (Cells/mL) From Baseline to Week 10
Time Frame: Baseline to Week 10 (10 weeks after first cladribine dose)
Change in CSF level of CD19+ B cells absolute numbers from Baseline to second LP at Week 10, using quality-controlled flow cytometry and assays. Within-group differences from Baseline to Week 10 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD19+ B cells absolute numbers and a negative number indicates decrease in CD19+ B cells absolute numbers.
Baseline to Week 10 (10 weeks after first cladribine dose)
Change in CD19+ B Cells Absolute Numbers (Cells/mL) From Baseline to Year 1
Time Frame: Baseline to Year 1 (45 weeks after first cladribine dose)
Change in CSF level of CD19+ B cells absolute numbers from Baseline to second LP at Year 1, using quality-controlled flow cytometry and assays. Within-group differences from Baseline to Year 1 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD19+ B cells absolute numbers and a negative number indicates decrease in CD19+ B cells absolute numbers.
Baseline to Year 1 (45 weeks after first cladribine dose)
Change in CD19+ B Cells Absolute Numbers (Cells/mL) From Baseline to Year 2
Time Frame: Baseline to Year 2 (45 weeks after last cladribine dose)
Change in CSF level of CD19+ B cells absolute numbers from Baseline to second LP at Year 2, using quality-controlled flow cytometry and assays. Within-group differences from Baseline to Year 2 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in CD19+ B cells absolute numbers and a negative number indicates decrease in CD19+ B cells absolute numbers.
Baseline to Year 2 (45 weeks after last cladribine dose)
Change in the Neurofilament Light Chain (NfL) Level From Baseline to Week 5
Time Frame: Baseline to Week 5 (5 weeks after first cladribine dose)
Change in CSF level NfL (measured in pg/mL) from baseline to week 5 using the highly sensitive Neurology 4-Plex D Advantage Plus (N4PD+) single molecule array (SIMOA) technology. A single batch of samples with duplicates were run at the conclusion of the study. Within-group differences from baseline to Week 5 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in NfL value and a negative number indicates decrease in NfL value.
Baseline to Week 5 (5 weeks after first cladribine dose)
Change in the Neurofilament Light Chain (NfL) Level From Baseline to Week 10
Time Frame: Baseline to Week 10 (10 weeks after first cladribine dose)
Change in CSF level NfL (measured in pg/mL) from baseline to Week 10 using the highly sensitive Neurology 4-Plex D Advantage Plus (N4PD+) single molecule array (SIMOA) technology. A single batch of samples with duplicates were run at the conclusion of the study. Within-group differences from baseline to Week 10 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in NfL value and a negative number indicates decrease in NfL value.
Baseline to Week 10 (10 weeks after first cladribine dose)
Change in the Neurofilament Light Chain (NfL) Level From Baseline to Year 1
Time Frame: Baseline to Year 1 (45 weeks after first cladribine dose)
Change in CSF level NfL (measured in pg/mL) from baseline to Year 1 using the highly sensitive Neurology 4-Plex D Advantage Plus (N4PD+) single molecule array (SIMOA) technology. A single batch of samples with duplicates were run at the conclusion of the study. Within-group differences from baseline to Year 1 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in NfL value and a negative number indicates decrease in NfL value.
Baseline to Year 1 (45 weeks after first cladribine dose)
Change in the Neurofilament Light Chain (NfL) Level From Baseline to Year 2
Time Frame: Baseline to Year 2 (45 weeks after last cladribine dose)
Change in CSF level NfL (measured in pg/mL) from baseline to year 2 using the highly sensitive Neurology 4-Plex D Advantage Plus (N4PD+) single molecule array (SIMOA) technology. A single batch of samples with duplicates were run at the conclusion of the study. Within-group differences from baseline to year 2 were analyzed using the Wilcoxon signed-rank test because outcome differences were non-normally distributed. Positive number indicates increase in NfL value and a negative number indicates decrease in NfL value.
Baseline to Year 2 (45 weeks after last cladribine dose)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Collaborators

Investigators

  • Principal Investigator: Gregory Wu, MD, PhD, Washington University School of Medicine

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 28, 2019

Primary Completion (Actual)

May 27, 2025

Study Completion (Actual)

May 27, 2025

Study Registration Dates

First Submitted

May 23, 2019

First Submitted That Met QC Criteria

May 23, 2019

First Posted (Actual)

May 24, 2019

Study Record Updates

Last Update Posted (Actual)

July 28, 2026

Last Update Submitted That Met QC Criteria

July 26, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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