ANAHEIM, Calif.—Ozarelix, a GnRH antagonist given intramuscularly, is well tolerated and has significant and clinically meaningful efficacy in the treatment of lower urinary tract symptoms (LUTS) secondary to BPH, a study shows.
In addition, the medication—a fourth-generation luteinizing hormone releasing hormone antagonist—had no significant impact on urine flow rates or erectile function.
Researchers in Holland conducted a randomized, double-blind, placebo-controlled, multi-center Phase II dose-ranging study with 144 men (mean age 69.1 years; range 52-85 years). At baseline, the mean International Prostate Symptom Score (IPSS) was 19.8, the mean Qmax was 9.7 mL/sec and prostate size 41.6 cm3.
Men were randomly assigned to one of five treatment groups: placebo; 5 mg ozarelix on day 1 plus 5 mg ozarelix on day 15; 10 mg ozarelix on day 1 plus 10 mg ozarelix on day 15; 15 mg ozarelix on day 1 plus 15 mg ozarelix on day 15 and 20 mg ozarelix on day 1 only. All men were followed for six months.
Men who received the drug reported rapid and noticeable activity four weeks after starting treatment, the researchers reported here at the American Urological Association annual meeting. Maximum benefits were reported at 12-16 weeks and persisted for the entire six-month observation period.
At 12 weeks all ozarelix-treated groups showed improvement, with the greatest improvement in the group receiving 15 mg plus 15 mg on day 15. Testosterone levels declined transiently and then returned to baseline in most subjects by four weeks and in all subjects by six weeks following dosing. No adverse effects on erectile function were observed.
Serious adverse events were reported in four patients (pneumonitis, hypotension, renal colic, and MI); these were not considered treatment related. No systemic allergic reactions were seen and the injections were well tolerated.
“I think it is a very promising agent. There is a lot of excitement of this class of drugs,” said Jed Kaminetsky, MD, one of the investigators. “Many men will probably want to have just two shots and be done with it.”
With ozarelix, injections are less painful and less frequent that other investigational agents, he said. Additionally, although testosterone levels decrease, they return to baseline rapidly, said Dr. Kaminetsky, clinical assistant professor of urology at New York University School of Medicine.