The US Food and Drug Administration (FDA) has approved Astellas’ Xtandi to treat a type of late stage prostate cancer three months earlier than expected.
Xtandi was already undergoing a priority review from the US regulator, but the FDA’s decision means Astellas and its partner Medivation are now poised to launch the drug in the US in around two weeks.
An oral, once-daily androgen receptor inhibitor, Xtandi (enzalutamide) was approved to treat men with metastatic castration-resistant prostate cancer who have previously received docetaxel.
Stephen Eck, vice president of medical oncology at Astellas Pharma Global Development, said: “We believe Xtandi has the potential to play an important role in the treatment of advanced prostate cancer. We’re eager to work with Medivation to make this much-needed new treatment available to medical professionals and patients in September.”
The drug will enter a market already seeing the launch of new drugs, notably Johnson & Johnson’s Zytiga (abiraterone) which achieved sales of around $200m in the first quarter of 2012, but where further treatment options are still needed.
Xtandi, which was filed for European approval in June, is considered a first-in-class agent because it acts on androgens in three ways: blocking androgen receptors; inhibiting nuclear translocation of the androgen receptor from the cellular membrane; and preventing the association of the androgen receptor with DNA within the nucleus.
“The need for additional treatment options for advanced prostate cancer continues to be important for patients,” said Richard Pazdur, director of the Office of Hematology and Oncology Products in FDA’s Center for Drug Evaluation and Research. “Xtandi is the latest treatment for this disease to demonstrate its ability to extend a patient’s life.”
The FDA’s approval came on the back of a 1,199-patient study that was designed to measure overall survival (the length of time before death) in men receiving Xtandi compared with those receiving placebo.
The median overall survival for patients receiving Xtandi was 18.4 months, compared with 13.6 months for the patients who received placebo.
The clinical trial excluded patients with a history of seizure and other brain conditions, but seizures still occurred in approximately 1 per cent of patients receiving Xtandi, who then stopped receiving Xtandi.
Consequently the FDA insisted as a post-marketing requirement that Astellas and Medivation conduct an open-label safety study of Xtandi (160 mg/day or the recommended daily dose) in patients who are at high risk for seizure. Astellas and Medivation will have to provide the data from this study in 2019.