Repros' testosterone drug succeeds in small study, shares soar
Reuters staff
2 min read

Oct 7 (Reuters) - Repros Therapeutics Inc RPRX.O said its experimental drug Androxal restored normal sperm counts while boosting testosterone levels in an exploratory study, sending its shares nearly tripling.

This small study involved men with secondary hypogonadism who were undergoing testosterone replacement therapy. Secondary hypogonadism is a condition in which the male hormone testosterone falls below the normal range.

The company said it hopes to submit a request for a meeting with the U.S. Food and Drug Administration to determine whether the agency believes the observations are clinically relevant and whether a development program can be designed to confirm the results of this exploratory study.

The study was designed to compare Androxal with Auxilium Pharmaceuticals Inc's AUXL.O gel Testim for treating low testosterone.

Overall, Androxal treatment in this study was well tolerated, with few reported side effects, Repros said.

Last month, the company said U.S. health regulators requested more data on its lead drug, Proellex, to resolve a clinical hold on it. [ID: nBNG404732]

Shares of the company closed at 89 cents on Nasdaq Tuesday, after trading at $2.55 in premarket trading.

Methods and Subjects: We measured IGF-1 and pituitary hormone levels in men with secondary hypogonadism treated with enclomiphene (also known as Androxal) and compared them with topical testosterone (T) or placebo . Three randomized, blinded phase II studies were conducted to evaluate daily oral Androxal: ZA-201 investigated 12 men taking 25 mg of Androxal compared with men taking the gel for 6 months, and ZA-202 included ZA-204 investigated 119 men with diabetes who took 12.5 or 25 mg of Androxal versus placebo for 3 months, and ZA-204 investigated 47 men who took 6.25 mg, 12.5 mg, and 25 mg of Androxal versus another gel for 3 months. 6 weeks. All subjects had initial total T 350 ng/dL and low to normal LH (12 IU/L). Serum samples were collected before and after dosing for T, LH, and FSH. We couldn't measure hGH directly, but we did measure its marker, IGF-1 produced by the liver.

Results: All treatments raised T to the normal range (300-1000 ng/dL), but placebo in ZA-202 did not. Androxal increases LH and FSH. The gel strongly reduces LH and FSH. Unexpectedly, Androxal had a strong effect in lowering serum IGF-1 in all three trials. Both Androxal and topical agents lowered serum IGF-1, but Androxal was more effective. An example is given in ZA-204 below. The dose groups showed no difference in IGF-1 before treatment (p = 0.94), but a significant difference after treatment (p = 0.03),

Conclusions: The endocrine profile androxal suggests that enclomid citrate stimulates the pituitary gland leading to increases in LH and FSH and ultimately T elevation. The IGF-1 results cannot be attributed to T because when applied topically, T was raised but not IGF-1, whereas only enclomiphene citrate raised T but lowered IGF-1. Enclomiphene citrate, unlike topical medications, may be a novel approach to alleviate low T in men with an intact hypothalamic-pituitary-testicular axis. If Androxal can lower hGH or IGF-1 in older men at risk for prostate cancer, then its use in men with secondary hypogonadism would be an important new therapy.