A randomized, open-label, controlled trial of monthly oral minodronate or semiannual subcutaneous injection of denosumab for bone loss by androgen deprivation in Asian men with prostate cancer: the PRevention of Osteopenia with Minodronate And DEnosumab (PROMADE) study

Bone-modifying agents for bone loss in patients with prostate cancer receiving androgen deprivation therapy; insights from a network meta-analysis

BACKGROUND

The data of head-to-head comparisons of the effect of bone-modifying agents (BMAs) in patients with androgen deprivation therapy (ADT) for prostate cancer without skeletal metastasis is limited. Thus, we conducted a network meta-analysis to compare each BMA for the efficacy of bone mineral densities (BMDs) and the risk of fracture.

METHODS

We performed a network meta-analysis to compare the change of BMDs and the risk of vertebral fracture in the studies included using a random-effect model. The primary outcomes are the change of BMD of the lumbar spine (LS) and the total hip (TH) from the baseline at 1 year from the initiation of the BMA and the risk of vertebral fracture.

RESULTS

We identified and included 15 studies in this analysis. All BMAs except risedronate showed a significant increase of BMD of the LS compared with groups without BMA, among which zoledronate showed the most BMD gain. At TH, bisphosphonates (alendronate, pamidronate, and zoledronate) and denosumab showed significant elevation compared with the no-BMA group. Denosumab was associated with the most BMD gain at the TH. Only denosumab reduced the risk of vertebral fracture (relative risk [95% confidence interval]: 0.40 [0.20-0.81]). Although zoledronate showed the highest BMD gain at the LS, it did not reduce the risk of vertebral fracture in this analysis.

CONCLUSION

Most bisphosphonates and denosumab significantly increased BMD at the LS and the TH in patients receiving ADT for prostate cancer without skeletal metastasis. In particular, zoledronate and denosumab were the most potent BMAs in terms of BMD increment at the LS and the TH, respectively. However, denosumab, not zoledronate, was the only BMA that showed a significant risk reduction of vertebral fracture. We need further studies to examine the change of bone quality and the effect on the risk of non-vertebral and hip fractures.

Deubiquitination in prostate cancer progression: role of USP22

Prostate cancer (PCa) is the leading cause of cancer death in men. With more therapeutic modalities available, the overall survival in PCa has increased significantly in recent years. Patients with relapses after advanced secondgeneration anti-androgen therapy however, often show poor disease prognosis. This group of patients often die from cancer-related complicacies. Multiple approaches have been taken to understand disease recurrence and to correlate the gene expression profile. In one such study, an 11-gene signature was identified to be associated with PCa recurrence and poor survival. Amongst them, a specific deubiquitinase called ubiquitin-specific peptidase 22 (USP22) was selectively and progressively overexpressed with PCa progression. Subsequently, it was shown to regulate androgen receptors and Myc, the two most important regulators of PCa progression. Furthermore, USP22 has been shown to be associated with the development of therapy resistant PCa. Inhibiting USP22 was also found to be therapeutically advantageous, especially in clinically challenging and advanced PCa. This review provides an update of USP22 related functions and challenges associated with PCa research and explains why targeting this axis is beneficial for PCa relapse cases.