Does Degarelix work?
Yes, in a large controlled trial of 610 men.
Approval rested on the CS21 trial, a 12-month randomized open-label phase 3 study of 610 men with prostate cancer, which showed degarelix kept testosterone at castrate levels in over 97% of men, non-inferior to leuprolide, and did so within three days without the testosterone surge that agonists cause. 12
Klotz and colleagues randomized 610 men with prostate cancer who needed hormone therapy. The men got one of two degarelix regimens or monthly leuprolide for 12 months. The main measure was testosterone at or below the castrate threshold at every monthly check from day 28 to day 364. This held in 97.2% and 98.3% of the two degarelix groups. It held in 96.4% of the leuprolide group. That met the non-inferiority goal. 1
By day 3, about 96% of degarelix patients had castrate-level testosterone. None of the leuprolide patients did. They instead had a brief surge of around 65% above baseline. Prostate-specific antigen (PSA) fell faster with degarelix at days 14 and 28. 1
Evidence checklist
- Randomised controlled trial CS21, randomized open-label phase 3
- Human study over 100 people CS21 enrolled 610 men
- More than one research group Registration trial from one program
- Clinical outcomes, not surrogate markers Testosterone suppression, a surrogate
- Human safety data beyond case reports Trial and label adverse event data
More on Degarelix
Citations
- Klotz 2008, BJU Int: efficacy and safety of degarelix, 12-month comparative randomized phase III study (CS21) doi.org
- Firmagon (degarelix for injection) prescribing information, Ferring, revised 2020 ferringusa.com
- Li 2026, Int Urol Nephrol: interstitial lung disease with antiandrogen agents, FDA adverse event reporting system analysis pubmed.ncbi.nlm.nih.gov
Reference information only, not medical advice. Drawn from the Degarelix article, fact-checked against the cited sources. No dosing anywhere on this site.