The purpose of the study is to assess the influence of pantoprazole on the pharmacokinetic profile of cladribine, especially in terms of extent of absorption of cladribine since pH-modifying drug may potentially affect the stability of cladribine and thereby its bioavailability

Inclusion Criteria:

• Subjects with a body mass index less than or equal to (<=) 28 and have a body weight greater than (>) 60 kilogram (kg) and less than (<) 120 kg, at screening
• Able to understand informed consent and had given written, informed consent
• Had a diagnosis of clinically stable and definite multiple sclerosis (MS) by either McDonald or Poser criteria
• Expanded disability status scale (EDSS) score not to exceed 5.0
• Male or non-pregnant, non-breast feeding women aged 18 to 65 years, inclusive at the time that informed consent was obtained
• Female subjects lacking childbearing potential defined as post-menopausal for at least two years, surgically or medically sterile or sexually inactive; or willing to avoid pregnancy by using an adequate method of birth control for 28 days prior to, during and up to 90 days after the last administration of trial medication

Other protocol defined inclusion criteria could apply.

Exclusion Criteria:

• Subjects presenting a severe or unstable disorder: poorly controlled diabetes or arterial hypertension, severe cardiac insufficiency, unstable ischemic heart disease, a significant pre-existing hematological disease, or any medical condition, which in the opinion of the investigator, would constitute a risk or a contraindication for the participation of the subject to the study or that could interfere with the study objectives, conduct or evaluation
• Subjects who were on MS treatment; and subjects who were on a non-stable symptomatic MS treatment (stable dose was defined as 3 weeks or longer prior to first study dose)
• Clinically significant abnormal laboratory test results or electrocardiogram findings that in the opinion of the investigator could increase the safety risk to the subject
• Positive results from serology examination for Hepatitis B surface antigen (HbsAg) not due to vaccination, hepatitis B core antibody (HbcAb), Hepatitis C virus antibody (anti-HCV) or Human Immunodeficiency antibody (anti-HIV)
• Signs and symptoms of Transmissible Spongiform Encephalopathy at screening, or family members who suffered from such
• Presence of chronic or recurrent infection or any acute infection within the last 2 weeks before first dosing in each study period
• Presence of gastrointestinal disease that, in the opinion of the investigator, could affect the pharmacokinetic outcome of the study
• Consumption of any concomitant medication that could directly influence gastric acidity (example: use of antacids, histamine receptor (H2) antagonists or other proton pump inhibitor) taken within 7 days of study day 1 and throughout the study period
• Intake of alcoholic beverages, caffeine and caffeine containing beverages, grapefruit, oranges, cranberries and juices of these three fruits or smoking in the 48 hours prior to first dose and 48 hours post dose (cladribine)
• Exposure to any investigational drug or the use of any investigational device in the 12 weeks prior to first dose
• Intake of any medications that could directly influence gastrointestinal motility and absorption of cladribine (example, use of H2-antagonists, proton pump inhibitors) 7 days prior to cladribine administration
• Any immunomodulatory therapy (including but not limited to glatiramer acetate, interferons, or natalizumab) and treatment with oral or systemic corticosteroids or adrenocorticotropic hormone within 28 days of first dosing
• Any cytokine or anti-cytokine therapy, IV immunoglobulin administration or plasmapheresis was prohibited in the 3 months prior to first dosing
• Current history or presence of drug or alcohol abuse, confirmed by positive test results for drugs of abuse and/or alcohol or had a history of drug or alcohol abuse. Alcohol abuse was defined as: an average daily intake of more than 3 units or a weekly intake of more than 21 for males and 14 units for females where 1 unit equals 8-10 gram alcohol (1 unit equals 340 milliliter [mL] of beer, 115 mL of wine or 43 mL of spirits)
• History or presence of hypertension or other significant cardiovascular abnormality, history of heart or kidney disease
• Current diagnosis or personal history of cancer
• Smoke 10 cigarettes or more per day or equivalent
• Loss or donation of more than 400 mL of blood in the 12 weeks prior to first dose.
• Definite or suspected personal history or family history of adverse drug reaction or hypersensitivity to drugs with a similar chemical structure to cladribine or pantoprazole or with known hypersensitivity to cladribine or pantoprazole excipients
• Presence or history of any serious allergy (requiring hospitalization or prolonged systemic treatment)
• Pregnant or nursing women. Treatment of pregnant and nursing women with cladribine in this study was prohibited
• Signs or symptoms of neurological disease other than MS that could explain the symptoms of the subject

Baseline analysis population included all randomized subjects.

Up to 1 year