Degarelix

Firmagon, FE200486, degarelix acetate

Sexual health, hormones & signalling

Awaiting medical reviewEN ES DE FR PT ZH+ Follow for updates

Note on this profile. Degarelix is an approved prescription medicine in the US, EU, UK, Australia and elsewhere, not a research-only compound. This page explains the published science. Use outside a prescription carries real risks discussed below.

1What it is

Degarelix is a GnRH antagonist — a competitive blocker of the receptor, rather than an over-stimulating . First- and second-generation antagonists caused histamine release and were unusable; degarelix, developed by Ferring, solved that with a heavily modified decapeptide that forms a gel depot under the skin and releases slowly over a month. It is approved for advanced hormone-dependent prostate cancer. Its practical advantage over agonists is speed and the absence of the testosterone flare: no anti-androgen cover is needed and castrate levels are reached in about three days rather than three to four weeks.

It has no community or self-directed use.

2How it's thought to work

Degarelix occupies the GnRH receptor without activating it. Pituitary release of LH and FSH stops almost immediately; testicular testosterone production falls to castrate range in 96% of men by day 3. FSH is suppressed more deeply than with , which may matter for prostate tissue that expresses FSH receptors. Because there is no receptor down-regulation, suppression is maintained only while drug is present, and testosterone recovers relatively quickly after stopping.

A GnRH antagonist that blocks the pituitary receptor outright. Testosterone falls to castrate level in days rather than weeks, and there is no initial surge.Schematic — not to scale

3What the research shows

Testosterone suppression versus leuprolide (CS21)

A 12-month, randomised, open-label phase 3 trial in 610 men compared degarelix (240 mg loading then 80 mg or 160 mg monthly) with leuprolide 7.5 mg monthly. Degarelix was non-inferior for maintaining testosterone ≤0.5 ng/mL from day 28 to day 364 (97–98% vs 96%), suppressed testosterone far faster (96% castrate at day 3 vs 0% for leuprolide), lowered PSA faster, and produced no flare (Klotz 2008, BJU Int). The extension study (CS21A) followed men up to 5 years and reported durable suppression and a lower rate of PSA progression in the first year, a signal that has not been confirmed in an adequately powered survival trial (Crawford 2011, J Urol). [1][2]

Graded A (inconclusive)

Cardiovascular safety versus agonists

A pooled analysis of six trials suggested fewer cardiovascular events with degarelix than with in men with pre-existing cardiovascular disease (Albertsen 2014, Eur Urol). The prospective PRONOUNCE trial, designed to test this directly, randomised 545 men with atherosclerotic cardiovascular disease to degarelix or leuprolide for 12 months; it stopped early for slow enrolment and found no significant difference in major adverse cardiovascular events (5.5% vs 4.1%) (Lopes 2021, Circulation). The question remains open. [3][4]

Graded A/B

Intermittent and neoadjuvant use, 3-monthly formulation

Trials of a 3-monthly 480 mg formulation showed comparable suppression (Ozono 2018, Cancer Sci †). Short neoadjuvant courses before radiotherapy and radical prostatectomy have been studied with intermediate endpoints.

Lower urinary tract symptoms, benign prostatic hyperplasia

Early-phase studies explored low-dose degarelix for symptomatic BPH; development did not continue.

4Reported side effects and interactions

Literature-reported

injection-site reactions are the dominant adverse effect — pain, erythema, swelling, nodules — in roughly 35–40% of men, mostly after the larger loading injections and far more often than with ; hot flushes (~25%); weight gain; fatigue; raised liver transaminases (mostly mild and transient); chills and fever occasionally after injection. Class-level effects of androgen deprivation apply: loss of libido, erectile dysfunction, gynaecomastia, bone loss, anaemia, insulin resistance, QT prolongation. Hypersensitivity, including anaphylaxis, is rare.

Community-reported

essentially none documented.

Theoretical. deeper FSH suppression than agonists has unknown long-term consequences.

Interactions. no cytochrome P450 interactions identified; additive QT-prolonging risk with class IA/III antiarrhythmics and other QT-prolonging drugs.

Markers researchers commonly monitor

From the label and prostate-cancer guidelines:

Marker	Why it's watched
Testosterone	confirms castrate suppression; particularly useful with degarelix because suppression depends on continuous drug presence.
PSA	tumour response; rising PSA under castrate testosterone defines castration resistance.
Liver enzymes (ALT/AST)	transient elevations occur; the label advises monitoring in men with liver impairment.
ECG (QTc), electrolytes	in men with cardiac history or on QT-prolonging drugs.
Bone mineral density, HbA1c, lipid panel, haemoglobin	long-term androgen-deprivation effects.
Injection sites	nodules and erythema are common and worth documenting.

Free for everyone. Safety information is never behind a paywall.

5Reconstitution and handling

Supplied as a kit of 120 mg or 80 mg powder vials with pre-filled solvent syringes. at the bedside by a clinician to 40 mg/mL for the loading dose and 20 mg/mL for maintenance, swirled (not shaken) and injected deep subcutaneously into the abdomen within one hour; the gel depot forms on contact with tissue. Not a self-administered or home-reconstituted product; the calculator is not applicable.

6Commonly studied alongside

Leuprolide (the standard comparator; see GnRH analogue profiles #102–#108), goserelin (#212), buserelin (#211), relugolix (the oral non-peptide GnRH antagonist that is its main competitor), abiraterone and enzalutamide (added for castration-resistant disease), radiotherapy.

Informational cross-links. Not stack recommendations.

7Regulatory status by region

Region	Status (checked —)
United States	FDA-approved (December 2008) for advanced prostate cancer
European Union	EMA-authorised (February 2009) for advanced hormone-dependent prostate cancer; 3-monthly formulation authorised in some markets †
United Kingdom	MHRA-licensed; prescription-only
Australia	TGA-registered; PBS-listed
South Africa	SAHPRA registration †
Sport (WADA)	Not named on the Prohibited List; GnRH antagonists are not listed under S2 (which covers releasing factors, i.e. agonists) †

8Open questions

Does antagonist therapy genuinely reduce cardiovascular events compared with in men with heart disease? PRONOUNCE was underpowered.
Whether deeper FSH suppression translates into any oncological benefit.
Head-to-head comparison with oral relugolix on tolerability and outcomes.

9References

1Klotz L et al. (2008). The efficacy and safety of degarelix: a 12-month, comparative, randomized, open-label, parallel-group phase III study in patients with prostate cancer. BJU Int. PubMed
2Crawford ED et al. (2011). A phase III extension trial with a 1-arm crossover from leuprolide to degarelix: comparison of gonadotropin-releasing hormone agonist and antagonist effect on prostate cancer. J Urol. PubMed · DOI
3Albertsen PC et al. (2014). Cardiovascular morbidity associated with gonadotropin releasing hormone agonists and an antagonist. Eur Urol. PubMed · DOI
4Lopes RD et al. (2021). Cardiovascular safety of degarelix versus leuprolide in patients with prostate cancer: the primary results of the PRONOUNCE randomized trial. Circulation. PubMed · DOI
5Firmagon (degarelix) US prescribing information and EMA Summary of Product Characteristics (current). PubMed

References are being resolved to PubMed/DOI identifiers; links search PubMed for the citation until then.

† Being confirmed by our reviewers against current sources.

10Community

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Self-reported side effects Phase 2

Not enough data yet. 0 of the 50 members needed have logged this compound for 4+ weeks. We don't show anything below 50, so no one can be identified.

11Page history

31 Oct 2026Profile published — awaiting medical review

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