INCREASE

Treatment tested

• D-aspartate
• Interferon beta-1a

  Interferon alpha/beta receptor agonist

• Methylprednisolone

  Glucocorticoid receptor agonist

Placebo or sham

• Placebo

Other measures (9)

Inclusion Criteria: * Participants with RR-MS, according to the revised McDonald Criteria (2010) * Participants with an expanded disability status scale (EDSS) score between 0 and 3 before screening visit and before relapse * Participants receiving treatment with IFN beta 1a 44 mcg three times a week for at least 6 months but for no more than 10 years before the screening visit * Female participants must be neither pregnant nor breastfeeding and must lack childbearing potential * Participants willing and able to comply with the protocol for the total duration of the study * Participants able to understand the purposes and the risks of the study * Participants have signed the appropriate written informed consent form, approved by the Independent Ethics Committee (IEC), prior to the performance of any study activities * For MS participants with relapse: * Deterioration of at least one step in a relevant Functional Systems Scale (FSS) or an increase in EDSS of 1 point or more compatible, according to physician's judgment, with the therapy prosecution * Relapse started within maximum 5 days before the inclusion in the study * MS participants without relapse with clinically stable RR-MS Exclusion Criteria: * Participants with diagnosis of primary progressive MS (PP-MS) * Participants have any disease other than MS that could better explain his/her signs and symptoms * Participants with any comorbidity with diseases that might alter synaptic plasticity (example Parkinson Disease, Alzheimer Disease, Stroke) * Participants receiving concomitant treatment with drugs that may alter synaptic plasticity (example, cannabinoids) * Participants with history or presence of any unstable medical condition (tumor or chronic infection or severe life threatening infection within the last 6 months) * Participants who have received any corticosteroids therapy within 3 months prior to the screening * Participants with any concomitant disease that may require chronic treatment with systemic corticosteroids or immunosuppressive agents during the course of the study * Participants who have received any immunosuppressive agents other to corticosteroids, as monotherapy or combination therapy within 3 months prior to the screening visit * Participants with history or currently active primary or secondary immunodeficiency * Participants with inadequate liver function, defined by alanine aminotransferase (ALT) > 3 * upper limit of normal (ULN), or alkaline phosphatase (AP) > 2 * ULN, or total bilirubin > 2 * ULN if associated with any elevation of ALT or AP * Participants with inadequate bone marrow reserve, defined as a white blood cell count less than 0.5 * lower limit of normal (LLN) * Participants with moderate to severe renal impairment * Participants unable to complete an magnetic resonance imaging (MRI) (contraindications for MRI include but are not restricted to weight >=140 kilogram (kg), pacemaker, cochlear implants, presence of foreign substances in the eye, intracranial vascular clips, surgery within 6 weeks of entry into the study, coronary stent implanted within 8 weeks prior to the time of the intended MRI, etc) * Participants with contraindication to gadolinium (Gd) can be enrolled into the study but cannot receive Gd contrast dyes during their MRI scans * Participants receiving supplements that, in the Investigator's opinion, may affect the evaluation of fatigue * Participants with any known contraindications or hypersensitivity to D-aspartate or any excipient * Participants with any other significant disease that in the Investigator's opinion would impede study assessments or endanger the participant * Female participants with positive pregnancy test at baseline or participants with active project of pregnancy during the study * Participants with legal incapacity or limited legal capacity * Participants have participated in any other investigational study within 8 weeks before the screening visit

The purpose of this study was to evaluate the improvement in spontaneous recovery from clinical deficits at the time of an acute relapse in RR-MS participants already receiving interferon (IFN) beta 1a with D-aspartate (versus placebo) as add-on therapy.