Effect of leuprorelin in bulbar function of spinal and bulbar muscular atrophy patients: observational study for 1 year

Background This study aimed to investigate the effect of androgen suppression therapy using leuprorelin focused on the bulbar function of patients with spinal and bulbar muscular atrophy (SBMA). Methods Genetically confirmed SBMA patients who consented to participate in this observational study were enrolled. Leuprorelin was subcutaneously injected every 12 weeks. Videofluoroscopic swallowing study was performed at baseline and after androgen suppression therapy for 1 year. The primary outcome measures were the changes in the vallecular residue and pyriform sinus residue. The videofluoroscopic swallowing study data were analyzed and interpreted by two experienced physiatrists. Results A total of 40 patients with SBMA were analyzed in this study. The inter-rater reliability testing showed good agreement for the pharyngeal residue (ICC = 0.84) and videofluoroscopic dysphagia scale (ICC = 0.75). The vallecular residue and pyriform sinus residue after swallowing 9 mL yogurt were significantly reduced (26.8 ± 22.6 to 14.6 ± 14.5, p < 0.001, 14.9 ± 16.9 to 7.6 ± 9.9, p < 0.001, respectively). The swallowing subscore of amyotrophic lateral sclerosis functional rating scale-revised improved after androgen suppression therapy (3.3 ± 0.5 to 3.5 ± 0.6, p = 0.041). Conclusions Leuprorelin significantly reduced the pharyngeal residue in patients with SBMA after 1 year of treatment without any serious adverse events and longitudinal studies are needed to confirm these results.