The Francis Crick Institute
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Targeting protein homeostasis in sporadic inclusion body myositis

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journal contribution
posted on 2020-06-29, 11:25 authored by Mhoriam Ahmed, Pedro M Machado, Adrian Miller, Charlotte Spicer, Laura Herbelin, Jianghua He, Janelle Noel, Yunxia Wang, April L McVey, Mamatha Pasnoor, Philip Gallagher, Jeffrey Statland, Ching-Hua Lu, Bernadett Kalmar, Stefen Brady, Huma Sethi, George Samandouras, Matt Parton, Janice L Holton, Anne Weston, Lucy Collinson, J Paul Taylor, Giampietro Schiavo, Michael G Hanna, Richard J Barohn, Mazen M Dimachkie, Linda Greensmith
Sporadic inclusion body myositis (sIBM) is the commonest severe myopathy in patients more than 50 years of age. Previous therapeutic trials have targeted the inflammatory features of sIBM but all have failed. Because protein dyshomeostasis may also play a role in sIBM, we tested the effects of targeting this feature of the disease. Using rat myoblast cultures, we found that up-regulation of the heat shock response with arimoclomol reduced key pathological markers of sIBM in vitro. Furthermore, in mutant valosin-containing protein (VCP) mice, which develop an inclusion body myopathy, treatment with arimoclomol ameliorated disease pathology and improved muscle function. We therefore evaluated arimoclomol in an investigator-led, randomized, double-blind, placebo-controlled, proof-of-concept trial in sIBM patients and showed that arimoclomol was safe and well tolerated. Although arimoclomol improved some IBM-like pathology in the mutant VCP mouse, we did not see statistically significant evidence of efficacy in the proof-of-concept patient trial.