Donald C. Manning

Core outcome domains for chronic pain clinical trials: IMMPACT recommendations

AbstractObjective. To provide recommendations for the core outcome domains that should be considered by investigators conducting clinical trials of the efficacy and effectiveness of treatments for chronic pain. Development of a core set of outcome domains would facilitate comparison and pooling of d

Core outcome domains for chronic pain clinical trials

&NA; Objective. To provide recommendations for the core outcome domains that should be considered by investigators conducting clinical trials of the efficacy and effectiveness of treatments for chronic pain. Development of a core set of outcome domains would facilitate comparison and pooling of data, encourage more complete reporting of outcomes, simplify the preparation and review of research proposals and manuscripts, and allow clinicians to make informed decisions regarding the risks and benefits of treatment. Methods. Under the auspices of the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT), 27 specialists from academia, governmental agencies, and the pharmaceutical industry participated in a consensus meeting and identified core outcome domains that should be considered in clinical trials of treatments for chronic pain. Conclusions. There was a consensus that chronic pain clinical trials should assess outcomes representing six core domains: (1) pain, (2) physical functioning, (3) emotional functioning, (4) participant ratings of improvement and satisfaction with treatment, (5) symptoms and adverse events, (6) participant disposition (e.g. adherence to the treatment regimen and reasons for premature withdrawal from the trial). Although consideration should be given to the assessment of each of these domains, there may be exceptions to the general recommendation to include all of these domains in chronic pain trials. When this occurs, the rationale for not including domains should be provided. It is not the intention of these recommendations that assessment of the core domains should be considered a requirement for approval of product applications by regulatory agencies or that a treatment must demonstrate statistically significant effects for all of the relevant core domains to establish evidence of its efficacy.

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

&NA; There has been an increase in the number of chronic pain clinical trials in which the treatments being evaluated did not differ significantly from placebo in the primary efficacy analyses despite previous research suggesting that efficacy could be expected. These findings could reflect a true lack of efficacy or methodological and other aspects of these trials that compromise the demonstration of efficacy. There is substantial variability among chronic pain clinical trials with respect to important research design considerations, and identifying and addressing any methodological weaknesses would enhance the likelihood of demonstrating the analgesic effects of new interventions. An IMMPACT consensus meeting was therefore convened to identify the critical research design considerations for confirmatory chronic pain trials and to make recommendations for their conduct. We present recommendations for the major components of confirmatory chronic pain clinical trials, including participant selection, trial phases and duration, treatment groups and dosing regimens, and types of trials. Increased attention to and research on the methodological aspects of confirmatory chronic pain clinical trials has the potential to enhance their assay sensitivity and ultimately provide more meaningful evaluations of treatments for chronic pain.

Developing patient-reported outcome measures for pain clinical trials : IMMPACT recommendations

a University of Washington, Seattle, WA 98195, USA b University of Rochester School of Medicine and Dentistry, Rochester, NY, USA c United States Food and Drug Administration, Rockville, MD, USA d Northwestern University, Chicago, IL, USA e Johnson and Johnson, Raritan, NY, USA f AstraZeneca, Wilmington, DE, USA g University of California San Diego, La Jolla, CA, USA h Merck and Company, Blue Bell, PA, USA i University of Texas, M.D. Anderson Cancer Center, USA j American Chronic Pain Association, Rocklin, CA, USA k Allergan, Inc, Irvine, CA, USA l National Institute of Dental and Craniofacial Research, Bethesda, MD, USA m University of Pennsylvania, Philadelphia, PA, USA n Johns Hopkins University, Baltimore, MD, USA o University Health Network and University of Toronto, Toronto, Canada p Novartis Pharmaceuticals, East Hanover, NJ, USA q VA Connecticut Healthcare System, West Haven, CT, USA r Yale University, New Haven, CT, USA s Celgene Corporation, Warren, NJ, USA t Pfizer Global Research and Development, Ann Arbor, MI, USA u Dalhousie University, Halifax, Nova Scotia, Canada v London Regional Cancer Centre, London, Ont., Canada

