Study 06CCL3-001 was a multi-centre, randomized, double-blind, parallel-arm study that compared the efficacy and safety of Labopharm’s twice-daily tramadol-acetaminophen formulation to placebo in the treatment of moderate to severe acute low back pain. A total of 277 patients were included in the study. Approximately 13% of patients in the active treatment group discontinued early and 5% of patients in the placebo group discontinued early.
According to Labopharm, results of the efficacy measures in the study demonstrated a statistically significant difference from placebo in some cases but not in others. An analysis of covariance demonstrated a statistically significant difference from placebo on the sum of pain intensity differences (SPID) over 50 hours using last observation carried-forward (LOCF) as the imputation method, however, the results were not statistically significant using LOCF/BOCF (baseline observation carried-forward), the primary endpoint.
A non-parametric analysis, however, demonstrated statistical significance using both LOCF and LOCF/BOCF as imputation methods. The difference from placebo on the total pain relief score was also statistically significant using both LOCF and LOCF/BOCF imputation methods and the patients’ global impression of the effectiveness of the study medication was statistically different from placebo, the company said.
Labopharm believes that it is likely that the results of this trial are insufficient to support the acceptance of a new drug application by the FDA in the US.