Does the dosing and delivery site make a difference in the effectiveness of ADT?

The first LHRH agonist drug to come on the market for ADT was leuprolide acetate, which is now available as depot injections intended to last for 1–month, 3-months, 4–months or 6-months. In North America, leuprolide acetate is marketed under the names of Lupron or Eligard.

Leuprolide acetate can be delivered in microspheres injected intramuscularly or as biodegradable solid depot deposited into subcutaneous fat. This paper (which was funded by one of the drug companies marketing the drug) explores the relative effectiveness of the different formulations. Although all the LHRH drugs can suppress testosterone (T) to < 50 ng/dl, greater T suppression is better. The authors conclude that solid depot can "reliably suppress T to less than 20 ng/dl in >90% of patients”. This doesn't mean the intramuscular depot is necessarily inferior.  What it means from a patient perspective is that, if one is using long-lasting depots of any LHRH drug, they should probably get their T-levels checked whenever they get a PSA test to ensure that they are getting adequate T suppression.


Crawford ED, Moul JW, Sartor O, Shore ND. 2015. Extended release, 6-month formulations of leuprolide acetate for the treatment of advanced prostate cancer: achieving testosterone levels below 20 ng/dl. Expert Opin Drug Metab Toxicol 11(9):1465-1474.