Critical evaluation of the streptozotocin model of painful diabetic neuropathy in the rat

Streptozotocin (STZ)-induced diabetes in the rat has been increasingly used as a model of painful diabetic neuropathy to assess the efficacies of potential analgesic agents. We have established this model, and here we question whether the changes in nocifensive reflex activity, used as a measure of hyperalgesia, are genuinely indicative of peripheral neuropathy or may rather be attributed to the extreme poor health of the animals. For comparison we have examined animals with peripheral neuropathy induced by partial ligation of the sciatic nerve. Diabetic animals were chronically ill, with reduced growth rate, polyuria, diarrhoea, and had enlarged and distended bladders. Indicative of their poor health, diabetic animals showed markedly reduced motor activity. In contrast, following partial sciatic nerve ligation rats showed none of these adverse effects and their motor activity was not different to naive animals. Diabetic animals displayed marked mechanical hyperalgesia, and some thermal hypoalgesia. Morphine and L-baclofen partially reversed established STZ-induced mechanical hyperalgesia, whilst the NK-1 receptor-antagonist RP-67580, the NMDA-antagonists MK801 and ketamine, and the nitric oxide synthase inhibitor L-NAME were without significant effect. Morphine and L-baclofen produced greater reversal of mechanical hyperalgesia following partial nerve ligation, although RP67580 and MK801 showed little or no activity. These data confirm previous findings that STZ-induced diabetes in rats produces long-lasting mechanical, but not thermal hyperalgesia. In our experience this mechanical hyperalgesia is largely resistant to a range of pharmacological tools. However, we feel that the profound ill-health of the animals, together with the poor activity of a range of potential analgesic drugs, must raise questions on the predictive value of these animals as a model for the human condition of chronic diabetic pain seen in patients receiving long-term insulin treatment, as well as ethical concerns on the use of the animals themselves.

Analyzing multiple endpoints in clinical trials of pain treatments: IMMPACT recommendations

Abstract The increasing complexity of randomized clinical trials and the practice of obtaining a wide variety of measurements from study participants have made the consideration of multiple endpoints a critically important issue in the design, analysis, and interpretation of clinical trials. Failure to consider important outcomes can limit the validity and utility of clinical trials; specifying multiple endpoints for the evaluation of treatment efficacy, however, can increase the rate of false positive conclusions about the efficacy of a treatment. We describe the use of multiple endpoints in the design, analysis, and interpretation of pain clinical trials, and review available strategies and methods for addressing multiplicity. To decrease the probability of a Type I error (i.e., the likelihood of obtaining statistically significant results by chance) in pain clinical trials, the use of gatekeeping procedures and other methods that correct for multiple analyses is recommended when a single primary endpoint does not adequately reflect the overall benefits of treatment. We emphasize the importance of specifying in advance the outcomes and clinical decision rule that will serve as the basis for determining that a treatment is efficacious and the methods that will be used to control the overall Type I error rate.

Efficacy of Dexmethylphenidate for the Treatment of Fatigue After Cancer Chemotherapy: A Randomized Clinical Trial

