A study of 91 patients with a rare muscle disease (spinal and bulbar muscular atrophy) found that taking leuprorelin, a hormone-like drug, slowed the loss of function over time compared to before they started the drug.

Although leuprorelin acetate, a luteinizing hormone-releasing hormone agonist, has been approved based on short-term clinical trials conducted in Japan, its long-term efficacy on physical function remains unclear. We aimed to evaluate the long-term therapeutic efficacy of leuprorelin acetate using real-world clinical data through a self-controlled trend-shift analysis. The analysis included 91 genetically confirmed patients with spinal and bulbar muscular atrophy, with follow-up data collected before and after treatment initiation. The functional outcomes assessed included the revised amyotrophic lateral sclerosis functional rating scale (ALSFRS-R) and modified Norris scales, grip power, and serum creatinine levels. Leuprorelin acetate significantly slowed disease progression. For instance, the annual ALSFRS-R decline rate improved from approximately 0.5 points pre-treatment to 0.2 points post-treatment. The subgroup analysis supported the potential benefit of early intervention. These findings highlight the value of leveraging patient registries and post-marketing real-world data to evaluate treatment efficacy in slowly progressive diseases, such as SBMA, where traditional randomized controlled trials are often limited by insufficient statistical power to detect therapeutic efficacy. They also underscore the need for innovative methodologies to assess post-approval drug performance, paving the way for improved clinical outcomes for neurodegenerative diseases.