Prostate cancer is the most common cancer among men in Norway with nearly 5000 new cases yearly. Advanced prostate cancer is not curable, but several new treatment alternatives have been developed in recent years.

In this Health Technology Assessment we have compared the relative effectiveness and cost-effectiveness of four drugs used for patients with metastatic castration resistant prostate cancer. The drugs are abiraterone, cabazitaxel, enzalutamide and radium-223. Effectiveness: For all patients, independent of previous treatment, all four intervention drugs compared with passive treatment (follow up time 12 to 49 months):

• probably increase median overall survival (reduce risk of death) by approximately four months
• probably increase the progression free survival period between one to five months
• may cause more serious adverse events (abiraterone, cabazitaxel, radium-223) or there may be little or no difference between the treatment groups (enzalutamide)
• probably improves the quality of life slightly

For all endpoints, we assessed the quality of evidence to be either moderate or low.

Cost-effectiveness:

• All four drug treatments, with the exception of radium-223 for docetaxel-naive patients, are more effective but also more costly than BSC.
• In the docetaxel-naive patients, the incremental cost-effectiveness ratios (ICERs) were NOK 984,163 for abiraterone and NOK 971,465 for enzalutamide.
• In the post-docetaxel patients ICERs were: NOK 789,128 for abiraterone, NOK 809,595 for enzalutamide NOK 993,004, for radium-223, and NOK 1,210,474 for cabazitaxel.

Treatments are considered cost-effective if the willingness-to-pay per extra QALY gained is above the ICER. Substantial price discounts would be necessary for these four drug treatments to be cost-effective at a willingness-to-pay of NOK 500,000.