Oral Cladribine in Early Multiple Sclerosis (MS)

A randomized, double-blind, clinical trial to assess the safety and efficacy of two doses of oral cladribine versus placebo in participants who had a first clinical demyelinating event (clinically isolated syndrome). Participants in either the cladribine or placebo group may also enter treatment periods with open-label interferon-beta or open-label cladribine depending upon the disease status. The primary objective of this study is to evaluate the effect of two dosage regimens of oral cladribine versus placebo on the time to conversion to multiple sclerosis (MS) (from randomization) according to the Poser criteria in participants with first clinical demyelinating event at high risk of converting to MS.

This will be a randomized, double blind, three-arm, placebo-controlled, multi-center trial to evaluate the safety and efficacy of oral cladribine versus placebo in the treatment of participants who have sustained a first clinical demyelinating event within 75 days prior to the Screening. Participants must have a minimum of 2 clinically silent lesions on the Screening magnetic resonance imaging (MRI).

The study will include a pre-study evaluation period (Screening period: between 10 and 28 days prior to the start of treatment with blinded study medication (oral cladribine or placebo).

Depending upon the clinical course of their MS, participants will then proceed from the ITP to either the Maintenance Treatment Period (with open-label interferon-beta treatment) or LTFU period (with either open-label low-dose cladribine or no additional treatment (if no progression to MS has been noted after the initial treatment period). The single primary endpoint for the overall study, which will be determined during the ITP, is time to conversion to MS (from randomization), according to the Poser criteria.

For every participants, eligibility for study enrollment and entry into each of the study periods, and diagnosis of conversion to either McDonald MS or CDMS must be confirmed and approved by a Sponsor appointed study Adjudication Committee.

Eligibility Criteria:
Inclusion Criteria:

* Male or female between 18 and 55 years old, inclusive
* Weighed between 40 to 120 kilogram (kg), inclusive
* Participant has experienced a single, first clinical event suggestive of MS within 75 days prior to the Screening visit, (clock starts 24 hours after onset). The event must be a new neurological abnormality present for at least 24 hours, either mono- or polysymptomatic
* Participant has at least two clinically silent lesions on the T2-weighted MRI scan, at screening, with a size of at least 3 millimeter (mm), at least one of which is ovoid or periventricular or infratentorial on screening MRI
* Participant has EDSS 0 - 5.0 at Screening
* Participant has no medical history or evidence of latent tuberculosis infection (LTBI) or active tubercular disease, as evidenced by the Mantoux tuberculosis (TB) skin test or a comparable sensitive test according to local regulations/guidelines (if the Mantoux test is not available), and/or a chest X-ray
* Participant has normal hematological parameters at Screening, as defined by the central laboratory that performed all the assessments
* If female, she must:

  * be neither pregnant nor breast-feeding, nor attempting to conceive and
  * use a highly effective method of contraception throughout the entire duration of the study and for 90 days following completion of the last dose of study medication. A highly effective method of contraception is defined as those which result in a low failure rate (that is less than 1 percent per year) when used consistently and correctly such as implants, injectables, combined oral contraceptives, some intrauterine devices, sexual abstinence or vasectomized partner, or
  * be post-menopausal or surgically sterilized (Note: for Danish sites only, participants should use a hormonal contraceptive or intrauterine device for the duration of the trial)
* Male participants must be willing to use contraception to avoid impregnating partners throughout the study, and for 90 days following the last dose of study medication
* Be willing and able to comply with study procedures for the duration of the study
* Participant has to provide written informed consent voluntarily, including, for United states of America (USA), participant authorization under Health Insurance Portability and Accountability Act (HIPAA), prior to any study-related procedure that is not part of normal medical care
* Participant has refused any treatment already available for clinically isolated syndrome (CIS) such as interferons or glatiramer acetate, at the time of entry into the Initial Treatment Period of this study

Exclusion Criteria:

* Participant has a diagnosis of MS (per McDonald criteria, 2005)
* Participant has any other disease that could better explain the participant's signs and symptoms
* Participant has complete transverse myelitis or bilateral optic neuritis
* Participant using or has used any other approved MS disease modifying drug (DMD)
* Participant has used any investigational drug or undergone an experimental procedure within 12 weeks prior to Study day 1
* Participant received oral or systemic corticosteroids or adrenocorticotropic hormone (ACTH) within 30 days prior to screening MRI. The MRI had to be performed 30 days after the oral or systemic corticosteroids or ACTH treatment. In case this interfered with MRI timing the screening period could be extended accordingly.
* Participant has abnormal total bilirubin, or aspartate aminotransferase (AST) or alanine aminotransferase (ALT) or alkaline phosphatase greater than 2.5 times the upper limit of normal
* Participant suffered from current autoimmune disease other than MS
* Participant suffered from psychiatric illness (including history of, or concurrent, severe depressive disorders and/or suicidal ideation) that in the opinion of the investigator creates undue risk to the participant or could affect compliance with the study protocol
* Participant suffered from major medical illness such as cardiac (for example angina, congestive heart failure or arrhythmia), endocrinologic, hepatic, immunologic, metabolic, renal, pulmonary, gastrointestinal, dermatologic, or other major disease that would preclude the administration of oral cladribine
* Participant has a history of seizures not adequately controlled by medications
* Participant has a known allergy to cladribine, interferon-beta, the excipient(s) of the study medications, or to gadolinium- diethylenetriamine penta-acetic acid (DTPA)
* Participant has any renal condition that would preclude the administration of gadolinium (for example acute or chronic severe renal insufficiency (glomerular filtration rate \[GFR\] less than 30 milliliter per minute per 1.73 square meter \[mL/min/1.73 m\^2\])
* Participant has a history of chronic or clinically significant hematological abnormalities
* Participant has a history of active or chronic infectious disease or any disease that compromises immune function (for example human immunodeficiency virus positive \[HIV+\], human T-lymphotrophic virus \[HTLV-1\], Lyme disease, latent tuberculosis infection \[LTBI\] or TB, insulin-dependent diabetes).
* Participant has previously been screened in this study (signed an informed consent) and then withdrawn
* Participant has received any immunomodulatory or immunosuppressive therapy) at any time prior to Study Day 1, including, but not limited to, the following products: any interferon, glatiramer acetate (Copolymer I), cyclophosphamide, cyclosporine, methotrexate, linomide, azathioprine, mitoxantrone, teriflunomide, laquinimod, cladribine, total lymphoid irradiation, anti-lymphocyte monoclonal antibody treatment (for example natalizumab, alemtuzumab/Campath, anti-cluster of differentiation 4 \[CD4\]), intravenous immunoglobulin G (IVIG), cytokines or anti-cytokine therapy
* Participant has received experimental MS treatment
* Participant has a history of alcohol or drug abuse
* Participant has intolerance or any contraindication to both paracetamol (acetaminophen) and ibuprofen
* Participant has inability to administer subcutaneous injections either by self or by caregiver
* Participant has prior or current malignancy (with the exception of in situ basal or squamous cell skin cancer surgically removed without recurrence for at least five years)
* Participant has a positive stool hemoccult test at Screening