Objective: We recently reported the efficacy of rofecoxib in two randomized controlled trials in chronic low back pain (CLBP). The objectives of this report are to present data regarding the onset of efficacy of rofecoxib from these trials and propose methods for reporting onset.
Research design and methods: Patients were aged 18-75, with non-radicular CLBP for >or= 3 months. Patients were randomized to rofecoxib 25mg, 50 mg, or placebo once daily for 4 weeks. Assessments included Low Back Pain and Bothersomeness scales every morning and Relief from Starting Pain after the first dose at 0.5, 1, 2, 3, 4 h, bedtime, and next morning. Onset of meaningful relief was measured by Time to Confirmed 50% Reduction in Pain and Time to Confirmed 'Slightly' or 'Not At All' Bothersome Pain. Onset of perceptible pain relief was measured by Time to At Least 'A Little' Confirmed Pain Relief.
Results: 690 patients entered. Significantly more patients treated with rofecoxib had compared with 1/3 receiving placebo. Median meaningful relief compared to placebo: 60.4, 58.4, and 34.7% for rofecoxib 25mg, 50 mg, and placebo (p< 0.001). Median time to meaningful relief for rofecoxib was 2 days, 1 day sooner than placebo. Rofecoxib was superior to placebo by bedtime after the first dose.
Conclusions: Approximately 2/3 of patients achieved meaningful pain relief with rofecoxib time to onset of meaningful relief was about 2 days, but superior relief over placebo was seen by bedtime after the first dose. Onset of perceptible pain relief was within 2 h. We propose that measures of onset of analgesic effect include the proportion of patients who achieve meaningful pain relief and in this subgroup, the time-to-onset of confirmed meaningful reduction in pain intensity, time-to-onset of confirmed pain relief, and time to first separation from placebo in the proportion of patients who achieve meaningful pain relief.