Research design considerations for chronic pain prevention clinical trials: IMMPACT recommendations.

Although certain risk factors can identify individuals who are most likely to develop chronic pain, few interventions to prevent chronic pain have been identified. To facilitate the identification of preventive interventions, an IMMPACT meeting was convened to discuss research design considerations for clinical trials investigating the prevention of chronic pain. We present general design considerations for prevention trials in populations that are at relatively high risk for developing chronic pain. Specific design considerations included subject identification, timing and duration of treatment, outcomes, timing of assessment, and adjusting for risk factors in the analyses. We provide a detailed examination of 4 models of chronic pain prevention (ie, chronic postsurgical pain, postherpetic neuralgia, chronic low back pain, and painful chemotherapy-induced peripheral neuropathy). The issues discussed can, in many instances, be extrapolated to other chronic pain conditions. These examples were selected because they are representative models of primary and secondary prevention, reflect persistent pain resulting from multiple insults (ie, surgery, viral infection, injury, and toxic or noxious element exposure), and are chronically painful conditions that are treated with a range of interventions. Improvements in the design of chronic pain prevention trials could improve assay sensitivity and thus accelerate the identification of efficacious interventions. Such interventions would have the potential to reduce the prevalence of chronic pain in the population. Additionally, standardization of outcomes in prevention clinical trials will facilitate meta-analyses and systematic reviews and improve detection of preventive strategies emerging from clinical trials.

Research design considerations for chronic pain prevention clinical trials: IMMPACT recommendations.

Although certain risk factors can identify individuals who are most likely to develop chronic pain, few interventions to prevent chronic pain have been identified. To facilitate the identification of preventive interventions, an IMMPACT meeting was convened to discuss research design considerations for clinical trials investigating the prevention of chronic pain. We present general design considerations for prevention trials in populations that are at relatively high risk for developing chronic pain. Specific design considerations included subject identification, timing and duration of treatment, outcomes, timing of assessment, and adjusting for risk factors in the analyses. We provide a detailed examination of 4 models of chronic pain prevention (ie, chronic postsurgical pain, postherpetic neuralgia, chronic low back pain, and painful chemotherapy-induced peripheral neuropathy). The issues discussed can, in many instances, be extrapolated to other chronic pain conditions. These examples were selected because they are representative models of primary and secondary prevention, reflect persistent pain resulting from multiple insults (ie, surgery, viral infection, injury, and toxic or noxious element exposure), and are chronically painful conditions that are treated with a range of interventions. Improvements in the design of chronic pain prevention trials could improve assay sensitivity and thus accelerate the identification of efficacious interventions. Such interventions would have the potential to reduce the prevalence of chronic pain in the population. Additionally, standardization of outcomes in prevention clinical trials will facilitate meta-analyses and systematic reviews and improve detection of preventive strategies emerging from clinical trials.

A randomized, double-blind, placebo-controlled phase 3 study of the relative efficacy and tolerability of tapentadol IR and oxycodone IR for acute pain.

OBJECTIVE: To evaluate the relative efficacy and tolerability of tapentadol immediate release (IR) and oxycodone IR for management of moderate to severe pain following orthopedic surgery (bunionectomy). METHODS: Randomized patients (N = 901) received oral tapentadol IR 50 or 75 mg, oxycodone HCl IR 10 mg, or placebo every 4-6 h over a 72-h period following surgery. Acetaminophen (< or =2 g) was allowed in the first 12 h after the first dose of study drug. In the primary analysis, tapentadol IR (50 and 75 mg) was evaluated for efficacy superior to placebo and non-inferior to oxycodone HCl IR 10 mg (using sum of pain intensity difference [SPID] over 48 h), and tolerability superior to oxycodone IR (using incidence of treatment-emergent adverse events [TEAEs] of nausea and/or vomiting). RESULTS: Statistically significantly higher mean SPID(48) values were observed with tapentadol IR (50 and 75 mg) and oxycodone HCl IR 10 mg than placebo (all p < 0.001). The efficacy of tapentadol IR 50 mg and 75 mg was non-inferior to oxycodone HCl IR 10 mg. The incidence of TEAEs of nausea and/or vomiting was statistically significantly lower with tapentadol IR 50 mg versus oxycodone IR 10 mg (35 vs. 59%; p < 0.001). No statistically significant difference in the incidence of nausea and/or vomiting was observed between tapentadol IR 75 mg and oxycodone IR 10 mg (51 vs. 59%; p = 0.057). A possible limitation of this study was that the intense dose and patient monitoring may not represent real-world situations and may result in higher incidences of TEAEs than expected in a practice setting; this bias would be similar for all treatment groups. CONCLUSIONS: Clinically meaningful and statistically significant improvements were observed with tapentadol IR 50 mg and 75 mg compared with placebo for the relief of moderate-to-severe acute pain after orthopedic surgery. Tapentadol IR 50 mg and 75 mg were non-inferior to oxycodone HCl IR 10 mg for the treatment of acute pain based on the primary efficacy endpoint of SPID(48) and the pre-specified margin of 48 points. The incidence of nausea and/or vomiting was statistically significantly lower for tapentadol IR 50 mg and numerically lower for tapentadol IR 75 mg than for oxycodone HCl IR 10 mg.