Evaluation of the efficacy and tolerability of alendronate versus denosumab in kidney transplant patients with reduced bone mineral density.

Purpose: To compare the effect of denosumab and alendronate on bone mineral density (BMD) in renal transplant recipients (RTRs) with low bone mass.

Methods: Patients were randomized to receive either denosumab subcutaneously (60 mg/6 months), oral alendronate (70 mg/week), or no treatment for 1 year. The three groups were prescribed daily calcium and vitamin D. Primary outcome was BMD assessed at lumbar spine, hip, and radius and measured by dual-energy X-ray absorptiometry (DEXA) at baseline and after 6 and 12 months. Adverse events and laboratory assessments (calcium, phosphate, vitamin D, renal functions, and intact parathyroid hormone) were monitored for all patients. Quality of life was assessed at baseline and after 6 and 12 months for all patients.

Results: Ninety RTRs were included in the study (30 in each group). Baseline clinical characteristics and BMD values were comparable in the three groups. After 12 months, lumbar spine T-score of patients treated with denosumab and alendronate showed a median increase of 0.5 [95% confidence interval (CI): 0.4-0.6] and 0.5 (95% CI: 0.4-0.8), respectively, and patients in the control group showed a decrease of -0.2 (95% CI: -0.3 to -0.1), p < 0.001. Denosumab and alendronate showed a significant comparable gain in T-scores at hip and radius versus a significant decrease in the control group. Adverse events and laboratory values were similar in the three groups. Both treatments resulted in comparable significant improvement in physical functioning, physical role limitations, vitality, and pain scores.

Conclusion: Denosumab and alendronate showed comparable efficacy in improving BMD at all measured skeletal sites and were safe and well-tolerated, with no serious adverse effects reported in RTRs with low bone mass. The study was registered on ClinicalTrials.gov, number NCT04169698.