On Friday, Johnson & Johnson's (JNJ -1.15%) Zytiga received an expanded approval from the European Commission. The drug was previously approved for patients with metastatic castration-resistant prostate cancer who have failed a chemotherapy regimen that contains Sanofi's (SNY 5.90%) Taxotere. The new approval expands the use of Zytiga into patients who have failed androgen deprivation therapy, but who aren't appropriate for chemotherapy yet.

The European Commission's decision is a rubber stamp on the European Medicines Agency's Committee for Medical Products for Human Use's decision in November to recommend the expanded marketing authorization.

The expanded approval is based on a clinical trial of more than 1,000 patients comparing Zytiga, plus prednisone/prednisolone, to placebo, plus prednisone/prednisolone. Patients in the Zytiga arm had a statistically-significant improvement in radiographic progression-free survival, a measure of how quickly a tumor begins to grow. Treatment with Zytiga also produced longer overall survival, although the trial was stopped early, so the difference didn't reach statistical significance.