Blissel is adminstered once daily for 3 weeks, then twice weekly for maintenance treatment. Each 1g application provides 50 microgram estriol; existing topical estriol formulations listed in MIMS provide 1mg/g or 100 microgram/g of the hormone.
In a double-blind placebo-controlled trial, 167 postmenopausal women with vaginal atrophy were randomised to receive either 1g of vaginal gel containing 50 microgram of estriol or 1g of placebo (vehicle) gel, daily for 3 weeks and then twice weekly for a further 9 weeks.
After 12 weeks of treatment, women receiving estriol gel (n=114) showed significant improvements in the maturation value of vaginal epithelium and vaginal pH compared with those receiving placebo (n=53; p < 0.001 for both endpoints). There were also significant improvements in signs of vaginal atrophy such as fragility, dryness and pallor of the mucosa and flattening of folds.
For the patient-reported symptoms, assessed as secondary endpoints, statistical significance versus placebo was reached for vaginal dryness after 12 weeks of treatment, but not for dyspareunia, vaginal pruritus, burning or dysuria. Nevertheless the mean global symptom score at week 12 was significantly lower in women treated with estriol than in those who received placebo (p=0.02).
In total 88.2% of estriol-treated patients reported improvement or resolution of vaginal dryness compared with 66.7% of patients who received placebo (p=0.001).
The authors highlighted the hydrating properties of the estriol gel vehicle, which was used (without the active ingredient) as the study placebo and could have contributed to the lack of significance achieved for some of the patient-reported endpoints.
Overall 73.6% of patients in the estriol group considered the gel's effectiveness as excellent or good, compared with 43.1% of those in the placebo group.
Treatment-related adverse events were similar in the two groups.
Quality of life
In another study in 68 postmenopausal women with vulovvaginal atrophy who were treated with estriol 50 microgram/g gel for 12 weeks, there were significant improvements from baseline in somatic aspects of quality of life (p < 0.05) and sexual health.