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Updated May 2026 · ClinicalTrials.gov

RECRUITINGPhase 2 / Phase 3INTERVENTIONAL

Cladribine vs Placebo for Non-active Progressive Multiple Sclerosis (CLASP-MS).

Safety and Efficacy of Subcutaneous Cladribine for Nonrelapsing, Secondary Progressive Multiple Sclerosis (CLASP-MS): a Randomized, Placebo-controlled, Double-blind, Phase 2 Study.

Cladribine vs Placebo for Non-active Progressive Multiple Sclerosis (CLASP-MS). (NCT05961644) is a Phase 2 / Phase 3 interventional studying Multiple Sclerosis, Secondary Progressive and Multiple Sclerosis, sponsored by Institute of Psychiatry and Neurology, Warsaw. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

Important: This information is not medical advice. Talk to your doctor about whether a clinical trial is right for you.

About This Trial

The purpose of the study is to evaluate the efficacy and safety of subcutaneously administered cladribine versus placebo to stop inflammation and treat disease progression of non-active secondary progressive multiple sclerosis. Multiple sclerosis is an inflammatory disease of the central nervous system. In most patients, it starts with a relapsing course (RMS) which is caused by acute inflammatory lesions in the brain and spinal cord. RMS transforms at later stages into progressive disease (secondary progressive MS). Currently approved disease-modifying treatments are effective in reducing clinical relapses and brain and spinal lesions visible in MR, but they perform poorly in preventing disease progression and overall disability accumulation. The growing evidence shows that disease progression partially depends on chronic inflammation present in the CNS. Drugs, which may cross the blood-brain barrier and reach inflammatory cells residing in the CNS might be effective in this stage of the disease. Cladribine is one of the DMT approved for RMS. It is a synthetic purine analog with selective lymphocyte toxicity, which enter the CNS and is found in cerebrospinal fluid. In patients treated with cladribine, the oligoclonal bands tend to disappear proving that neuroinflammation is diminished. The participants of this clinical trial with the later non-active stage of MS are enrolled to be treated with cladribine subcutaneously or a non-active comparator (placebo) for 6 months and followed for the next 2 years, with an MRI scan and clinical evaluation every 6 months. The main questions it aims to answer are if in the non-active stage of MS cladribine is potent to lessen brain volume loss and if it is potent to attenuate inflammation in the CNS.

What Stage of Research Is This?

Phase 2 trials evaluate whether a treatment actually works against Multiple Sclerosis, Secondary Progressive and continue monitoring side effects. Phase 2 enrolls larger groups (typically 100–300 patients) and produces the first real efficacy signal. A successful Phase 2 readout is what unlocks the much larger Phase 3 confirmatory trials needed for FDA approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

Target enrollment of 188 participants puts this in the typical range for a Phase 2-style efficacy study or a moderate Phase 3 trial in a focused Multiple Sclerosis, Secondary Progressive subpopulation. At this scale, the study has enough statistical power to detect a clear treatment effect but is not the largest cohort in the field.

Who May Be Eligible (Plain English)

