It is important to note that a detailed analysis of study ZA-301, and subsequently reported to the FDA, showed that unlike the suppression of FSH with approved testosterone, Androxal exhibits an increased frequency of sexual activity as determined by reported sexual abstinence. The reduced abstinence period resulted in lower sperm concentrations in some men on Androxal. These findings support those previously reported in the literature that show daily ejaculation results in sperm counts of <50% of baseline after only four successive days of sexual activity.
Study ZA-300 (Androxal Safety Study)
Of the 499 enrolled men, 409 completed the 6 month study. Twenty-eight men withdrew from the study due to adverse events, 8 due to lack of efficacy and the remaining 54 men due to lost to follow-up or procedural issues. The average age of men in the study was 49 with an average BMI of 33. The racial make-up the study was 74% Caucasian, 11% African American, 11% Hispanic, and 4% Other.
Over 50% of the men in the study ZA-300 achieved morning T's greater than 450 ng/dL. At the end of the study approximately 50% of the men were taking the higher 25 mg dose. Over 85% of men achieved testosterone levels within the normal range regardless of dose.The majority of the recorded AE's were deemed mild to moderate in intensity. There was only one subject that developed an SAE that was deemed possibly related to drug. The subject developed a thromboembolism. He was hospitalized and recovered but exhibited multiple risk factors (BMI: 39, height: 6'5", race: African American, family history of DVT and lengthy recent travel) that may have spontaneously led to the event. The most common AE's were related to upper respiratory tract infections (11.6%), but the study was conducted during the cold, flu and allergy season. Other AE's of note included headache (6.6%), muscle spasms (4%), and fatigue (2.8%). Transient blurred vision was noted in 1.4% but changes in visual acuity was noted as an adverse event in only 0.2%. These findings are in line with expectations given the average age of the subjects (approximately 49 years).