Supplementary Material for: Switching from zoledronic acid to denosumab for bone modification therapy in patients with malignant tumors and renal insufficiency: a retrospective case series and literature review

Introduction: Zoledronic acid is a common treatment for bone metastases in malignancies, but it is contraindicated in patients with severe renal insufficiency due to its nephrotoxicity. Dose adjustments are necessary for those with mild-to-moderate renal insufficiency. Denosumab is not metabolized by the kidney, hence providing an alternative for patients who are unable to receive zoledronic acid due to nephrotoxicity. Case Presentation: In this study, we retrospectively reviewed four patient cases with bone metastases from solid tumors (two breast cancer, one prostate cancer, and one lung cancer), all developed nephrotoxicity during zoledronic acid treatment and subsequently switched to denosumab. Renal function either improved or remained stable following the switch. And a review of the literature related to denosumab was conducted. Conclusion: Patients with abnormal renal function, BRCA1 mutations, or those at high risk of developing skeletal-related events may benefit from denosumab over zoledronic acid. During denosumab treatment in patients with renal dysfunction, attention should be paid to the occurrence of hypocalcemia.