After posting impressive data at the recent American Society of Clinical Oncology meeting in Chicago, Johnson & Johnson has made submissions to regulators in Europe and the USA to expand the label on its prostate cancer drug Zytiga.

The healthcare giant's Janssen unit is asking the US Food and Drug Administration and the European Medicines Agency to consider extending the use of Zytiga (abiraterone) administered with prednisone. Specifically, the firm wants the label to include the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) who have not responded to androgen deprivation therapy and before chemotherapy.

The drug is currently approved in combination with prednisone who have received prior docetaxel-based chemotherapy. The filings is based on interim analyses of a 1,088-patient Phase III study which was unblinded in March and patients in the placebo arm be offered treatment with the drug.

At ASCO, J&J noted that the median radiographic progression-free survival in the control arm was 8.3 months but had not yet been reached in the Zytiga arm because progression events were occurring more slowly in the latter. However, it was estimated that patients on Zytiga would have at least 16 months rPFS and showed "a trend for increased median overall survival", which J&J estimated to be about a 33% improvement compared with placebo (or nine months).

However, some observers were worried about the trial being unblinded on the just the possibility, however high, that Zytiga would have shown a statistically significant benefit if trial had been completed.