The therapeutic effect of a new ultra low concentration estriol gel formulation (0.005% estriol vaginal gel) on symptoms and signs of postmenopausal vaginal atrophy: results from a pivotal phase III study

Objective: The aim of this study was to evaluate the efficacy and safety of a new low-concentration estriol formulation (0.005% estriol vaginal gel), providing an ultra low dose of estriol per application (50 mu g), for the local treatment of postmenopausal vaginal atrophy. Methods: Postmenopausal women with symptoms and signs of vaginal atrophy were enrolled in a prospective, double-blind, placebo-controlled study. Women received either 1 g of vaginal gel containing 50 mu g of estriol or placebo gel, daily for 3 weeks and then twice weekly up to 12 weeks. A cytological vaginal study, evaluation of vaginal pH, and assessment of symptoms and signs of vaginal atrophy were performed, and changes between baseline and weeks 3 and 12 were assessed. Adverse events were recorded. Results: A total of 167 women were included (114 received estriol and 53 received placebo). After 12 weeks of therapy, a superiority of estriol compared with placebo gel was shown in the change in maturation value and vaginal pH (P < 0.001 and P < 0.001, respectively). The superiority of estriol was well demonstrated in improvement of vaginal dryness (P = 0.001) and the Global Symptom Score (P = 0.018). Estriol gel proved also superior in the improvement of several of the most outstanding vaginal signs of vaginal atrophy evaluated. After 3 weeks, estriol gel also showed a superiority over the placebo gel in most symptoms and signs evaluated. Treatment-related adverse events were similar among groups. Conclusions: 0.005% Estriol vaginal gel, a new formulation providing an ultra low dose of estriol per application, was shown to be safe and effective in the treatment of postmenopausal vaginal atrophy.