Head to head

Leuprolide against Degarelix

Q: What is the difference between Leuprolide and Degarelix?

Leuprolide: A prescription medicine, not a research peptide: a GnRH agonist in clinical use since the 1980s and FDA-approved as Lupron for prostate cancer, endometriosis, uterine fibroids and central precocious puberty. Degarelix: A GnRH antagonist approved in 2008 for advanced prostate cancer. In its 610-patient phase 3, testosterone was at or below 0.5 ng/mL by day 3 in about 96 percent of degarelix patients and in none of the leuprolide patients, and it met non-inferiority over 12 months. Injection site reactions occurred in 40 percent versus under 1 percent with intramuscular leuprolide, and the trial designed to test whether it is safer for the heart was terminated early and found no difference.

Q: Which has stronger research evidence, Leuprolide or Degarelix?

This database does not grade compounds. It counts what was run in people: 2 of the 2 studies cited on the Leuprolide profile were human work, against 3 of 3 for Degarelix. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.

Q: Are Leuprolide and Degarelix FDA-approved?

Leuprolide: FDA-approved (Lupron). Degarelix: FDA-approved on 24 December 2008 under NDA 022201, marketed as Firmagon, for treatment of patients with advanced prostate cancer. No boxed warning. Not approved for localised prostate cancer management outside that indication, for any use in women, or for any use in healthy adults..

A GnRH agonist against a GnRH antagonist for the same job. The agonist causes a testosterone surge in the first days of treatment and the antagonist does not, and that difference was measured directly in the trial that registered degarelix.

Column A

Leuprolide

Leuprolide (GnRH agonist)

A prescription medicine, not a research peptide: a GnRH agonist in clinical use since the 1980s and FDA-approved as Lupron for prostate cancer, endometriosis, uterine fibroids and central precocious puberty.

Column B

Degarelix

Degarelix (Firmagon), GnRH receptor antagonist

A GnRH antagonist approved in 2008 for advanced prostate cancer. In its 610-patient phase 3, testosterone was at or below 0.5 ng/mL by day 3 in about 96 percent of degarelix patients and in none of the leuprolide patients, and it met non-inferiority over 12 months. Injection site reactions occurred in 40 percent versus under 1 percent with intramuscular leuprolide, and the trial designed to test whether it is safer for the heart was terminated early and found no difference.

These two were tested against each other directly

A head to head trial, not two separate records compared by us.

The primary endpoint was met by 97.2 percent, 98.3 percent and 96.4 percent of the degarelix 240/80, degarelix 240/160 and leuprolide groups respectively, meeting non-inferiority. By day 3 testosterone was at or below 0.5 ng per mL in about 96 percent of degarelix patients and in none of the leuprolide patients. Median PSA at days 14 and 28 was significantly lower on degarelix (p < 0.001). Injection site reactions occurred in 40 percent on subcutaneous degarelix against under 1 percent on intramuscular leuprolide (p < 0.001).

What the trial was

12 month, randomised, open-label, parallel-group phase III in 610 men with prostate adenocarcinoma of any stage, median age 72, median testosterone 3.93 ng per mL and median PSA 19.0 ng per mL. Three regimens: degarelix 240 mg subcutaneously in month one followed by monthly maintenance of 80 mg or 160 mg, or leuprolide 7.5 mg intramuscularly monthly. Primary endpoint was testosterone at or below 0.5 ng per mL at every monthly measurement from day 28 to day 364.

What the authors concluded

The authors conclude that degarelix was not inferior to leuprolide at maintaining low testosterone over 12 months, induced testosterone and PSA suppression significantly faster, and removes the need for antiandrogen cover against clinical flare.

Where this result is weak

Open-label, 12 months, and the endpoint is a hormone level rather than survival or symptoms. Speed of suppression matters clinically in a narrow group, men at risk of flare, and this trial was not designed to show a survival difference in anyone. The injection site reaction rate is the trade and it is large. A later trial designed to test whether degarelix is safer for the heart was terminated early and found no difference.

Klotz and colleagues, 12 month phase III (CS21), BJU International, 2008

Side by side, on the facts we can check

Attribute	Leuprolide	Degarelix
Category	Hormone	Hormone
FDA status	FDA-approved (Lupron)	FDA-approved on 24 December 2008 under NDA 022201, marketed as Firmagon, for treatment of patients with advanced prostate cancer. No boxed warning. Not approved for localised prostate cancer management outside that indication, for any use in women, or for any use in healthy adults.
Half-life	~3 hours (depot lasts months)	About 53 days terminal, driven by slow release from the subcutaneous depot.
Molecular weight	1,209.4 Da	About 1632 Da as the free base, per the label. A decapeptide with five D-amino acids.
Mechanism	Continuous GnRH receptor stimulation desensitizes the pituitary, sharply reducing LH, FSH, and downstream sex hormones.	Direct competitive antagonism at the pituitary GnRH receptor. Blocking the receptor stops luteinising hormone and follicle-stimulating hormone release immediately, so testosterone falls within days with no initial surge. This is the mechanistic opposite of the agonists leuprolide, goserelin and triptorelin, which produce their suppression by first overstimulating the same receptor. Degarelix also forms a subcutaneous depot at the injection site from which it releases slowly, which explains both the long terminal half-life and the high rate of local reactions.
Human studies cited	2	3
Legal status, US	FDA-approved, prescription only	FDA-approved, prescription only

open the Leuprolide profile open the Degarelix profile

Frequently asked questions

What is the difference between Leuprolide and Degarelix?

Leuprolide: A prescription medicine, not a research peptide: a GnRH agonist in clinical use since the 1980s and FDA-approved as Lupron for prostate cancer, endometriosis, uterine fibroids and central precocious puberty. Degarelix: A GnRH antagonist approved in 2008 for advanced prostate cancer. In its 610-patient phase 3, testosterone was at or below 0.5 ng/mL by day 3 in about 96 percent of degarelix patients and in none of the leuprolide patients, and it met non-inferiority over 12 months. Injection site reactions occurred in 40 percent versus under 1 percent with intramuscular leuprolide, and the trial designed to test whether it is safer for the heart was terminated early and found no difference.

Which has stronger research evidence, Leuprolide or Degarelix?

This database does not grade compounds. It counts what was run in people: 2 of the 2 studies cited on the Leuprolide profile were human work, against 3 of 3 for Degarelix. Those counts are of our own citation lists and understate any larger literature, and neither is a recommendation.

Are Leuprolide and Degarelix FDA-approved?

Leuprolide: FDA-approved (Lupron). Degarelix: FDA-approved on 24 December 2008 under NDA 022201, marketed as Firmagon, for treatment of patients with advanced prostate cancer. No boxed warning. Not approved for localised prostate cancer management outside that indication, for any use in women, or for any use in healthy adults..

Reviewed Sep 2026. This page sets two published records side by side. It is educational, it is not medical advice, and it contains no dosing protocols or recommendations for personal use.