ZONAGEN TO BEGIN STUDY OF ANDROXAL

Zonagen has received investigational review board approval to launch a Phase III study of Androxal, a once-a-day oral therapy for the treatment of testosterone deficiency resulting from a condition known as secondary hypogonadism. The 200-patient trial will be conducted in the U.S. under an investigational new drug application and will enroll patients at up to 20 clinical sites.

The study is designed to assess both the safety of Androxal and its efficacy in restoring normal pituitary and testicular function in men that are hypogonadal due to secondary hypogonadism. Secondary hypogonadism is a failure of appropriate signaling from the pituitary to the testes. The condition is most common in aging males but can result from a variety of causes, including the use of androgens.

The double-blind study will test two doses of Androxal versus placebo and will include an open-label arm of the commercially available drug Androgel. The dosing is of 24-week duration with an efficacy assessment made at 12 weeks. Initial data after 12 weeks of dosing is anticipated in late summer 2006.