Who May Qualify: - Written willing to sign a consent form - Diagnosis of relapse-onset, secondary progressive multiple sclerosis based on the 2017 McDonald criteria - Progression of disability over 24 months defined as an increase in the EDSS score of 1 or more for patients with EDSS ≤ 5.5 or of 0.5 or more for patients with EDSS \> 5.5 - Lack of relapses over last 12 months - EDSS of 3.5 - 7.5 inclusive - Age of 30 - 65 years inclusive - Duration of MS of 10 years or longer - Pre-menopausal women must refrain from heterosexual intercourse or use a contraception method with a failure rate of \< 1% from enrolment up to 6 months after the last dose of the investigational medicinal product - Men must refrain from heterosexual intercourse from enrolment up to 6 months after the last dose of the investigational medicinal product or use a barrier method of contraception, with their female partners using a contraception method with a failure rate of \<1% - Able to fulfill all protocol requirements as judged by the investigator Who Should NOT Join This Trial: - Lack of written willing to sign a consent form - Previous cladribine treatment - Hypersensitivity to the investigational medicinal product - Eligible and willing to use interferon beta, siponimod, or mitoxantrone - Unable to undergo magnetic resonance imaging - Pregnancy or breastfeeding - Does not agree to use contraception methods defined above - Diseases of the nervous system, such as tumors, stroke, traumatic injury, encephalomyelitis, B12 deficiency, or demyelinating diseases other than multiple sclerosis - Major comorbidities, such as cancer, liver failure, kidney failure, heart failure (NYHA II-III), or any other disease that may jeopardize patient safety or make it impossible for the patient to fulfill protocol requirements - Relapse within last 12 months - Chronic treatment with corticosteroids or immunosuppressants (eg, azathioprine, methotrexate, cyclosporine) within last 6 months ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language
Inclusion Criteria: * Written informed consent * Diagnosis of relapse-onset, secondary progressive multiple sclerosis based on the 2017 McDonald criteria * Progression of disability over 24 months defined as an increase in the EDSS score of 1 or more for patients with EDSS ≤ 5.5 or of 0.5 or more for patients with EDSS \> 5.5 * Lack of relapses over last 12 months * EDSS of 3.5 - 7.5 inclusive * Age of 30 - 65 years inclusive * Duration of MS of 10 years or longer * Pre-menopausal women must refrain from heterosexual intercourse or use a contraception method with a failure rate of \< 1% from enrolment up to 6 months after the last dose of the investigational medicinal product * Men must refrain from heterosexual intercourse from enrolment up to 6 months after the last dose of the investigational medicinal product or use a barrier method of contraception, with their female partners using a contraception method with a failure rate of \<1% * Able to fulfill all protocol requirements as judged by the investigator Exclusion Criteria: * Lack of written informed consent * Previous cladribine treatment * Hypersensitivity to the investigational medicinal product * Eligible and willing to use interferon beta, siponimod, or mitoxantrone * Unable to undergo magnetic resonance imaging * Pregnancy or breastfeeding * Does not agree to use contraception methods defined above * Diseases of the nervous system, such as tumors, stroke, traumatic injury, encephalomyelitis, B12 deficiency, or demyelinating diseases other than multiple sclerosis * Major comorbidities, such as cancer, liver failure, kidney failure, heart failure (NYHA II-III), or any other disease that may jeopardize patient safety or make it impossible for the patient to fulfill protocol requirements * Relapse within last 12 months * Chronic treatment with corticosteroids or immunosuppressants (eg, azathioprine, methotrexate, cyclosporine) within last 6 months * Disease-modifying treatments for multiple sclerosis (no washout is required for interferons beta, glatiramer acetate, and dimethyl fumarate; washout of \> 6 months for teriflunomide, fingolimod, and natalizumab \[an accelerate elimination procedure may be used for teriflunomide instead\]; washout of \> 12 months for ocrelizumab, mitoxantrone, and alemtuzumab) * Relapsing-remitting multiple sclerosis * Primary progressive multiple sclerosis * Hepatitis B or hepatitis C, including detectable HbsA, anti-HBc, or anti-HCV antibodies in serum * HIV infection, including a positive screening test (anti-HIV 1/2, protein 24) * Active or latent tuberculosis, including a positive result of the QuantiFERON TB Gold test during screening or within 3 months (an inconclusive test must be repeated; two inconclusive tests are taken as a positive result) * Other infection that may be worsened by treatment with cladribine * Lymphopenia (\< 1000/μl), neutrocytopenia (\< 1500/μl), or thrombocytopenia * Alanine aminotransferase or aspartate aminotransferase \> 2 x ULN (can be repeated when 1.5-3x ULN); Total bilirubin \> 1.5 x ULN (can be repeated when 1.5-3 x ULN); Hemoglobin \> 9.5 g/dL (can be repeated when 9-9.4 g/dL) * Lack of vaccination against COVID-19 - the time from the last dose of a full vaccination regimen is shorter than 6 weeks * Any vaccination within last 6 weeks * Lack of cancer screening or suspicion of cancer or necessity to carry out additional studies after the following examinations done at screening: chest X-ray in all participants; mammography or breast ultrasound in women; cervical smear in women; prostate-specific antigen in men * Patient does not have detectable antibodies against Varicella zoster virus in serum or a proof of two-dose vaccination against this virus (last dose at least 6 months before enrolment) * Use of oral or parenteral anticoagulants or antiplatelets other than acetylsalicylic acid

Treatments Being Tested

DRUG

Cladribine Subcutaneous Injection

Cladribine subcutaneous injection, 10 mg daily, for 2-3 consecutive days (depending on individual dose)

DRUG

0.9% Chloride Injection Sodium

0.9% sodium chloride injected subcutaneously, 10 ml daily, for 2-3 consecutive days

Locations (1)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

Institute of Psychiatry and Neurology
Warsaw, Masovian Voivodeship, Poland

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT05961644), the sponsor (Institute of Psychiatry and Neurology, Warsaw), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT05961644 clinical trial studying?

The purpose of the study is to evaluate the efficacy and safety of subcutaneously administered cladribine versus placebo to stop inflammation and treat disease progression of non-active secondary progressive multiple sclerosis. Multiple sclerosis is an inflammatory disease of the central nervous system. In most patients, it starts with a relapsing course (RMS) which is caused by acute inflammatory lesions in the brain and spinal cord. RMS transforms at later stages into progressive disease (secondary progressive MS). Currently approved disease-modifying treatments are effective in reducing cl… The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT05961644?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT05961644?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT05961644. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT05961644. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.