Efficacy and safety of duloxetine in Chinese patients with chronic pain due to osteoarthritis: a randomized, double-blind, placebo-controlled study

OBJECTIVE

We assessed the efficacy and safety of duloxetine (60 mg, once daily), compared with placebo, during a 13-week treatment period in Chinese patients with chronic pain due to osteoarthritis (OA).

DESIGN

Patients were at least 40 years old (male or female) who met American College of Rheumatology clinical and radiographic criteria for the diagnosis of OA of the knee or hip. The primary efficacy measure in this phase 3, randomized, double-blind, placebo-controlled clinical trial was assessment of pain severity by the Brief Pain Inventory (BPI) 24-h Average Pain rating. The clinical trial was conducted at 17 study centers. Statistical approaches included mixed-effects model repeated measures and analysis of covariance. A Fisher exact test was applied to categorical variables.

RESULTS

Of 407 patients randomized (duloxetine: N = 205; placebo: N = 202), 166 (81.0%) patients from the duloxetine group and 176 (87.1%) patients from the placebo group completed the 13-week treatment phase. The majority (76.4%) of patients was female; mean age was 60.5 years. Duloxetine-treated patients reported significant pain reduction, compared with placebo treatment, on the BPI 24-h Average Pain rating (least-squares mean (LS Mean) change from baseline to endpoint [95% confidence interval (CI)], duloxetine: -2.23; placebo: -1.73; difference = -0.50 [-0.80, -0.20]; P = 0.001). The incidence of discontinuations due to adverse events was 9.0% in duloxetine-treated patients and 4.5% in placebo-treated patients (P = 0.109).

CONCLUSIONS

This study demonstrated the efficacy of duloxetine in Chinese patients with chronic pain due to OA. The safety profile of duloxetine observed in this study was consistent with that in previous duloxetine trials. This trial is registered with ClinicalTrials.gov (NCT01931475).

Treatment of patients with diabetic peripheral neuropathic pain in China: a double-blind randomised trial of duloxetine vs. placebo

BACKGROUND

Duloxetine has been approved in the United States, European Union and some Asian countries for the treatment of diabetic peripheral neuropathic pain (DPNP). We assessed the efficacy and safety of duloxetine (60 mg once daily) compared with placebo in Chinese patients suffering from DPNP.

METHODS

This was a phase 3, multicenter, randomised, double-blind, parallel, placebo-controlled, 12-week trial of the treatment of DPNP with duloxetine. Subjects were male and female outpatients ≥ 18 years of age with DPNP, as assessed by the Michigan Neuropathy Screening Instrument, and had a rating of ≥ 4 on the Brief Pain Inventory-Modified Short Form-Severity weekly average pain item. The primary efficacy measure was the reduction in pain severity from baseline to 12 weeks, as measured by the weekly mean of 24-h average pain ratings recorded in the patient's diary. Mean changes from baseline in efficacy measures were analysed by a restricted maximum likelihood-based, mixed-effects model repeated measures approach and by analysis of covariance.

RESULTS

Of the 405 patients randomised, 203 patients were assigned to duloxetine 60 mg once daily and 202 patients were assigned to placebo. Duloxetine-treated patients showed significantly greater pain relief on 24-h average pain ratings compared with placebo-treated patients each week of the 12-week study period [week 12: least squares (LS) mean change duloxetine: -2.40, placebo: -1.97; LS mean change difference (95% confidence interval) = -0.43 (-0.82, -0.04), p = 0.030]. Compared with placebo, patients treated with duloxetine experienced higher rates of nausea (p = 0.010), somnolence (p < 0.001) and asthenia (p = 0.002).

CONCLUSIONS

Duloxetine-treated patients showed significantly greater pain relief compared with placebo-treated patients over the 12-week study period. Duloxetine was shown in Chinese patients to have a safety profile similar to that found in previous duloxetine trials.