We believe a large number of men with T deficiency remain untreated or do not adhere to their T-replacement therapy because of dissatisfaction with currently available T-replacement therapies. For example, only 31% and 14% of men continued taking T gels six and twelve months, respectively, after commencing therapy, according to a peer-reviewed study of more than 15,000 men who were receiving T gel.
We believe these low adherence rates result in part from inconvenient application and safety concerns about T gels. In addition, T gels carry a "black box warning" because of their risk of unsafe transference of T to children.
U.S. sales of T-replacement therapies were $1.9 Billion in 2015. T-gels comprised 87% of these sales. There are several currently marketed non-oral T-replacement therapies to treat men with T deficiency in the United States, including once-daily T gels, T injectables, once-daily T patches, buccal patches and subcutaneous injectable pellets. We believe each of these existing therapies has limitations related to safety and ease of use.
- T gels and solutions: T gels and solutions are the most common topical formulations. T gels must be applied daily to broad sections of the upper arms, shoulders, stomach, or thighs. T solutions are applied daily to the axilla. Beyond the mess, inconvenience and potential skin irritation, T gels carry the risk of inadvertent and unsafe transference of T to women and children from contact with the hands or other areas on which the gel has been applied. Accidental exposure to T via a T gel can cause premature puberty in children and changes in body hair or increased acne in women. The FDA requires a "black box warning" for these products due to the potentially severe consequences of T transference to children. Despite these concerns, topical formulations accounted for 89% of the $1.9 billion total sales of T-replacement therapies in the United States in 2015, according to IMS Health.
- T injectables: Testosterone injections contain a T prodrug, such as T-enanthate, or TE, or T-cypionate dissolved in oil, and are given intramuscularly every two to three weeks, typically into the muscle of the buttocks. A longer acting injectable formulation, Aveed®, uses TU as the prodrug in an oily vehicle. It is dosed intramuscularly every ten weeks and has an FDA Black Box warning related to the injection. Intramuscular injections of T may be painful and generally require a visit to a physician's office for administration. Testosterone injections can also result in serum T levels in excess of the upper limit of normal. Because men on this form of T-replacement are subject to wide-ranging levels of T across the multi-week period between injections, they sometimes experience troublesome mood swings.
- T patches: These patches contain T and are applied daily to different skin locations on the body. Common side effects associated with T patches are itching, irritation or discomfort at the application site. Consequently, it is recommended that the patch not be applied to the same site more than once a week.
- Other T delivery methods: In addition to the delivery methods described above, a buccal patch, nasal gel, or subcutaneous injectable pellets are sometimes used in T-replacement therapy. The buccal patch is a small, non-biodegradable patch that is placed twice daily onto a hypogonadal man's gums. Testosterone passes from the patch through the gums into the bloodstream. The primary problem with this route of T-replacement is that the patch does not always adhere properly and must be spit out if it becomes dislodged. When a patch is not in place, T-replacement therapy is not active. Recently, a nasal gel product has been approved for T-replacement. Its proper use requires dosing three times each day and treatment must be temporarily discontinued in the presence of severe rhinitis. Testosterone in the form of subcutaneously injectable pellets is also available. A surgical procedure is required for implantation, and if T-replacement therapy is stopped for any reason, the pellets must be removed surgically.