Prostate disease and the pharmaceutical industry

Prostate Cancer

Vaccines for prostate cancer

A recent independent survey of the biotech industry shows considerable activity in the areas of vaccines for prostate cancer. The outer membranes of prostate cells change when they become cancerous – for example, PSA is expressed on the cell membranes in a form called Prostate-Specific Membrane Antigen. The immune system can be boosted so that it recognises these changed molecules and attacks the cancer cells carrying them.

One experimental approach has used a virus called vaccinia into which the gene for PSA had been cloned. When injected into 33 men with rising PSA levels after radical prostatectomy, about half had their PSA levels stabilised and six remained free from disease progression for 11-25 months. Immunity to PSA was demonstrable in most. In another approach, scientists cloned a growth factor called GM-CSF into prostate cancer cells and then, after irradiating them to prevent them dividing, reinjected them into six patients. An immune response resulted which was directed towards the prostate cancer. These are early days, but clearly this type of approach offers hope for the prevention of prostate cancer and even for the treatment of advanced disease if the techniques can be perfected. By late 2000 at least six vaccines were at the pre-clinical stage, two in Phase 1, and eight in Phase 2 clinical trials.