High dose biotin is being investigated in progressive multiple sclerosis (MS); it is administered orally at 100 mg three times a day. Biotin is a co-factor required for energy production and fatty acid synthesis. Repair of myelin and protection of axons are important therapeutic goals in progressive MS. MS-SPI, the first trial of MD1003 in progressive MS, demonstrated significant sustained disability improvement (Tourbah et al., 2011).

There was no evidence of increased spinal cord remyelination in any biotin-treated group. Hanging wire performance was preserved compared to the start of biotin treatment in the 180 DPI biotin-treated group (P=0.43), but not in controls (P=0.0053). There was a trend (P=0.09) toward preservation of large caliber thoracic level myelinated spinal cord axons. A dose dependent improvement in hanging wire performance was observed in the 3 biotin-treated 45 DPI groups (P=0.02) along with an increase in myelinated spinal cord axons compared to controls.