Cladribine

Parent company: EMD Serono, Inc.

This drug is given orally for four to five consecutive days, ranging from once every 28 days to twice yearly, depending on the study regimen.

Based on studies of injectable cladribine showing a reduction in gadolinium-enhancing lesions that averaged 90 percent and a marked reduction in relapse rate, the orally administered form was designated by the FDA as a Fast Track product for relapsing forms of MS, for potentially quick approval. If found to be both safe and effective, it may be approved in 2009.

This drug interferes with the proliferation of a specific class of T cells in the immune system.

The injectable form is generally well tolerated; side effects include fatigue, headache, and infections.

The ongoing two-year, Phase III CLARITY extension study will assess the safety and efficacy of oral cladribine in RRMS, as well as its effect on progression of disability. All participants completed an earlier CLARITY trial that tested two doses of oral cladribine.

The ONWARD Phase II study (of 260 individuals who have experienced at least one relapse while taking Rebif) combines oral cladribine with the new formulation of Rebif, to determine whether the combination is more effective than Rebif alone.