Pharmacokinetics, safety and preliminary pharmacodynamic evaluation of DARE-VVA1: a soft gelatin capsule containing tamoxifen for the treatment of vulvovaginal atrophy

Objective: This study aimed to measure safety, systemic pharmacokinetics and preliminary efficacy of a vaginal tamoxifen capsule (DARE-VVA1) among postmenopausal women with moderate-to-severe vulvovaginal atrophy. Methods: This was a randomized, placebo-controlled, double-blind, phase 1/2 study of DARE-VVA1, in four doses (1, 5, 10 and 20 mg). Results: Seventeen women were enrolled and 14 completed the 8-week treatment. DARE-VVA1 was safe. All adverse events were of mild or moderate severity and distributed similarly among active and placebo groups. Plasma tamoxifen concentrations were highest among women using DARE-VVA1 20 mg, but the maximum mean (standard deviation) plasma tamoxifen concentrations on day 1 (2.66 ± 0.85 ng/ml) and day 56 (5.69 ± 1.87 ng/ml) were <14% of those measured after one oral tamoxifen dose. Active study product users had significant decreases from pre-treatment baseline in vaginal pH and proportion of vaginal parabasal cells (p = 0.04 for both endpoints), with women randomized to the 10 mg or 20 mg dose experiencing the largest treatment impact. The severity of vaginal dryness and dyspareunia decreased significantly from baseline with active study product use (p = 0.02 for both endpoints). Conclusions: DARE-VVA1 is safe and results in minimal systemic exposure to tamoxifen. Preliminary efficacy data support further development of this product.