Watson Laboratories Inc. has filed an application to market a generic version of Auxilium Pharmaceuticals’ testosterone gel, Testim. Last year, the testosterone-containing treatment generated revenues of $207.9 million for Auxillium.
Testim is a prescription, topical gel that is applied to the shoulders and upper arms of men. It was approved by the Food and Drug Administration (FDA) in 2002 to treat low testosterone.
In 2009, the FDA announced that it was ordering the manufacturers of Testim and another testosterone gel, AndroGel, to include a boxed warning on the Testim 1% and AndroGel 1% labels. The agency required this action after receiving reports of adverse effects in children who were inadvertently exposed to testosterone through contact with another person being treated with these products.
In 2007, 1.4 million prescriptions for Androgel and 370,000 prescriptions for Testim were dispensed by U.S. retail pharmacies. Despite precautions on the drug’s label to instruct users to wash their hands after using the product and to cover the treated skin with clothing, as of December 1, 2008, the FDA had received reports of eight cases of secondary exposure to testosterone in children ranging in age from 9 months to 5 years. Since then, more reports of secondary exposure have been reported to the FDA.
Adverse events in children included inappropriate enlargement of the penis or clitoris, premature development of pubic hair, advanced bone age, increased libido, and aggressive behavior. In most cases, the signs and symptoms went away when the child was no longer exposed to the gel.
In some cases, symptoms remained and children had to undergo invasive diagnostic procedures. In at least one case, a child was hospitalized and underwent surgery due to a delay in recognizing the underlying cause of the signs and symptoms.
Adverse effects were also noted in women who were exposed to testosterone gel, including changes in hair distribution and acne. Generic versions of these testosterone gels would warn users of the same potential health hazards from secondary exposure.
Auxilium says it will fight Watson’s bid for a Testim generic, adding that it believes the nine patents for Testim expire between 2023 and 2025.