FDA steps in after a patient on Antares' 'low-T' drug breaks out in hives

The FDA wants more safety data on Antares Pharma's ($ATRS) testosterone treatment after noting a case of hives in a clinical trial, presenting a costly delay for the company's plans to hit the market.

The issue stems from a safety scare in a Phase II trial on QuickShot Testosterone, Antares' subcutaneous dose of the hormone designed to treat hypogonadism, or low testosterone. In the study, one patient in the treatment arm broke out in hives, a reaction Antares believes was unrelated to QuickShot. The FDA, however, disagrees, and, in light of mounting concern over the safety of so-called low-T treatments, the agency wants Antares to collect more data on the injection to get a better handle on its likelihood of spurring allergic reactions.

That means handing in a safety database of roughly 350 patients who have taken QuickShot, Antares said, including 200 exposed for 6 months and 100 exposed for a year. Based on its existing pool of data and ongoing Phase III trial, Antares figures it will need 6-month results from about 70 additional patients. For now, the company's execs aren't speculating how long that will take or how much it will cost until they meet again with the FDA.

Antares remains on track to post top-line data from QuickShot's Phase III trial later this year, but the FDA's demand for new data will likely delay the company's plans to file an NDA thereafter.

The FDA has recently zeroed in on low-T treatments, taking a hard look at controversial evidence that testosterone therapy can lead to elevated risks of heart attack and other events. In September, a panel of agency advisers voted 14-1 in favor of restricting such drugs to use only in specific medical conditions; currently, they're widely prescribed to men reporting low testosterone levels.

The resulting pinch has made times tough for the many biotechs developing new testosterone-replacement therapies, a class that includes Antares, Repros Therapeutics ($RPRX), Lipocine ($LPCN) and Clarus Therapeutics.

- read the statement