107 Preservation of Normal Concentration of Pituitary Gonadotropins Despite Achievement of Normal Serum Testosterone Levels in Hypogonadal Men Treated with 4.5% Nasal Testosterone Gel (Natesto)

Abstract

One well-recognized limitation of standard testosterone treatments is impaired spermatogenesis via suppression of the pituitary hormones, follicle-stimulating hormone (FSH) and luteinizing hormone (LH). We report here the results of treatment with a 4.5% intranasal testosterone gel (Natesto®), on serum total testosterone (TT), LH, and FSH in hypogonadal men. Hypogonadal men were randomized into a 90-day, open-label, dose-ranging study. 4.5% intranasal testosterone gel (125 uL/nostril, 11.0mg testosterone/dose) was self-administered using a multiple-dose dispenser either twice daily (BID, n=122) or 3 times a day (TID, n=151) for a total dose of 22.0mg or 33.0mg, respectively. Titration was performed based on blood levels so as to achieve the eugonadal range (300 -1050 ng/dL). Serum samples were obtained at baseline and after 90 days of treatment to determine relevant hormone levels. Total serum testosterone increased from a mean Cavg 200.8 ng/dL at baseline to a mean Cmax 818.49 ng/dL at ∼40 minutes. After 90 days, 90% (95% CI = 83-97%) of men in the TID group, and 71% (95% CI = 62-79%) of men in the BID group reached normal T levels, and a mean total testosterone Cavg 421 ng/dL and 375 ng/dL, respectively. Baseline FSH (BID) was 8.49 IU/L, mean at Day 90 was 5.99 IU/L. Baseline FSH (TID) was 6.42 IU/L, mean at Day 90 was 3.12 IU/L. Baseline LH (BID) was 5.42 IU/L, mean at Day 90 was 3.56 IU/L. Baseline LH (TID) was 5.25 IU/L, mean at Day 90 was 2.20 IU/L.