Senshio is indicated for moderate to severe symptomatic vulvar and vaginal atrophy in postmenopausal women who are not candidates for vaginal oestrogen therapy. It is the first non-hormonal treatment specifically licensed for this indication.
Ospemifene has an almost full oestrogen agonist effect on the vaginal epithelium, where it increases cell maturation and mucification. Like the other SERMs raloxifene, tamoxifen and toremifene, ospemifene antagonises the effects of oestrogen on breast tissue. It has a neutral or slight oestrogenic effect in the endometrium and agonist-like activity on bone.
Senshio is formulated as a 60mg tablet which is taken once daily.
Vulvar and vaginal atrophy
The safety and efficacy of ospemifene for the treatment of vulvovaginal atrophy were determined in three randomised, double-blind, placebo-controlled clinical trials involving a total of 1889 women. Two were of 12 weeks' duration; the third was of 52 weeks' duration and primarily assessed safety.
Women included in the two 12-week studies were postmenopausal, aged between 40 and 80 years and generally healthy. Baseline requirements were ≤5% superficial cells in the vaginal smear, a vaginal pH of >5 and at least one moderate or severe symptom of vulvovaginal atrophy.
The four co-primary endpoints, for which change from baseline was assessed, were the percentage of parabasal and superficial cells in the vaginal smear, vaginal pH and the severity of the most bothersome symptom.
In the first trial, the 276 women randomised to receive ospemifene 60mg daily showed significant favourable changes in all 4 co-primary endpoints (including the most bothersome symptoms of dyspareunia and vaginal atrophy) after 12 weeks compared with the 268 women randomised to placebo.
In the second trial, there were significant improvements in the ospemifene 60mg group (n=160) compared with the placebo group (n=154) in all the co-primary endpoints apart from the most bothersome symptom of vaginal dryness, which approached significance.
Ospemifene was well tolerated in all three clinical trials. The most commonly reported side-effects were vulvovaginal candidiasis, hot flushes, genital discharge, muscle spasms, headache and rash.