(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.

androforce x10The 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 androforce x10 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.

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.

Patients in the QST late-stage study will remain on the product and be monitored for an additional 40 weeks, but so far there have been no complaints of hives, Antares said, adding that the collection of safety data was continuing.

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.