Inclusion Criteria:

1. Signed informed consent
2. Have diagnosis of RMS, including RRMS and aSPMS, and satisfy the approved indication for cladribine tablets as per United States Prescribing Information (USPI)
3. Have time since diagnosis of RMS of at least 12 months
4. In the opinion of the investigator, experienced suboptimal response (lack of effectiveness, intolerability, poor adherence) to oral or infusion DMD treatment other than cladribine tablets
5. Had received their last previous oral DMD for at least 1 month or at least 1 dose of their last previous infusion DMD
6. Have decided to initiate treatment with cladribine tablets during routine clinical care
7. Meet criteria as per the approved USPI
8. Have access to a valid e-mail address

Exclusion Criteria:

1. Have been previously treated with cladribine in any dosing form (intravenous, subcutaneous, or oral)
2. Transitioning from previous oral DMD solely for administrative reasons such as relocation
3. Have comorbid conditions that preclude participation
4. Have any clinical condition or medical history noted as contraindication on USPI
5. Are currently participating in an interventional clinical trial
6. Pregnant or breastfeeding women, women who plan to become pregnant or men whose partner plans to become pregnant during study the cladribine treatment period