Vanishing white matter disease (VWM) is a rare and progressive leukoencephalopathy caused by loss-of-function mutations, in a recessive pattern of inheritance, in any of the genes encoding eIF2B, a guanine nucleotide exchange factor for eIF2 and an effector of the integrated stress response (ISR). At last week’s American Academy of Neurology meeting, Calico Life Sciences LLC and Abbvie Inc. presented preclinical results for their brain-penetrant compound ABBV-CLS-7262 (fosigotifator sodium tromethamine) in VWM.