A Phase 2 Study of Cladribine Add-on to Interferon-beta (IFN-beta) Therapy in Multiple Sclerosis (MS) Subjects With Active Disease (ONWARD)

The goal of this study was to evaluate the safety, tolerability and effectiveness of oral cladribine when taken in combination with Interferon-beta (IFN-beta) therapy for the treatment of multiple sclerosis (MS). This study randomized around 200 participants from approximately 50 sites located world-wide, who have experienced at least one relapse while taking IFN-beta therapy within 48 weeks prior to Screening, irrespective of disability progression. Secondary progressive multiple sclerosis (SPMS) participants, who were still experiencing relapses, and participants who have received disease modifying drugs (DMDs), other than IFN-beta therapy, during their MS treatment history, but were currently on IFN-beta therapy and have experienced active MS symptoms (at least 1 relapse) during the 48 weeks prior to Screening, were enrolled. Participants were randomized in a 2:1 fashion to receive up to 4 cycles of oral cladribine or matching placebo in combination with IFN-beta therapy. Participants who completed the double-blind portion of the study were invited to participate in an open-label extension phase of matching study design.