Firmagon works by binding to gonadotropin-releasing hormone (GnRH) receptors located in our pituitary gland (this is the small, bean-shaped gland situated at the base of our brains that produces hormones that control many of our bodily functions such as metabolism, growth, sexual maturation, and reproduction). By binding to GnRH receptors, Firmagon reduces the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and subsequently testosterone. Testosterone is an androgen hormone that can stimulate the growth of prostate cancer. Firmagon works almost immediately, with an initial injection causing a drop in testosterone levels of 88% after 1 day. Within 3 days, levels had dropped by 94%, and by 28 days, 98%. When given every 28 days, levels of testosterone remain at least 98% below normal.
Firmagon belongs to the class of medicines known as gonadotropin-releasing hormone (GnRH) receptor antagonists.