[Anti-androgen therapy for spinal and bulbar muscular atrophy (SBMA)]

Spinal and bulbar muscular atrophy (SBMA), or Kennedy's disease, is an adult-onset lower motor neuron disease caused by the expansion of a trinucleotide CAG repeat encoding a polyglutamine tract within the first exon of the androgen receptor (AR) gene. The testosterone-dependent nuclear accumulation of polyglutamine-expanded AR protein is central to the pathogenesis. This hypothesis is supported by pre-clinical studies showing that testosterone deprivation ameliorates motor neuron degeneration in animal modes of SBMA. In a randomized placebo-controlled multi-centric clinical trial, leuprorelin, which suppresses secretion of testosterone, showed no definite effect on motor functions, although there was the improvement of swallowing function in a subgroup of patients whose disease duration was less than 10 years. Elucidation of the entire disease mechanism, early initiation of therapeutic intervention, and sensitive outcome measures to evaluate drug effect appear to be the key to a successful translational research on SBMA.