Combining desmopressin and docetaxel for the treatment of castration-resistant prostate cancer in an orthotopic model

Background/Aim: Desmopressin is a synthetic analogue of the antidiuretic hormone vasopressin. It has recently been demonstrated to inhibit tumor progression and metastasis in breast cancer models. Docetaxel is a chemotherapy agent for castrate-resistant prostate cancer (CRPC). In this study, the ability of CRPC cells to grow and develop in vivo tumors in an animal model was evaluated, in order to investigate the anti-tumor effect of desmopressin in combination with docetaxel. Materials and Methods: The CRPC cell line PC3 was used for orthotopic inoculation in male athymic nude mice. The mice were randomly assigned to one of the four treatment groups: Control, docetaxel, desmopressin or combination therapy. Following the last treatment, tumors were excised and measured. Blood samples were processed for CTC analysis. Results: Docetaxel treatment resulted in a significant reduction in tumor volume compared to control. The combination therapy resulted in even more significant reduction (31.2%) in tumor volume. There was a complete absence of CTCs in the combination group. Conclusion: Our pilot study demonstrated an enhanced efficacy of docetaxel-based therapy in combination with desmopressin.