Genzyme Corp. and Bayer Schering Pharma AG began the first of two planned Phase III trials examining the safety and efficacy of alemtuzumab for the treatment of multiple sclerosis (MS).

The CARE-MS I trial (Comparison of Alemtuzumab and Rebif Efficacy in Multiple Sclerosis), a randomized study, will compare alemtuzumab to Rebif (interferon beta-1a) in patients with relapsing-remitting multiple sclerosis (MS). Alemtuzumab will be given in two annual cycles; Rebif will be administered three times per week. The CARE-MS I study will include patients who have been diagnosed with relapsing-remitting MS but who have not yet begun treatment with any MS drug. CARE-MS II is scheduled to begin soon and will enroll patients who have continued to experience relapse episodes while on currently available disease-modifying therapies.

This Phase III program follows positive interim results from the Phase II trial that indicate alemtuzumab-treated patients experienced a statistically significant reduction compared with Rebif-treated patients in the risk for sustained accumulation of disability and the risk for relapse for 24 months.

The CARE-MS I study will enroll as many as 525 patients at approximately 60 medical centers throughout North America, Australia, Latin America, and Europe. The companies anticipate filing for marketing approval of alemtuzumab for MS in 2011.