ALSUntangled #80: ISRIB (Integrated stress response InhiBitor)

ALSUntangled reviews alternative and off-label treatments for people living with amyotrophic lateral sclerosis (PALS). Here we assess ISRIB, a molecule that attenuates the integrated stress response (ISR). The ISR is an intracellular signaling network through which cells normally respond to stress, but in ALS it appears to be overactive, leading to the formation of "stress granules" which some but not all investigators believe can triggerapoptotic cell death. ISRIB can attenuate the formation of these stress granules while still allowing parts of protein synthesis to continue. Pre-clinical data demonstrate that ISRIB is beneficial in cell models of ALS. A small number of patients taking ISRIB in Spain report symptomatic improvements with little or no side effects, though we have not been able to independently verify these benefits. There are no clinical trials evaluating ISRIB in any condition and questions about its solubility and bioavailability have arisen. Currently, we do not have enough evidence to endorse the use of ISRIB for treating ALS. We support further research in disease models and clinical trials to study pharmacokinetics, safety and efficacy.