The US Food and Drug Administration has approved Shionogi's Osphena to treat women experiencing pain during sexual intercourse.

The drug treats dyspareunia, a symptom of vulvar and vaginal atrophy (VVA) associated with declining levels of oestrogen during menopause. Osphena, (ospemifene) is a pill taken with food once-daily which acts like oestrogen on vaginal tissues to make them thicker and less fragile.

The approval is based on three studies of 1,889 postmenopausal women who were randomly assigned to receive Osphena or placebo. After 12 weeks of treatment, results from the first two trials showed a statistically significant improvement of dyspareunia in Osphena-treated women and data from the third 52-week study support its long-term safety.

Osphena's green light comes with a boxed warning which notes that the drug can stimulate the lining of the uterus and cause it to thicken, which is not normal in ostmenopausal women. Patients should see their doctor if they experience any unusual bleeding as it may be a sign of endometrial cancer or a condition that can lead to it. The warning also states the risk of strokes and deep vein thrombosis.

Shionogi quoted David Portman, director of the Columbus Center for Women's Health Research in Ohio, as saying that while more than half of all women in the USA will experience symptoms of VVA at some time in their postmenopausal life, "the vast majority…are not being treated with a prescription medication because women and their healthcare professionals are not proactively discussing the condition, and its associated symptoms". He added that as an oral medication taken once-daily, "Osphena is a convenient way for postmenopausal women to help treat dyspareunia".

VVA is currently treated with vaginally inserted tablets, creams or rings, which Shionogi has noted can be inconvenient or messy. The Japan-headquartered drugmaker obtained the rights to Osphena from the USA's QuatRx Pharmaceuticals in 2010.