MERCK SERONO LAUNCHES STUDY OF ADD-ON MS TREATMENT

Merck Serono has begun the ONWARD Phase II study. The trial study will evaluate the safety, tolerability and efficacy of two dose regimens of the company's proprietary oral formulation of cladribine when added to the new formulation of Rebif (interferon beta-1a) in multiple sclerosis (MS) patients with active disease despite treatment with Rebif. Oral cladribine is also being evaluated as a monotherapy in a fully enrolled Phase III pivotal trial for first-line treatment of relapsing forms of MS. The new formulation of Rebif is under regulatory review by the European Medicines Agency, the FDA and other authorities.

The ONWARD study is a two-year, randomized, double-blind, placebo-controlled, international trial. The trial will be conducted in 40 sites in the U.S. and in Europe. It will involve 260 MS patients who have experienced at least one relapse while taking Rebif during the year prior to study enrollment. Study participants will be randomized in one of the three arms of the study to receive one of two different dose regimens of oral cladribine or matching placebo tablets, in addition to the new formulation of Rebif at a dosage of 44 micrograms subcutaneous three times a week. In the study, oral cladribine is given in two or four treatment cycles in the first year, with each cycle consisting of daily administration for four or five consecutive days, which means study patients will take oral cladribine therapy for only eight to 20 days during that year. In the second year, two treatment cycles are administered in all dose regimens.

The primary efficacy endpoint is the mean change in the number of new T1 gadolinium-enhanced lesions per subject per magnetic resonance imaging scan from baseline to 96 weeks.

Cladribine is a small molecule that interferes with the behavior and the proliferation of certain white blood cells, particularly lymphocytes, which are involved in the pathological process of MS. Through its differentiated mechanism of action, oral cladribine may offer a safe and effective new option to patients with MS. Rebif is a disease-modifying drug used to treat relapsing forms of MS and is similar to the interferon beta protein produced by the human body. Interferon helps modulate the body's immune system, fight disease and reduce inflammation, according to the company.