Why does PSA continue to rise and prostate cancer disease continue to progress (new tumors develop and existing tumors continue to get bigger) when a man has an immune system treatment to go after their prostate cancer? This issue is probably the major marketing hurdle faced by Dendreon’s Provenge and based on the current statistics from the early trials of Prostvac, it will also plague Bavarian Nordic.

I hear again and again from survivors that they have had Provenge and it failed. What they actually mean is that while they took Provenge and during the immediate time after their infusions their PSA still climbed and scans indicated that their disease was progressing. Concluding that the Provenge treatment failed is simply an error in understanding the nature of the treatment.

Conventional prostate cancer treatments like hormonal therapy and chemotherapy are designed to target the tumors and when they work we see a quick lowering of PSA and often a regression of the disease. Thus, men conclude that the treatment works as they see specific evidences of the effect on the tumor and its environment.

Immune therapy (Provenge and investigational treatments like Prostvac) don’t target the tumor. These types of treatments instead target the immune system by building the immune system and making it sensitive to the prostate cancer. Once the