Ibandronate reduces radiotherapy-resistant metastatic bone pain in patients with solid tumors: A comparison of i.v. and oral formulations

Abstract

19517 Background: Bisphosphonates are used to treat metastatic bone disease (MBD). However, some bisphosphonates are associated with renal toxicity. Ibandronate (IA) is a single-nitrogen, noncyclic bisphosphonate with a renal safety profile similar to placebo in phase III trials. This study compares the effects of i.v. IA 6mg and oral IA 50mg on bone pain, analgesic intake and renal safety. Methods: Recruited patients fulfilled the following criteria: age ≥18, solid tumors with at least one bone lesion, normal renal (serum creatinine ≤1.5mg/dL) and hepatic function, WHO performance status 0, I or II, life expectancy ≥6 months, normal serum calcium or asymptomatic hypercalcemia. Patients were excluded if they were pregnant or lactating, taking nephrotoxic drugs or osteoclast activity modulators. Eligible patients (n=52) were recruited for a two-arm study, with 26 patients per group treated over 6 months. Groups were matched for age, gender, weight, height, blood pressure, site of primary tumor, site and number of bone metastases and number of irradiated sites. Intravenous IA 6mg was administered over 15 minutes every 4 weeks. Oral IA 50mg was administered as a single, daily tablet before breakfast. Studies were ceased on occurrence of new bone events. Primary endpoint was reduction in bone pain and reduced analgesic use. Results: There were no significant differences in patient demographics between the two treatment arms. The percentage of patients receiving i.v. IA that achieved stable or progressive disease was 15.4%; those receiving oral IA attained 11.5% stable or progressive disease. Pain (Brief Pain Inventory questionnaire) and analgesic intake were assessed at baseline, 3 and 6 months. Both i.v. and oral IA caused a significant and sustainable decrease in each of the pain indices (p<0.0005) with no significant difference between i.v. and oral groups. Both i.v. and oral IA treatment led to a trend in decrease of analgesic use. Conclusions: Oral and i.v. ibandronate have comparable efficacy for palliation of bone pain in MBD patients. No significant financial relationships to disclose.