Japanese pharmaceutical firm Shionogi’s US subsidiary has started a Phase III clinical trial of Osphena (ospemifene) to treat moderate to severe vaginal dryness, a symptom of vulvovaginal atrophy (VVA) due to menopause.

The drug has also secured approval from the US Food and Drug Administration (FDA) to treat moderate to severe painful sex known as dyspareunia, a symptom of VVA due to menopause.

The trial is designed to evaluate the safety and efficacy of Osphena 60mg once-daily oral therapy in postmenopausal women with vaginal dryness as the most bothersome symptom (MBS) of VVA due to menopause.

"We look forward to the results of this study."

Around 600 postmenopausal women between the ages of 40 and 80 will be included in the double-blind, placebo-controlled trial.

The women will be randomised in a 1:1 ratio for treatment with Osphena or a placebo.

In the trial, safety and efficacy will be evaluated at 12 weeks and participants will be followed for two years.

Shionogi Clinical Development senior vice-president Juan Camilo Arjona Ferreira said: "Vaginal dryness is one of the most common and uncomfortable symptoms of VVA experienced by postmenopausal women.

"We look forward to the results of this study and the potential to offer the women who suffer from this condition an oral, non-hormonal treatment option."

Vaginal dryness is one of the most prominent symptoms of VVA, with nearly 50% of postmenopausal women suffering from the symptom.

VVA is caused by declining estrogen levels during menopause, and results in the thinning and inflammation of the vaginal walls.

Osphena works like estrogen in the lining of the uterus, but can work differently in other parts of the body.

The company noted that taking estrogen alone or Osphena may increase your chance for getting cancer of the lining of the uterus.