Woodlands-based Repros Therapeutics Inc. recently indicated that the company has completed enrollment on one of its two key clinical trials that were initiated on January 12th, 2014, both of which are part of a head-to-head study on the use of its lead therapy Androxal against leading topical testosterone replacement therapies currently available to patients in the market today. In a press release issued by the company, Repros reported that it has successfully recruited and enrolled 120 subjects for its first trial, ZA-305.
Both trials will seek to study 120 men in groups of 40 for three parallel study arms that will test Androxal; an approved, competing topical gel, and a placebo. In order to garner the highest possible level of quality in data collection, clinicians will conduct all three of the study arms in a blind and “double dummied” scheme, which will allow the men participating in the study to receive an active dose of Androxal along with a placebo. Repros plans for the studies to run for a 17-week duration, which will include 16 weeks of dosing and 1 week of follow-up to gather data for the conclusion of the study.
As part of the study, Repros has sought to enroll men who are at least 60 years of age that exhibit a normal sperm count range at baseline (> 15 million/mL) on two days of separate testing that are separated by at least two days. In addition, the participants must also exhibit morning testosterones of < 300 ng/dL on both of these testing days in order to be qualified to participate in the study.
The results of these studies are key for Repros and Androxal, as they will measure the composite endpoint that the company believes will reveal Androxal to be superior among the proportion of participants who achieve both a normal testosterone level and a normal sperm concentration compared to a placebo and currently used topical gels. The study will also seek to ascertain the equivalence of Androxal compared against a placebo, “in the proportion of subjects who experience an end of study sperm concentration below 15 million/mL. These endpoints will provide a comparison of Androxal to the topical gel from the perspective of normalizing testicular function.”
In order for this composite endpoint to be reached, clinical researchers will look to observe participants who “exhibit normal 24 hour average testosterone levels in the normal range (300-1040 ng/dL), and an average of two sperm counts at the end of the study must remain above the lower bound of the 95% confidence interval for normal male fertility (15 million/mL).” Given the fact that recent previous studies of Androxal have shown great promise in the drug’s application, Repros is confident that “the two trials are suitably powered (90% power, alpha=0.05) to demonstrate the key difference between restoration of normal testicular function with Androxal versus the suppression of male reproductive organ activity typically induced by hormone replacement therapy.”
In addition to these primary endpoints, Repros has also indicated that it will continue to measure efficacy and safety in these trials as well, such as, “excursions of testosterone outside of the normal range as well as impact on testosterone levels after study drug is stopped. Safety assessments will include impact on hematocrit, an important cardiovascular safety marker.”
“We are very pleased with the effort of our internal clinical team, the clinical sites involved in the study as well as the clinical supplies contractor,” said Joseph Podolski, President and CEO of Repros Therapeutics. “It was no small effort to organize and deliver a complicated study that includes placebo for both a gel and capsule product.” He further noted, “We further commend the input from our key opinion leader panel in helping to design the study and our own regulatory/clinical QA group for designing and implementing effective instruments that allowed for rapid screening and selection of appropriate study subjects.”
While ZA-305 is currently enrolled and will commence with testing a 10 clinical sites nationwide, Repros still recruiting for its second study ofAndroxal, ZA-304. The company has indicated, however, that it expects to complete full enrollment over the next few weeks.