Astellas has been boosted by the news that regulators in Europe have expanded use of its prostate cancer drug Xtandi to include patients who have not yet received chemotherapy.

The European Commission has amended the marketing authorisation for Xtandi  (enzalutamide) to include first-line treatment for men with metastatic castration-resistant prostate cancer (mCRPC) after failure of androgen deprivation therapy. It was originally approved in Europe in June 2013 for mCRPC patients whose disease has progressed on or after docetaxel.

The latest green light is based on the Phase III PREVAIL study which demonstrated that compared with placebo, Xtandi reduced the risk of death by 29% and the risk of radiographic progression or death by 81%. Men treated with the oral, once-daily androgen receptor signalling inhibitor experienced a 17-month delay in the time to initiation of chemo compared to placebo (28.0 months versus 10.8 months).

Bertrand Tombal of the Université Catholique de Louvain and European principal investigator for PREVAIL, said Xtandi “provides a viable treatment option for a broad population of men with mCRPC, regardless of age, or their readiness for chemotherapy”. He added that the decision from the European Commission “is a very important milestone”.

Astellas expects to launch Xtandi in the chemotherapy-naïve setting in the first European countries, including the UK, this month. Astellas partner Medivation got US approval for the pre-chemo indication in September.

The new indication will help Xtandi in its battle for market share with Johnson & Johnson's rival drug Zytiga (abiraterone).