Oct. 6, 2009 (Business Wire) -- Repros Therapeutics Inc. (NasdaqGM:RPRX) today announced results from an exploratory, efficacy and safety study of its oral investigational product, enclomiphene citrate (Androxal^®), in men with secondary hypogonadism who were receiving testosterone replacement treatment. Secondary hypogonadism is a deficiency state in which the male hormone testosterone goes below the normal range, even in aging men, due to inadequate stimulation of the testes by the pituitary. The study was designed to compare Androxal to Testim^®1% (Auxilium Pharmaceuticals Inc, Malvern, PA), an approved topical testosterone gel, indicated for testosterone replacement therapy in adult males for conditions associated with a deficiency or absence of endogenous testosterone. Transdermal testosterone use has been associated with suppression of pituitary gonadotrophic hormones, luteinizing hormone (LH) and follicle stimulating hormone (FSH), both necessary for stimulating testosterone production and spermatogenesis in the testes. Androxal is an oral therapy intended to restore normal brain-pituitary-testes interaction and thus testicular function in men with secondary hypogonadism.

Study Design

This small trial was designed as a two-center, three-arm, randomized, open-label, fixed dose, active-control, proof-of-principle study in men between 46 and 51 years of age who were treated previously with a topical testosterone gel. Upon qualifying for study participation, and after a three-week wash-out period the men were randomized to one or the other of the first two treatment arms. A third arm was added after the first two arms were fully recruited:

• 3 week wash-out followed by 25 mg Androxal daily for 6 months (Group A);
• 3 week wash-out followed by daily Testim 1% gel for 6 months (Group B);
• 3 months wash-out followed by 25 mg Androxal daily for 6 months (Group C).

All treatments were followed by a 1-month post-treatment follow-up period. Key study parameters were concentrations of serum total testosterone (TT), LH and FSH as well as sperm counts at 3 and 6 months of treatment.

Study Results

Group A vs. B: 7 men were randomized to Androxal and 5 men to Testim. After stopping their previous topical testosterone treatment for 3 weeks, the study subjects had baseline morning mean TT values of 165 ± 66 ng/dL, confirming their hypogonadal state. At 3 and 6 months of treatment, there was a statistically significant increase in mean TT compared with baseline in both treatment groups. TT was not significantly different between the 2 groups at 3 (p = 0.29) and 6 months (p = 0.90). At 6 months, mean TT levels were 545 ± 269 and 525 ± 256 ng/dL for the men receiving Testim and Androxal, respectively.