A combination of Pfizer Inc. and Astellas Pharma Inc.'s Xtandi and a standard hormone therapy reduced the risk of disease progression or death by 71% in men with an early form of prostate cancer.
In a phase 3 trial of 1,400 patients, Xtandi plus androgen deprivation therapy, or ADT, were compared with the hormone therapy alone in patients with non-metastatic castration-resistant prostate cancer.
Patients given the combination survived without the disease spreading to other parts of the body for a median of 36.6 months, compared with 14.7 months for those who were given ADT alone.
In addition, patients on Xtandi plus ADT went for 33.3 months before their disease worsened, a measure known as prostate-specific antigen progression. This compared to 3.9 months for those who were given the hormone therapy alone.
Roughly 9% of men in the combination therapy group discontinued treatment because of adverse side effects versus 6% in the ADT group.
Marketing applications based on the results of the trial have been submitted to the U.S. Food and Drug Administration and the European Medicines Agency. The data is also being submitted to additional regulatory authorities around the world.
Xtandi is currently approved to treat patients with metastatic castration-resistant prostate cancer.
The American Cancer Society estimates about 164,690 new cases of prostate cancer in the U.S. in 2018 and expects about 29,430 to die from the disease.
Pfizer is collaborating with Astellas on the commercialization of Xtandi in the U.S., while Astellas is responsible for developing and commercializing the drug outside the U.S.
