NEFL and amyotrophic lateral sclerosis: In particular, ibudilast was ineffective in inhibiting microglia activation in the primary motor cortex of ALS patients, which was evaluated by PBR28-PET in 12–24 weeks, and as well as this, the serum neurofilament light chain (NfL) levels, an indicator of neuronal axonal loss, remained unchanged over 36–40 weeks [49].