An open trial of long-term testosterone suppression in spinal and bulbar muscular atrophy.
We investigated the long-term effects of leuprorelin on leg-muscle strength in spinal and bulbar muscular atrophy (SBMA). We hypothesized that testosterone suppression by leuprorelin would prevent the progression of muscle weakness.
In a prospective, long duration, open trial, 16 SBMA patients underwent medical castration with leuprorelin for 3.5 years. Chlormadinone was coadministered initially to prevent a testosterone surge. The strength of knee extension and flexion were quantitated using a torque machine.
Our hypothesis was rejected. The leg strength measures decreased significantly with the mean reduction of 22.3-27.8%. In a post hoc analysis, the leg strength of 4 patients with higher pretreatment baseline total testosterone levels and short disease duration of 1-6 years were stronger at baseline and decreased by only 12.3-15.7% after treatment.
Leuprorelin was not effective in this small long-term treatment trial in SBMA. The possibility that earlier treatment might be beneficial may deserve further study.