FDA stalls approval of Repros' enclomiphene

Shares of Repros Therapeutics (Nasdaq: RPRX) fell more than 27% to $1.74 after it announced it was facing a delay in US approval of its lead product candidate.

Repros said it has received a Complete Response Letter from the US Food and Drug Administration for its New Drug Application for enclomiphene (formerly referred to an Androxal) for the treatment of secondary hypogonadism in overweight men wishing to restore normal testicular function.

In the letter, the FDA stated that, based on recent scientific developments, the design of enclomiphene Phase III studies is no longer adequate to demonstrate clinical benefit and recommended that Repros conduct an additional Phase III study or studies to support approval in the target population. The FDA also noted concerns regarding study entry criteria, titration and bioanalytical method validation in the Phase III program.