Myovant has announced successful data from its Phase III HERO study of once-daily, oral relugolix for men with advanced prostate cancer.

On the back of the news, the company is set to file a New Drug Application (NDA) submission to the US Food and Drug Administration (FDA) in the second quarter of 2020, supported by the data.

The trial met its primary efficacy endpoint and all six key secondary endpoints in men with the disease, with 96.7% of men receiving once-daily, oral relugolix achieving sustained testosterone suppression to castrate levels.

Further, the drug demonstrated non-inferiority to leuprolide acetate on sustained testosterone suppression through 48 weeks - 96.7% vs. 88.8% - with a between-group difference of 7.9%. The the pharmacodynamic results also showed no testosterone flare after initiation of relugolix, and mean testosterone levels returned to normal levels within 90 days after treatment discontinuation.

An oral gonadotropin-releasing hormone, or GnRH, antagonist for advanced prostate cancer has “been an aspiration for many years,” said Neal Shore, medical director of the Carolina Urologic Research Center and HERO Program steering committee member. “If approved, relugolix would become the first-of-its-kind oral option for men with advanced prostate cancer.”

Treatment for advanced prostate cancer typically involves androgen deprivation therapy, which reduces testosterone to very low levels, commonly referred to as castrate levels. GnRH agonists, such as leuprolide acetate, or slow-release injections are the current standard of care for medical castration.

However, GnRH agonists may be associated with mechanism-of-action limitations, including the potentially detrimental initial rise in testosterone levels that can exacerbate clinical symptoms, which is known as clinical or hormonal flare, and delayed testosterone recovery if the drug is discontinued.

There are around 47,700 new prostate cancer cases in the UK every year, which equates to around 130 every day. It also accounts for 26% of all new cancer cases in males in the UK.