The European Commission (EC) today approved Astellas’ Xtandi as a second-line treatment for men with late-stage prostate cancer.
Xtandi (enzalutamide) – jointly developed with Medivation – is a first-in-class androgen receptor signalling inhibitor that was approved in the US last September and is one of the flagship projects deriving from Astellas’ recent drive into oncology, which has been spearheaded by the acquisition of OSI Pharmaceuticals in 2010 and various licensing deals.
The EU approval is based on the results of the AFFIRM study, which showed that Xtandi at a dose of 160mg once-daily improved overall survival compared to placebo, with median survivals of 18.4 months and 13.6 months, respectively. As in the US Xtandi is licensed for use in men whose cancer has progressed despite prior docetaxel chemotherapy.
Xtandi has got off to a good start in the US, with Medivation saying recently that it made $57m in the last quarter of 2012 and $75m in the first quarter of this year, a trajectory that almost matches the market-leading prostate cancer drug Zytiga (abiraterone acetate) from Johnson & Johnson (J&J).
Zytiga became one of the fastest-growing oral cancer drugs of all time after its approval in 2011, and the product is already knocking on the door of blockbuster status with sales coming in just a little shy of $1bn last year.
Medivation chief executive David Hung previously said he believes the prostate cancer market is still immature – compared to the breast cancer market for example – and has plenty of growth potential given there are still relatively few treatment options available.
“We think that we will gradually be able to increase the size of the prostate cancer market, much like what we’ve seen in breast cancer of more than 10 years ago,” he told investors earlier this month at the Goldman Sachs annual healthcare conference.
Xtandi is also in a phase III study called PREVAIL looking at its role as a treatment for chemotherapy-naïve prostate cancer patients, which is due to be unblended in the coming weeks, and in early-stage testing for breast cancer.
Zytiga already has a pre-chemotherapy claim on its label, but if the PREVAIL data are positive Astellas and Medivation will be able to compete directly with J&J in the prostate cancer marketplace.