Ozarelix improved peak flow rate, but did not have an effect on erectile function, researchers say.


PARIS—Ozarelix, an investigational agent, may be effective for selected men with lower urinary

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tract symptoms (LUTS) associated with BPH, phase II trial data suggest. The drug is a highly soluble luteinizing hormone releasing antagonist.


The study, led by Bela Denes, MD, senior director of clinical research and development of the ozarelix development team for Spectrum Pharmaceuticals, evaluated the treatment in men at least 50 years old with an International Prostate Symptom Score (IPSS) of 13 or higher at screening and a peak flow rate of 5-13 mL/sec.


Patients were divided into five treatment groups: placebo (24 patients) or one of four dosing regimens of ozarelix: 5 mg at day 1 and 15 (30 patients), 10 mg at day 1 and 15 (30 patients), 20 mg at day 1 (30 patients), and 15 mg at day 1 and 15 (29 patients). The data from placebo responders were dropped from the study. The researchers measured efficacy using patient-completed IPSS and International Index of Erectile Function (IIEF)-5 surveys.


The investigators observed a transient testosterone decrease that rapidly returned to baseline in all treatment groups. “It appears that a separated dose is more efficacious than a single injection,” Dr. Denes said. “Some of the pharmacokinetic and pharmacodynamic studies suggest that the first dose drives testosterone down, but you need a second dose to maintain suppression of testosterone for that short, transient period of time.”


The most efficacious ozarelix regimen was 15 mg at day 1 and at day 15 (15+15). The 15+15 dose was associated with significant improvement in IPSS over placebo at four weeks, Dr. Denes said. At 12 weeks, the re-searchers observed an eight-point separation between IPSS and placebo, and this was maintained out to six months. Additionally, the peak flow rate increased by 3.5 mL/sec in the 15+15 group at 28 weeks.


“Prostate volume was transiently decreased but returned to baseline by eight weeks,” Dr. Denes said. Ozarelix was well tolerated in all dose groups. IIEF surveys revealed no change in erectile function from baseline in any of the treatment groups.


The study demonstrates that the effects of a single dosing regimen consisting of two injections on days 1 and 15 are maintained for up to six months, “which is superior to what is usually seen with currently approved drugs for BPH,” said Rajesh C. Shrotriya, MD, CEO of Spectrum Pharmaceuticals.


Findings were reported here at the Société Internationale d’Urologie 29th Congress