Objective: To investigate the safety and efficacy of a transdermal estradiol (E2) spray in women with postmenopausal vasomotor symptoms.
Method: A randomized, double-blind, placebo-controlled, multicenter, parallel-group clinical trial was conducted. Postmenopausal women (N=454) with at least eight moderate-to-severe hot flushes per day applied daily, one, two, or three E2 (90 microliter spray contains 1.53 mg E2) or matching placebo sprays. The primary efficacy endpoints were mean change from baseline in frequency and severity of moderate-to-severe hot flushes at weeks 4 and 12.
Results: All three E2 groups showed a significant decrease in hot flushes at weeks 4 and 12 compared with their placebo groups (P<.010). The mean change in frequency at week 12 was eight fewer flushes per day for women in the E2 groups and between four and six fewer flushes for women in the placebo groups. Women in the three- and two-E2 spray groups demonstrated significant (P<.050) reductions in severity score at weeks 4 and 12; women in the one-spray group showed significant reductions at week 5. At week 12, the majority (74-85%) of women on E2 showed at least a 50% hot flush frequency reduction as compared with 46% in the placebo group. The systemic E2 delivery rates at week 12 were approximately 0.021 mg/d, 0.029 mg/d, and 0.040 mg/d for the one-, two-, and three-spray doses, respectively. Common adverse events were similar to those previously reported with other transdermal products. Treatment-related application site reaction rate was similar to placebo (1.3% compared with 1.8%).
Conclusion: The three dose levels of E2 spray achieved efficacy at 0.021-0.040 mg/d delivery rates. The spray is a well-tolerated, new, convenient method of delivering low-dose E2 transdermally.
Clinical trial registration: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00122200.
Level of evidence: I.