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In this open-label study, the authors assessed the pharmacokinetics and safety of ibandronate in patients with multiple myeloma and varying renal function. Renal deterioration was graded at baseline depending on creatinine clearance in 4 stages (0: >80; 1: 50-79; 2: 30-49, and 3: <30 mL/min). Patients (n = 40) received intravenous ibandronate 6 mg (30-minute infusion). Ibandronate excretion and serum levels were measured over 24 hours. Serum creatinine, creatinine clearance, and markers of tubular damage were monitored before ibandronate infusion and at 24 and 72 hours following ibandronate infusion. Ibandronate clearance, AUC(0-24), AUC(0-infinity), serum t((1/2)), and C(max) were calculated. There was a significant positive correlation between ibandronate clearance and creatinine clearance (r = 0.858; P < .00001). The AUC for grade 3 renal insufficiency increased by approximately 60% versus grade 0 (P < .01) but was not significantly different between other grades of renal function. The t((1/2)) did not increase significantly, and peak serum levels of ibandronate were similar for the 4 grades of renal function. Serum creatinine, creatinine clearance, and markers of tubular damage did not change significantly within 72 hours of ibandronate infusion. Despite renal function already being compromised in this patient group, there was no evidence of acute nephrotoxicity with ibandronate.

Hypercalcaemia is a common complication of malignancies associated with bone destruction. Besides, benign diseases as sarcoidosis or hyperparathyroidism may lead to hypercalcaemia. The main principles of modern therapy contain a forced diuresis as well as the application of bisphosphonates. Latter substances bear the danger of developing a renal insufficiency. Here, we report the case of a female patient, suffering from primary hyperparathyroidism with severe hypercalcaemia and calcium levels up to 6 mmol/l, who developed acute renal failure. We treated the patient with forced diuresis and repeated infusions of ibandronate (5 x 6 mg ibandronate). Even if lowering the serum levels of calcium only for a short time after each application, yet we could improve renal function by these means. Only after performing a parathyroidectomy, we could see a sustained decline of calcium levels. This case report supports the results of other publications, that have reported the missing nephrotoxic effect of ibandronate compared to other bisphosphonates.

Bisphosphonates are a potential therapy for osteoclast-mediated bone disease, such as renal osteodystrophy. This study evaluated ibandronate bone-binding in patients with secondary hyperparathyroidism and renal osteodystrophy and examined whether there is a correlation with bone metabolism parameters. Sixteen patients with end-stage renal disease and secondary hyperparathyroidism receiving regular hemodialysis were recruited to this 12-week trial. Intravenous ibandronate 2 mg was administered for 5 min every 4 weeks directly after hemodialysis. Ibandronate levels were measured 15 min after infusion and at trough levels before the next hemodialysis. Serological markers of bone metabolism were also measured. After the first infusion, the peak ibandronate level was 154 +/- 75.1 ng/ml and the trough level was 2.7 +/- 1.7 ng/ml. At week 12, peak and trough ibandronate levels were 164.8 +/- 89.9 ng/ml and 3.2 +/- 2.6 ng/ml, respectively. Ibandronate bone uptake was 98.0% at first application and 98.4% at week 12. In patients with remaining diuresis, ibandronate urine excretion was < 0.001% of the administered dose. There was no correlation of ibandronate bone-binding with parameters of osteoclast activity or parathyroid hormone (PTH). The correlation with markers of osteoblast activity was significant but weak. Ibandronate had a bone-binding capacity of approximately 98% in hemodialysis patients. After repeated dosing ibandronate bone-uptake remained stable and was independent of osteoclast activity or PTH levels. Due to the high bone-binding of ibandronate in these patients, a 2 mg dose of intravenous ibandronate is equivalent to a 4-5 mg dose of ibandronate in patients with normal renal function.