What Is Degarelix Used For? Approved Uses, Per the Label

The Short Answer: One Approved Indication

Degarelix is a prescription medicine. In the United States it is marketed under the brand name Firmagon and is a gonadotropin releasing hormone (GnRH) receptor antagonist indicated for the treatment of patients with advanced prostate cancer. It is supplied as a powder for reconstitution and is given by subcutaneous injection by a healthcare professional. This page describes only what the approved labeling covers and what the published trials behind that labeling reported. This page is for educational purposes only and is not medical advice; consult a licensed physician about any question concerning diagnosis, treatment selection, or whether a particular medicine is appropriate.

Degarelix lowers circulating testosterone by blocking GnRH receptors in the pituitary gland, a strategy generally described as androgen deprivation therapy. A pharmacology review summarizing its profile reported that degarelix binds pituitary GnRH receptors competitively and produces rapid suppression of luteinizing hormone, follicle stimulating hormone, and testosterone without the initial hormone surge seen with GnRH agonists (PMID 26513436).

How the Indication Is Worded

The United States prescribing information for Firmagon describes the product as a GnRH receptor antagonist indicated for the treatment of patients with advanced prostate cancer. The labeling does not divide this into subpopulations by stage beyond the word advanced, and it does not list separate indications for other tumor types or for benign conditions. Labeling is revised periodically by the manufacturer and the FDA, so the current revision date and full wording should be read directly from the version accompanying the dispensed product.

The Pivotal Trial Behind the Indication

The registration evidence came from a 12 month, comparative, randomized, open label, parallel group phase III study in patients with prostate cancer, often referred to as CS21. The study enrolled patients requiring androgen deprivation therapy and compared degarelix with monthly leuprolide, with the primary endpoint being the probability of testosterone suppression at or below the castrate threshold of 0.5 ng/mL from day 28 through day 364 (PMID 19035858). Researchers reported that degarelix met the prespecified criterion for non inferiority to leuprolide on that endpoint (PMID 19035858).

Beyond the primary endpoint, the study reported faster initial suppression of testosterone with degarelix and an absence of the testosterone surge that characterizes the first days of GnRH agonist therapy, along with earlier decline in prostate specific antigen (PMID 19035858). The same report described injection site reactions as more frequent in the degarelix arms than in the leuprolide arm (PMID 19035858). Specific dose amounts and schedules are set out in the prescribing information and are chosen by the treating clinician, so they are not reproduced here.

Regulatory History of the Indication

Degarelix was developed as an alternative to GnRH agonists for achieving androgen deprivation in prostate cancer. The phase III comparison with leuprolide was published in 2008 (PMID 19035858), and United States approval for the treatment of patients with advanced prostate cancer followed in 2008 under the brand name Firmagon. The indication has remained a single prostate cancer indication since then; later labeling updates have addressed formulation and administration details and safety information rather than adding new disease states.

A 2017 review comparing degarelix with luteinizing hormone releasing hormone agonists summarized the clinical development program and the rationale for antagonist therapy, including the avoidance of a testosterone flare at initiation (PMID 28480768). A pharmacokinetic and pharmacodynamic review described the depot behavior of the subcutaneous formulation and the sustained suppression of gonadotropins that follows administration (PMID 26513436).

What Comparative Evidence Reported

A Cochrane systematic review examined degarelix for advanced hormone sensitive prostate cancer and pooled the randomized evidence available at the time (PMID 34350976). The reviewers reported that the certainty of evidence for patient important outcomes such as overall survival and quality of life was low to very low, and that injection site reactions occurred more often with degarelix than with comparator androgen deprivation (PMID 34350976). That review illustrates a recurring theme in this field: most trials were powered for hormone suppression rather than for long term oncologic endpoints (PMID 34350976).

Cardiovascular outcomes were tested directly in the PRONOUNCE randomized trial, which compared degarelix with leuprolide in men with prostate cancer and preexisting cardiovascular disease (PMID 34459214). Researchers reported that the trial closed early because enrollment and event rates were lower than projected, and that no statistically significant difference in major adverse cardiovascular events at 12 months was observed between the two arms (PMID 34459214). The authors noted that the early termination limited the power of the comparison (PMID 34459214).

Adverse Events in Trials: What Studies Report

Adverse event information below is drawn from published trials and reviews and does not replace the full warnings, precautions, and adverse reaction sections of the prescribing information.

• Injection site reactions. The phase III comparison reported injection site reactions, including pain, erythema, and swelling, more frequently with degarelix than with intramuscular leuprolide (PMID 19035858), and the Cochrane review reported the same pattern across pooled trials (PMID 34350976).
• Effects of androgen deprivation. Hot flushes and other consequences of low testosterone were reported among the common events in the phase III program (PMID 19035858), and reviews of antagonist versus agonist therapy discussed these class effects (PMID 28480768).
• Cardiovascular events. The PRONOUNCE trial was designed specifically to compare major adverse cardiovascular events between degarelix and leuprolide and reported no significant difference at 12 months in its prematurely closed cohort (PMID 34459214).

