What is Eligard, and how does it work?
Eligard is a long-acting formulation of leuprolide acetate, a gonadotropin-releasing hormone (GnRH) agonist. It works by changing the signaling of the brain-pituitary-gonadal hormone pathway that controls sex hormone production [1].
What happens to testosterone (or estrogen) after starting Eligard?
When leuprolide is first given, it stimulates GnRH receptors and causes an initial rise (“flare”) in luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which can briefly increase downstream sex hormones (for example, testosterone in prostate cancer patients). After continued dosing, the pituitary’s GnRH receptors become desensitized and LH/FSH release falls, leading to a sustained drop in sex hormones [1].
What is the clinical goal of Eligard’s mechanism?
By suppressing LH/FSH and lowering sex hormone levels, Eligard reduces hormone-driven growth signals in hormone-sensitive conditions such as prostate cancer and helps treat other conditions where lowering sex hormones is beneficial [1].
Why does a GnRH agonist cause a “flare”?
The flare occurs because GnRH agonists first activate GnRH receptors rather than turning them off immediately. With ongoing exposure, the pituitary receptors downregulate and become less responsive, which is what produces the longer-term hormone suppression [1].
What patients should know about the mechanism-related flare?
Because the first doses can temporarily increase sex hormones, some treatment plans use short-term anti-androgen therapy in prostate cancer to blunt the flare effect. The exact approach depends on the patient and regimen [1].
Source
- Eligard (leuprolide acetate) prescribing information — mechanism of action