The European Commission (EC) has approved a new indication for enzalutamide for the treatment of adult men with high-risk, non-metastatic, castration-resistant prostate cancer (nmCRPC) based on the results from the pivotal phase 3 PROSPER trial.

This approval follows a positive opinion from the CHMP in September, and makes it one of the first treatments approved for this critical stage of disease, currently associated with a significant unmet medical need.

Enzalutamide was first approved by the EC in June 2013 and is already indicated in the treatment of adult men with metastatic CRPC who are asymptomatic, or mildly symptomatic after failure of androgen deprivation therapy (ADT), in whom chemotherapy is not yet clinically indicated, or whose disease has progressed on, or after docetaxel therapy.

In America, it has already been approved for this indication by the FDA.

The PROSPER trial evaluated enzalutamide plus ADT vs. placebo plus ADT in patients with nmCRPC and rapidly rising prostate-specific antigen (PSA) levels, as defined by a PSA doubling time of 10 months or less and a PSA level of ≥ 2ng/ml.

The trial met its primary endpoint of metastasis-free survival (MFS).

The median MFS was 36.6 months for men who received enzalutamide plus ADT, compared to 14.7 months with placebo plus ADT (n=1401; HR=0.29 [95% CI: 0.24–0.35]; p<0.001).

The PROSPER trial results indicated a 71% reduction in the risk of metastasis or death in men with nmCRPC and rapidly rising PSA levels, compared to placebo plus ADT (HR=0.29 [95% CI: 0.24–0.35]; p<0.001).

Secondary outcomes included a statistically significant delay in the median time to first use of new antineoplastic therapy of 39.6 vs.17.7 months; HR=0.21 [95% CI: 0.17–0.26]; p<0.001 for patients who received enzalutamide plus ADT compared to those who received placebo plus ADT.

Source: Astellas