September 19, 2008

Merck Serono Initiates Phase III Multiple Sclerosis Trial

Merck Serono, a division of Merck KGaA, has initiated a Phase III trial to evaluate the therapeutic effects of its proprietary oral formulation of cladribine in patients at risk of developing multiple sclerosis.

The trial, called Oracle MS will evaluate the safety and efficacy of two dosage regimens of cladribine tablets versus placebo in the treatment of patients who have experienced a first clinical event suggestive of multiple sclerosis (MS). Cladribine tablets are currently also being evaluated in a fully enrolled Phase III pivotal trial - the Clarity study - for treatment of relapsing forms of MS.

The Oracle MS study is a randomized, double-blind, placebo-controlled, international trial. It will involve more than 600 patients considered at risk of developing MS due to a recently experienced isolated demyelinating event and having magnetic resonance imaging brain scans consistent with early signs of MS. Study participants will be randomized in one of the three arms of the study to receive one of two different dosage regimens of cladribine tablets or matching placebo tablets (1:1:1 ratio).

Patients will be treated for a period of two years (96 weeks), or up to the time when they experience a second attack leading to a diagnosis of clinically definite MS, in which case they would be offered open-label treatment with Rebif 44mcg three times a week for a 96-week maintenance treatment period. Patients who do not convert to clinically definite MS within the initial 96-week period of the study will be eligible to enroll in a 96-week long-term follow-up treatment period.

These maintenance and long-term follow-up periods of the study are intended to assess the effect of early treatment with cladribine tablets on relapses and subsequent treatment response to disease-modifying therapy for relapsing-remitting MS and to evaluate the sustained effect of cladribine tablets in delaying the development of definite MS.

In the study, cladribine tablets are given in two or four treatment cycles in the first year, with each cycle consisting of once daily administration for four to five consecutive days, which means study patients take cladribine tablets for only eight to 20 days during that year. In the second year, two treatment cycles are administered to all patient groups.

The primary endpoint of the Oracle MS trial is time to conversion to MS, according to the McDonald criteria. Other endpoints include time to conversion to clinically definite MS according to the Poser criteria (the main secondary endpoint), assessments of MRI brain scans, and disability progression.