* Sole self-administered subcutaneous drug in late-stage trial
* Detailed late-stage study data expected by early 2016 - CEO
* Shares up 6.4 pct (Adds CEO comments, updates shares)
By Natalie Grover
Feb 25 (Reuters) - Antares Pharma Inc said its once-weekly testosterone injection met the main goal in an ongoing late-stage study in testosterone-deficient adult males.
The U.S. Food and Drug Administration asked Antares last month for additional safety data on the drug, to be sold as QuickShot Testosterone, after a patient developed hives in a separate mid-stage trial.
The current late-stage study is testing the drug, known chemically as testosterone enanthate, in 150 patients whose testosterone blood levels are less than 300 nanograms per deciliter.
Detailed results from this trial are expected by early 2016, Antares Chief Executive Eamonn Hobbs told Reuters.
QuickShot Testosterone, or QST, is the only self-administered subcutaneous treatment in late-stage development, giving it an edge over existing injectables that must be administered directly into the muscle by a doctor.
Antares, whose shares were up 6.4 percent at $2.67 at midday on Wednesday, said it had already factored in many of the agency’s January recommendations in the late-stage study.
The company said it could need 70 more subjects exposed to QST for six months to meet the FDA’s requirements.
Antares is in talks with the agency to chart a path to procure the data, which could mean conducting a fresh trial or enrolling additional patients to ongoing trials, Hobbs said.
“I’m personally leaning towards an additional small trial,” he said, adding that the company would like to start as soon as possible pending FDA approval.
Patients in the QST late-stage study will remain on the drug and will be monitored for an additional 40 weeks, but so far there have been no reports of hives, Antares said.
The FDA has become increasingly vigilant about testosterone products after it was revealed late last year that more than a fifth of males prescribed these drugs did not test their testosterone levels before or during treatment.
Prescriptions for low testosterone, or “Low T”, have soared over the past decade as middle-aged men face declining testosterone levels.
Up to Tuesday’s close, Antares’ stock has dipped about 4 percent since Jan. 13, when the FDA asked for additional safety data on the drug. (Editing by Ted Kerr)