Definition

A subcutaneous injectable suspension formulation containing the acetate salt form of leuprolide, a synthetic nonapeptide analogue of gonadotropin-releasing hormone (GnRH), with potential antineoplastic activity. Upon subcutaneous administration of the leuprolide acetate for injectable suspension TOL2506, leuprolide binds to and activates the gonadotropin-releasing hormone receptor (GnRHR). The continuous stimulation of GnRHR by leuprolide results in both the desensitization of pituitary GnRHR and the inhibition of pituitary secretion of the gonadotropins follicle stimulating hormone (FSH) and luteinizing hormone (LH). In males, this results in a significant decline in testosterone production to castration levels and may inhibit androgen receptor-positive tumor progression. In females, this decreases estradiol production and level, suppresses ovarian function and may inhibit proliferation of estrogen receptor (ER)-positive breast cancer.