Introduction: Improvements are needed in the management of cancer-induced bone pain (CIBP). The objective of this study was to assess the efficacy and safety of pregabalin compared with placebo in the adjunctive treatment of patients with moderate to severe CIBP who were receiving opioids.
Methods: In this randomized, double-blind, placebo-controlled, parallel-group, multicenter trial, 152 adults diagnosed with a malignant, solid tumor with metastases to bone were randomized to flexible-dose pregabalin (100, 150, 300, or 600 mg/day) or placebo, as add-on to stable opioid analgesic therapy, which was optimized prior to the start of the study. The primary efficacy endpoint was the duration-adjusted average change (DAAC) from baseline in the daily worst pain at the reference site (measured by 11-point numeric rating scale [NRS]) during the fixed-dosage phase. The study was terminated early following an interim analysis that indicated an increase in sample size would be needed to satisfy statistical assumptions for the primary endpoint. Given the early termination of the study, only descriptive analyses were performed.
Results: The mean (standard deviation) DAAC from baseline in NRS score for the primary endpoint favored pregabalin treatment: -1.53 (1.81) in the pregabalin group and -1.23 (1.74) in the placebo group. Mean DAAC for average pain and sleep interference (NRS) also favored pregabalin. More patients treated with pregabalin reported improvement ("very much improved," "much improved," or "minimally improved") based on Patient Global Impression of Change: 81.4% compared with 70.0% in the placebo group.
Conclusion: Data from this study indicate that pregabalin use may reduce metastatic bone pain. Due to the incomplete analysis, further study of pregabalin in the management of CIBP is required.
Trial registration: ClinicalTrials.gov NCT00381095.