Settings That Are Not Approved Uses

Degarelix has been studied in research settings that fall outside the approved indication, and those settings are not approved uses. Examples in the published literature include the ARNEO randomized phase II trial of neoadjuvant degarelix with or without apalutamide before radical prostatectomy for high risk prostate cancer (PMID 36167599), translational work reporting that androgen deprivation therapy drives a distinct immune phenotype in localized prostate cancer (PMID 39269310), preclinical work on lactate and PD-1 mediated macrophage immunosuppression in PTEN and p53 deficient prostate cancer models (PMID 36862086), and an early pilot study of bipolar androgen therapy that combined androgen suppression with testosterone administration (PMID 25814159). These reports describe investigational contexts only.

Related Androgen Deprivation Trials That Do Not Change the Degarelix Label

Several large trials examined androgen deprivation therapy in combination with radiotherapy, but they tested treatment strategies or other agents rather than expanding the degarelix indication. The RADICALS-HD randomised controlled trial compared adding six months of androgen deprivation therapy to postoperative radiotherapy against radiotherapy alone (PMID 38763154), and a companion analysis compared long course with short course androgen deprivation therapy alongside postoperative radiotherapy (PMID 38763153). A separate analysis examined radiotherapy plus relugolix, an oral GnRH receptor antagonist, in men with localized or advanced prostate cancer (PMID 38451492). These studies inform how androgen deprivation is sequenced in prostate cancer care generally; the approved indication for degarelix remains the single prostate cancer indication described above.

Questions a Prescribing Clinician Can Answer

Every individual question about this medicine belongs with a licensed prescriber who can review the medical record, staging, comorbidities, and the current labeling. Topics that typically come up in that conversation include:

1. Whether androgen deprivation therapy is indicated at all for a specific stage and disease course.
2. How an antagonist compares with an agonist for a particular patient, a comparison discussed in review form (PMID 28480768).
3. What monitoring of testosterone, prostate specific antigen, and cardiovascular health is planned, given that the dedicated cardiovascular trial closed early (PMID 34459214).
4. How injection site reactions reported in trials are managed in practice (PMID 34350976).

Key Points

• Degarelix is a prescription GnRH receptor antagonist marketed in the United States as Firmagon and indicated for the treatment of patients with advanced prostate cancer.
• The pivotal evidence was a 12 month randomized open label phase III study in which degarelix met non inferiority to leuprolide for testosterone suppression (PMID 19035858).
• Reviews described rapid gonadotropin and testosterone suppression without an initial surge (PMID 26513436).
• Pooled randomized evidence for long term oncologic outcomes was reported as low certainty (PMID 34350976).
• Other studied settings, including neoadjuvant use before prostatectomy, remain investigational (PMID 36167599).

For broader background on how peptide based medicines are evaluated for safety, see Are Peptides Safe?

References

• The efficacy and safety of degarelix: a 12-month, comparative, randomized, open-label, parallel-group phase III study in patients with prostate cancer (BJU International, 2008)
• Pharmacokinetic and pharmacodynamic profile of degarelix for prostate cancer (Expert Opinion on Drug Metabolism and Toxicology, 2015)
• Degarelix versus luteinizing hormone-releasing hormone agonists for the treatment of prostate cancer (Expert Opinion on Pharmacotherapy, 2017)
• Degarelix for treating advanced hormone-sensitive prostate cancer (Cochrane Database of Systematic Reviews, 2021)
• Cardiovascular Safety of Degarelix Versus Leuprolide in Patients With Prostate Cancer: The Primary Results of the PRONOUNCE Randomized Trial (Circulation, 2021)
• ARNEO: A Randomized Phase II Trial of Neoadjuvant Degarelix with or Without Apalutamide Prior to Radical Prostatectomy for High-risk Prostate Cancer (European Urology, 2023)
• Androgen Deprivation Therapy Drives a Distinct Immune Phenotype in Localized Prostate Cancer (Clinical Cancer Research, 2024)
• Reversal of Lactate and PD-1-mediated Macrophage Immunosuppression Controls Growth of PTEN/p53-deficient Prostate Cancer (Clinical Cancer Research, 2023)
• From bench to bedside: bipolar androgen therapy in a pilot clinical study (Asian Journal of Andrology, 2015)
• Adding 6 months of androgen deprivation therapy to postoperative radiotherapy for prostate cancer: a comparison of short-course versus no androgen deprivation therapy in the RADICALS-HD randomised controlled trial (Lancet, 2024)
• Duration of androgen deprivation therapy with postoperative radiotherapy for prostate cancer: a comparison of long-course versus short-course androgen deprivation therapy in the RADICALS-HD randomised trial (Lancet, 2024)
• Efficacy and Safety of Radiotherapy Plus Relugolix in Men With Localized or Advanced Prostate Cancer (JAMA Oncology, 2024)