[Effectiveness and tolerability of zoledronic acid in the treatment of metastatic prostate cancer].

Objectives: To assess the effectiveness and tolerability of zoledronic acid in prostate cancer patients with bone metastases at the hormone-sensitive (HS) and hormone-independent (HI) stages.
Materials and Methods: A nationwide, observational, prospective, open and multi-centre trial was devised, with a total of 218 male patients diagnosed with prostate cancer at the HS stage (36%) or HI stage (64%) who were administered zoledronic acid (4 mg/IV/month for 6 months) in addition to their specific oncological treatment. Effectiveness was assessed by the following means: 1) Assessment of the improvement in pain and mobility; 2) Incidence and time to onset of skeletal-related events (SREs) and 3) Analysis of bone markers. Tolerability was assessed by means of registering the number and type of adverse effects. A satisfaction survey was carried out amongst the patients after the end of the trial.
Results: Out of the 218 patients, 170 (78%) were evaluable for effectiveness. A decrease in pain ratings at rest and during movement was observed in all patients, whether in the HS or HI groups (p < 0.0001). Improved mobility was observed likewise (p = 0.005), as was quality of life. The global incidence of skeletal events was 11.2%, with a time to onset of SREs of 10.7 months. There were no significant differences observed between HS vs. HI patients. Osteolysis markers (N-telopeptide) decreased significantly with the treatment across both the HS and HI groups. For safety reasons. 212 patients were evaluable (97.2%). The incidence of adverse drug reactions was 16% (34/212) and was found to be significantly higher in HS patients (22.4%) compared with HI patients (11.9%). Overall, the tolerability of zoledronic acid was good, with no significant morbidity in either group (HS and HI). 66% of the patients reported feeling satisfied or very satisfied.
Conclusions: Zoledronic acid proved effective in the relief of pain, improving mobility and quality of life as well as reducing or delaying the occurrence of skeletal-related events in prostate cancer patients presenting metastatic bone disease, regardless of the phase, whether HS or HI, they found themselves in. Tolerability and patient satisfaction were rates as good.