A Phase II trial evaluating the palliative benefit of second-line oral ibandronate in breast cancer patients with either a skeletal related event (SRE) or progressive bone metastases (BM) despite standard bisphosphonate (BP) therapy.

BACKGROUND: Despite bisphosphonate treatment, most patients with metastatic breast cancer will have either progressive bone metastases or skeletal related events (SREs). We evaluated the impact of second-line ibandronate on pain control and markers of bone turnover in these patients.

METHODS: Patients with either an SRE or bony progression while on clodronate or intravenous (IV) pamidronate were switched to oral ibandronate 50 mg daily for 12 weeks. Pain scores and urinary N-telopeptide were evaluated weekly for 4 weeks and at weeks 8 and 12. There was no change in systemic anti-cancer treatment in the month before or after commencing study treatment. Palliative response was defined as a > or = two-unit reduction in the worst pain score. Patient preferences between IV and oral bisphosphonate therapy were assessed.

RESULTS: Thirty women completed the study. By week 12, patients experienced a significant improvement in pain control (OR = 0.41; P = 0.028) with 12 of 26 (46.2%) evaluable patients achieving a palliative response. Of the 23 patients who had received first-line IV pamidronate, 20 of 23 (87.0%) preferred oral therapy.

CONCLUSION: Patients with either progressive bone metastases or SREs while on clodronate or pamidronate may experience significant pain palliation with a switch to a more potent bisphosphonate. If confirmed by randomized trials, clinicians can start moving away from the paradigm whereby patients remain on a single bisphosphonate regimen throughout the course of their disease.