Safety and Efficacy of Avonex in Subjects With Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP)

Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP) is an acquired peripheral neuropathy of unknown origin. The etiology is not well understood but is presumed to be immunological. Evidence for this comes from observed similarities to Guillain-Barre syndrome and from the favorable response with immunomodulatory treatments. CIDP is a peripheral nervous system demyelinating neuropathy that is sometimes a corollary disorder to the central nervous system demyelination of multiple sclerosis (MS. The precise mechanisms underlying the pathogenesis are uncertain, but a number of those mechanisms support a potential role for immunomodulatory treatments such as interferon beta (e.g., Biogen Idec Inc.'s AVONEX). The rationale for the use of AVONEX in CIDP derives from observations on the pathogenesis of the condition and its similarities to MS, the mechanism of action of AVONEX, clinical trials that have been performed in CIDP that support a role for IFN-beta, and the unmet need that currently exists because of availability and safety issues with existing therapies. This Phase 2b study is a dose-ranging study designed to provide scientific evidence regarding the safety and efficacy of AVONEX in CIDP. In addition, the study aims to demonstrate the responsiveness and clinical relevance of changes in the MRC sum score and ODSS in CIDP patients.