A new treatment designed to boost testosterone levels in men, which is not a testosterone replacement therapy, is currently being tested in clinical trials. If data is favorable, the drug could be considered for regulatory approval by the end of the year.
Repros Therapeutics’ Androxal is a single isomer of clomiphene citrate, which is widely prescribed under the brand name Clomid to induce ovulation in women. The drug has been used off-label as a treatment of secondary male hypogonadism, a condition of low testosterone.
Repros is developing Androxal for men of reproductive age with low testosterone due to secondary hypogonadism. Secondary hypogonadism is associated with obesity. Researchers believe that obesity is one of the most common causes of low testosterone in men.
Low testosterone levels can cause symptoms such as low libido, weight gain, muscle loss and fatigue. Testosterone replacement product sales have skyrocketed in recent years leading many to question whether the drug is being given to men who do not have hypogonadism but simply want the benefits of elevated testosterone in their systems. Recent studies, however, have shown that testosterone treatments can increase the risk of heart attacks, strokes and death.
“We believe Androxal is high differentiated from currently marketed testosterone treatments or those treatments in late stage development because it is an oral therapy and it treats the cause of secondary hypogonadism, which is inadequate pituitary hormones. We believe that by treating the cause of secondary hypogonadism, Androxal also has the potential to maintain reproductive status and potentially improve overall metabolic profiles,” the company states on its website. Unlike testosterone therapy, Androxal does not shrink the testes or impede fertility.
Last month, Repros received additional guidance from the Food and Drug Administration (FDA) suggesting three co-primary endpoints for the two ongoing phase III studies on Androxal. The two identical, 17-week, double-blind studies will compare the safety and efficacy of Androxal with a testosterone replacement therapy and a placebo in restoring and maintaining testicular function.
The primary endpoints proposed by the FDA include comparing change in sperm concentration in patients receiving Androxal compared to patients on testosterone treatment, and the proportion of men who obtained a testosterone level in the normal range. The agency also recommended comparing the percentage of men who exhibit sperm and testosterone levels in the normal range at the end of a 16-week trial in men using Androxal compared to men using a testosterone gel and men given a placebo.