Are there any concerns regarding side effects in changing from denosumab to zolendronic acid or vice versa?

In patients with advanced solid tumors and bone metastases, the anti-resorptive agents, zoledronic acid (ZA) or denosumab (D) are administered to prevent skeletal related events (SREs). The key toxicity of concern is medication-related osteonecrosis of the jaw (MRONJ). While patient and oral health factors are known to be related to MRONJ, the independent effect of sequencing from one agent to the other warrants examination. Switching from ZA to D to vice versa may be considered due to toxicities, financial considerations, and patient preferences. ZA has a high affinity for bone hydroxyapatite while denosumab is a nuclear factor-kappa B (NFκB) ligand RANKL inhibiting monoclonal antibody. Thus, the effect of ZA on bone is prolonged, while th...