Abstract P1-13-02: Ibandronate Shows Marked Pain Relief and a Favorable Renal Safety Profile — Final Results of a Large-Scale Non Interventional Study in Breast Cancer Patients with Metastatic Bone Disease
Authors: Schmidt M , Hesse T , Lerchenmueller C , Diel IJ 
Published: April 2011

Abstract
Background: In patients (pts) with metastatic bone disease (MBD) due to breast cancer (BC) the incidence of skeletal related events (SRE) and the severity of bone pain are effectively reduced by bisphosphonates (BP), the current standard of care in this setting. As treatment with some BP may adversely affect kidney function, renal safety is a key determinant of BP risk/benefit assessment. Ibandronate (IBA), a BP available in IV and oral formulations, demonstrated sustained effects on skeletal related events (SRE) and bone pain with a low incidence of renal adverse events in randomized clinical trials (RCT). To verify those results under real life conditions, a large-scale non interventional study (NIS) was conducted in Germany.
Patients and methods: In accordance with the terms of the marketing authorization, BC pts with MBD received 6 mg IBA IV every 3-4 weeks or 50 mg of oral IBA once daily (at the physician's discretion) for up to 24 weeks. Pain severity (VAS), use of analgesics (classified according to the WHO analgesic ladder), SRE, and renal function (estimated creatinine clearance, eCrCl; Cockcroft-Gault formula) were recorded in 4-week intervals.
Results: 3515 pts, mean age 63.6 +11.7 years, were evaluated. 2320 (66%) were BP-naïve; 418 (12%) had received prior treatment with IBA, 777 (22%) with other BPs, including zoledronic acid (ZOL) (503; 14%) and pamidronate (256; 7%). At baseline, mean pain severity (VAS) was lower for pts pretreated with IBA (2.5 ± 2.1) compared to BP-naïve pts (3.2 ± 2.4; p &lt; 0.0001) or pts pretreated with other BPs (3.1 ± 2.4; p &lt; 0.0001) and analgesic use was less frequent (38% vs 47% and 44%, respectively). For the 2678 pts evaluable for renal function throughout the observation period, mean eCrCl at baseline was significantly lower in pts pretreated with ZOL (72.4 ± 31.7 ml/min) than in BP-naïve (79.5 ± 30.7 ml/min; P&lt;0.0001) or IBA-pretreated pts (77.8 ± 28.8 ml/min; p=0.0090). 64% of the total study population achieved a decrease in pain severity on IBA treatment. In pts reporting pain at baseline, mean pain severity decreased throughout the observation period (3.1 ± 2.4 to 2.3 ± 2; p &lt; 0.0001). In parallel, there was an overall reduction of analgesic use with 57% of pts not requiring analgesics at the last observation and more pts being switched to less potent or no analgesic treatment than patients requiring more analgesia. SRE were rare (7%), irrespective of prior treatment. Changes in renal function during IBA treatment were small and balanced across all subgroups; no severe renal adverse events were observed. Thirteen cases of osteonecrosis of the jaw were reported during the observation period, 8 of which had received ZOL as prior treatment. Overall tolerability of IBA treatment was rated as good or very good by 98% of physicians.
Conclusion: In this NIS in BC pts with MBD, the largest-to-date study with IBA, IV and oral IBA showed marked and sustained pain relief with an overall reduction of analgesic use and a renal safety profile comparable to results of RCT.
Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-13-02.