Dose-ranging studies of a novel intranasal estrogen replacement therapy

To study the efficacy and tolerability of Aerodiol, a novel intranasal estradiol spray, and to determine an appropriate dose range.

An exploratory, parallel-group, dose-finding study was followed by a large-scale, double-blind, placebo-controlled study. In the exploratory study, 134 postmenopausal women were allocated to receive a daily dose of 100--900 microg of Aerodiol for 12 weeks. Efficacy was determined by an overall assessment of estrogenization. In the placebo-controlled study, 420 postmenopausal women were randomized to receive 100, 200, 300, or 400 microg of Aerodiol, or oral estradiol 1 or 2 mg, or placebo, daily for 12 weeks. Efficacy was assessed by the Kupperman Index and the number of hot flushes per day after 12 weeks.

In the exploratory study, the level of estrogenization was sufficient for 23% of women in the 100 microg/day group, excessive for 36% of the 900 microg/day group, and good for more than 80% of women receiving 200--600 microg/day. In the placebo-controlled study, the Kupperman Index at week 12 was significantly lower than placebo (P<0.01) for all Aerodiol groups except the 100 microg/day group. The efficacy of Aerodiol 300 microg/day was similar to oral estradiol 2 mg/day. The variability in exposure to estradiol was lower with Aerodiol than with oral estradiol. Aerodiol therapy was well tolerated in both studies. Premature withdrawals were approximately equally distributed among treatment groups in the placebo-controlled study.

Aerodiol was effective in reducing climateric symptoms at doses between 100 and 600 microg/day. Treatment was well tolerated and well accepted. A dose of 300 microg/day is recommended for initiating hormone replacement therapy.