Arimoclomol, a coinducer of heat shock proteins for the potential treatment of amyotrophic lateral sclerosis

Recent years have seen an explosion of research into increasingly prevalent neurodegenerative diseases. Arimoclomol (BRX-220), being developed by CytRx Corp, is an oral therapeutic candidate for the treatment of amyotrophic lateral sclerosis (ALS), the most common form of motor neuron disease. ALS is a fatal, incurable disorder, which can present as sporadic (90 to 95% of cases) or familial (5 to 10% of cases) forms. The etiology of sporadic ALS remains unknown and much of the understanding of ALS pathogenesis has been derived through study of its familial forms; in particular, through study of autosomal dominant mutations in the SOD1 (copper/zinc superoxide dismutase) gene, which cause approximately 20% of familial ALS cases. Under conditions of excessive stress, arimoclomol induces amplification of the cytoprotective heat shock response in order to protect motor neurons from death. Comprehensive in vivo and in vitro studies demonstrated its effect in the prevention of neuronal loss and promotion of motor neuron survival, even after symptom onset. Clinical trials have reported good tolerability and safety. This paper discusses the rationale for arimoclomol use in ALS, the preclinical and clinical evidence collected to date, the likelihood of its promising preclinical results translating to humans, and the relevance of this research for neurodegeneration as a whole.