The purpose of this trial is to investigate whether treatment with this new drug will result in lower testosterone levels in men with prostate cancer. At the same time it will be investigated whether the drug induces side effects, and if so, which ones.

Prostate cancer growth is influenced by the male hormone testosterone. Treatment with drugs that stop the production of testosterone often results in a decrease of the tumor or inhibition of its growth. This is particularly important prior to radiotherapy, since radiation can better be focused on the prostate with as a result less frequent or less severe side effects of the radiation.

Most of the drugs used to date to stop the production of testosterone have the disadvantage that initially they may cause a rise of testosterone levels before the production is effectively blocked. The new drug that will be investigated in this trial is a vaccine. The vaccine offers a different treatment modality since it interferes at a different level of the hormonal axis that drives the testosterone production; it will not cause an initial surge.

In this trial the vaccine will be administered three times, testosterone levels will be monitored for a total period of three months.

Inclusion Criteria:

• pathological confirmed prostatic adenocarcinoma, clinical stage (c) cT1-3, cN0-1/x, cM0
• baseline testosterone levels of > 4 nmol/l
• baseline PSA level of > 10 microg/l
• eligible for hormone therapy
• willingness to comply with the protocol conditions and procedures
• willing and able to give informed consent

Exclusion Criteria:

• clinical evidence of distant metastases
• previous hormonal therapy administered specifically for prostatic carcinoma
• development of another invasive neoplastic disease during the previous 5 years, or concomitant presence of another invasive neoplastic disease, except basal cell carcinoma or squamous cell carcinoma of the skin
• primary or secondary immunodeficiency, including immunosuppressive disease or use of corticosteroids or other immunosuppressive medications
• concomitant administration - or administration during the 12 weeks preceding study inclusion - of immune enhancing medication or testosterone supplements
• concomitant radiotherapy for prostate cancer
• presence of bacterial prostatitis causing a PSA increase during the 8 weeks preceding study inclusion
• simultaneous participation in another clinical trial or participation in a clinical trial involving investigational drugs within 3 months before enrollment into the present study
• BMI > 30 kg/square meter
• previous serious reaction to a vaccine such as angioedema or anaphylaxis