The FDA-approved drug edaravone could promote the repair of lesions in neuromyelitis optica spectrum disorder (NMOSD), suggest new data. Researchers derived oligodendrocyte progenitor cells (OPCs) from mouse neural progenitor cells and used them to screen a panel of compounds. Edaravone, a free-radical scavenger, promoted differentiation of OPCs and was selected for further study. In mice with demyelination caused by IgG from people with NMOSD, edaravone treatment was associated with remyelination and ameliorated motor impairment, suggesting that the drug could treat NMOSD.