Abarelix is primarily used in the treatment of advanced prostate cancer. It functions as a gonadotropin-releasing hormone (GnRH) antagonist, effectively reducing the production of testosterone, which can fuel the growth of prostate cancer cells. This makes it a valuable option for patients who require immediate suppression of testosterone levels, such as those with symptomatic metastatic disease or those at risk of serious complications from a testosterone surge. Abarelix is administered via intramuscular injection and is particularly beneficial for patients who cannot tolerate other forms of hormonal therapy or who need rapid hormonal control. Its use helps manage symptoms and slow disease progression in advanced cases.