Palo Alto, Calif.-based Bayhill Therapeutics reported positive results from a phase IIb trial of BHT-3009 for the treatment of multiple sclerosis. BHT-3009 is a gene therapy drug that delivers DNA that instructs cells to produce myelin basic protein (MBP). Myelin is the phospholipid sheath that surrounds neurons and is the target of many autoimmune diseases such as MS.

This multi-center, randomized, double-blind, placebo-controlled study enrolled 289 subjects with relapsing, remitting multiple sclerosis. The subjects received monthly intramuscular injections of BHT-3009 for one year.

The primary endpoints were brain magnetic resonance imaging (MRI) measures of disease activity including gadolinium-enhancing lesions, T2 lesions and T1 black holes. Subjects in a prospectively defined group with high anti-myelin basic protein (MBP) antibodies in their cerebral spinal fluid (CSF) showed statistically significantly fewer gadolinium-enhancing lesions in their brain after treatment with 0.5 mg BHT-3009 compared to placebo.

Reductions in T2 lesions and T1 black holed were also observed in this population. In addition, significant reductions in several CSF myelin-specific autoantibodies were achieved in all the subjects treated with 0.5 mg BHT-3009 compared to placebo.

Based on the results, Bayhill plans to meet with the FDA to discuss a phase III trial design.

According to the National Multiple Sclerosis Society, MS is believed to afflict 400,000 Americans and 2.5 million people worldwide.