WASHINGTON, D.C.—The FDA has approved the first and only testosterone therapy applied to the underarm.

Axiron topical solution CIII is an androgen indicated for replacement therapy in males for conditions associated with a deficiency or absence of endogenous testosterone.

This new formulation is applied via an underarm applicator. Studies show that antiperspirants or deodorants should not interfere with the efficacy of the product.

“Antiperspirants and deodorants do not affect it, but a stick roll-on must be used first because it could get contaminated,” said Dean Knoll, MD, who is with the Center for Urologic Treatment, Nashville, Tennessee. “This is the first only testosterone gel that can be applied under the arm.”

Dr. Knoll spoke about the product at the 2011 annual meeting of the American Urological Association.

In a Phase 3 clinical study, 155 hypogonadal men were enrolled at 26 clinical research centers and 135 men completed the open-label, 120-day titration investigation. Subjects had a median age of 53 years (range 19-78 years). The mean serum total testosterone level at baseline was 196.6 ng/dL. The primary endpoint of the study was the proportion of subjects with total testosterone levels within the normal range, which was defined as 300-1050 ng/dL at day 120. Eighty-four percent of subjects finished the study within the average testosterone levels in the normal range. Adverse reactions were generally mild to moderate and transient in nature and no serious adverse reactions were reported. 

Two pump actuations are needed to achieve the recommended starting dose of Axiron. This is accomplished by applying one 30 mg pump actuation to each underarm for a total of 60 mg. Dr. Knoll said 72% of the 90 subjects in the U.S. study population achieved normal testosterone levels using the recommended 60 mg starting dose by day 15. In addition, 138 responding patients (75%) finished the study on the recommended 60 mg starting dose.

“This is just another application site and patients may find it a more attractive application site rather than applying it to the thighs or somewhere else like the top of their arms.  The costs won’t be any different,” Dr. Knoll told Renal & Urology News.

Cases of secondary exposure in children and women have been reported with topical testosterone products applied to the abdomen or upper arms, including cases resulting in virilization of children. Children and women should avoid contact with unwashed or unclothed application sites in men using the product. Clinicians should thoroughly discuss these issues with their patients, he said.