Inclusion Criteria:

- Histologically or cytologically confirmed adenocarcinoma of the prostate

- Known hormone refractory disease

- Multiple skeletal metastases (≥ 2 hot spots) on bone scintigraphy

- No intention to use cytotoxic chemotherapy within the next 6 months

- Either regular (not occasional) analgesic medication use for cancer related bone pain
or treatment with EBRT (External Beam Radiation Therapy) for bone pain

Exclusion Criteria:

- Treatment with an investigational drug within previous 4 weeks, or planned during the
treatment period

- Eligible for first course of docetaxel, i.e. patients who are fit enough, willing and
where docetaxel is available

- Treatment with cytotoxic chemotherapy within previous 4 weeks, or planned during the
treatment period, or failure to recover from adverse events due to cytotoxic
chemotherapy administered more than 4 weeks ago

- Systemic radiotherapy with strontium-89, samarium-153, rhenium-186 or rhenium-188 for
the treatment of bony metastases within previous 24 weeks

- Other malignancy treated within the last 5 years (except non-melanoma skin cancer or
low-grade superficial bladder cancer)

- History of visceral metastasis, or visceral metastases as assessed by
abdominal/pelvic CT or chest x-ray within previous 8 weeks