The European Medicines Agency has approved Johnson & Johnson's Zytiga as a second-line treatment for patients with advanced prostate cancer.

Zytiga (abiraterone acetate) was fast-tracked by the EMA as the first once-daily oral androgen biosynthesis inhibitor, and has been green lighted for use in combination with prednisone or prednisolone in adult men with metastatic castration-resistant prostate cancer whose disease has progressed on or after a docetaxel-based chemotherapy regimen.

The drug is a new type of treatment for prostate cancer that works by blocking the synthesis of testosterone in all tissues including the tumour itself, not just the testes. 

Patients with late-stage prostate cancer have until recently had few treatment options, but the therapeutic landscape has changed markedly in the last couple of years.

Zytiga joins Sanofi's cytotoxic agent Jevtana (cabazitaxel) - which was launched last year in the same second-line indication. It is also being tested in Phase III trials as a first-line treatment in advanced prostate cancer, and this will put it combination with Dendreon's cancer vaccine Provenge, recently-launched in the USA and due to reach the EU in 2013.

J&J's drug has the advantage of being dosed orally, however, while its rivals are delivered by injection.

Zytiga was approved by the US Food and Drug Administration in June and at the time analysts said they believed the high unmet need among advanced prostate cancer patients means it could be a blockbuster treatment with sales topping $1 billion a year.

In the Phase III trial filed in support of the approval, the treatment was shown to increase survival by four months.

One of the investigators in the trial, Prof. Karim Fizazi of the Institut Gustave Roussy in France said: "the efficacy, safety and ease of use of abiraterone acetate, a medicine that can be taken at home, will address an important unmet medical need for many patients, helping them to live longer with a better quality of life and less pain."

Zytiga was licensed from UK firm BTG, which stands to receive an undisclosed milestone payment following EU approval.