The FDA has approved the use of triptorelin (Trelstar) 22/5 mg, a new twice-yearly formulation for the palliative treatment of advanced prostate cancer. The new formulation is expected to be available next month. A news release from the manufacturer, Watson Pharmaceuticals, notes that it is the first and only six-month intramuscular gonadotrophin-releasing hormone (GnRH) agonist available for this indication. It is also the only six-month GnRH agonist that is stored at room temperature, with no refrigeration needed.
Trelstar 22.5 mg releases triptorelin pamoate over a prolonged period and, in turn, suppresses testosterone production for six months. Developed by Debiopharm Group and first approved in the United States in 2000, Trelstar is currently available in one-month (3.75 mg) and three-month (11.25 mg) forms. The new, longer-acting six-month formulation is designed to be more convenient, while still maintaining tolerability and efficacy.
The drug is administered via the Mixject delivery system, which utilizes a thin (21-gauge) needle, and is therefore easier to administer and to have a low incidence of injection-site pain.