The study will examine the safety, tolerability and effectiveness of oral cladribine combined with a new formulation of Rebif in multiple sclerosis patients with active disease despite treatment with Rebif. The primary efficacy endpoint is the mean change in the number of new T1 gadolinium-enhanced lesions per subject per magnetic resonance imaging (MRI) scan from baseline to 96 weeks.
Oral cladribine is currently also evaluated as a monotherapy in a phase III trial for first-line treatment of relapsing forms of multiple sclerosis. The new formulation of Rebif is under review by the European Medicines Agency, the FDA and other healthcare authorities.
“The different mechanism of action and the oral intermittent administration of oral cladribine make it a potentially useful add-on therapy to Rebif at a critical time of disease progression,” said Bruno Musch, Merck Serono's head of Neurology Clinical Development.
If approved, oral cladribine would become the first oral therapy for first-line treatment of multiple sclerosis.