Cancer and its treatment can induce subjective and objective evidence of diminished functional capacity encompassing physical fatigue and cognitive impairment. Dexmethylphenidate (D-MPH; the D-isomer of methylphenidate) was evaluated for treatment of chemotherapy-related fatigue and cognitive impairment. A randomized, double-blind, placebo-controlled, parallel-group study evaluated the potential therapeutic effect and safety of D-MPH in the treatment of patients with chemotherapy-related fatigue. Change from baseline in the Functional Assessment of Chronic Illness Therapy-Fatigue Subscale (FACIT-F) total score at Week 8 was the primary outcome measure. One hundred fifty-four patients (predominantly with breast and ovarian cancers) were randomized and treated. Compared with placebo, D-MPH-treated subjects demonstrated a significant improvement in fatigue symptoms at Week 8 in the FACIT-F (P=0.02) and the Clinical Global Impression-Severity scores (P=0.02), without clinically relevant changes in hemoglobin levels. Cognitive function was not significantly improved. There was a higher rate of study drug-related adverse events (AEs) (48 of 76 [63%] vs. 22 of 78 [28%]) and a higher discontinuation rate because of AEs (8 of 76 [11%] vs. 1 of 78 [1.3%]) in D-MPH-treated subjects compared with placebo-treated subjects. The most commonly reported AEs independent of study drug relationship in D-MPH-treated subjects were headache, nausea, and dry mouth, and in placebo-treated subjects were headache, diarrhea, and insomnia. D-MPH produced significant improvement in fatigue in subjects previously treated with cytotoxic chemotherapy. Further studies with D-MPH or other agents to explore treatment response in chemotherapy-associated fatigue should be considered.

ASCPRO Recommendations for the Assessment of Fatigue as an Outcome in Clinical Trials

CONTEXT Development of pharmacological and behavioral interventions for cancer-related fatigue (CRF) requires adequate measures of this symptom. A guidance document from the Food and Drug Administration offers criteria for the formulation and evaluation of patient-reported outcome measures used in clinical trials to support drug or device labeling claims. METHODS An independent working group, ASCPRO (Assessing Symptoms of Cancer Using Patient-Reported Outcomes), has begun developing recommendations for the measurement of symptoms in oncology clinical trials. The recommendations of the Fatigue Task Force for measurement of CRF are presented here. RESULTS There was consensus that CRF could be measured effectively in clinical trials as the sensation of fatigue or tiredness, impact of fatigue/tiredness on usual functioning, or as both sensation and impact. The ASCPRO Fatigue Task Force constructed a definition and conceptual model to guide the measurement of CRF. ASCPRO recommendations do not endorse a specific fatigue measure but clarify how to evaluate and implement fatigue assessments in clinical studies. The selection of a CRF measure should be tailored to the goals of the research. Measurement issues related to various research environments were also discussed. CONCLUSIONS There exist in the literature good measures of CRF for clinical trials, with strong evidence of clarity and comprehensibility to patients, content and construct validity, reliability, and sensitivity to change in conditions in which one would expect them to change (assay sensitivity), and sufficient evidence to establish guides for interpreting changes in scores. Direction for future research is discussed.

Analyzing multiple endpoints in clinical trials of pain treatments: IMMPACT recommendations. Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials.

Abstract The increasing complexity of randomized clinical trials and the practice of obtaining a wide variety of measurements from study participants have made the consideration of multiple endpoints a critically important issue in the design, analysis, and interpretation of clinical trials. Failure to consider important outcomes can limit the validity and utility of clinical trials; specifying multiple endpoints for the evaluation of treatment efficacy, however, can increase the rate of false positive conclusions about the efficacy of a treatment. We describe the use of multiple endpoints in the design, analysis, and interpretation of pain clinical trials, and review available strategies and methods for addressing multiplicity. To decrease the probability of a Type I error (i.e., the likelihood of obtaining statistically significant results by chance) in pain clinical trials, the use of gatekeeping procedures and other methods that correct for multiple analyses is recommended when a single primary endpoint does not adequately reflect the overall benefits of treatment. We emphasize the importance of specifying in advance the outcomes and clinical decision rule that will serve as the basis for determining that a treatment is efficacious and the methods that will be used to control the overall Type I error rate.

Single intrathecal administration of the transcription factor decoy AYX1 prevents acute and chronic pain after incisional, inflammatory, or neuropathic injury

Summary AYX1 is a DNA decoy designed to specifically inhibit, in the spinal cord and dorsal root ganglia network, the trauma‐induced transcription factor EGR1 responsible for long‐term neuronal hyper‐excitability. A single intrathecal administration of AYX1 around the time of surgery or trauma prevents acute and chronic pain in animal models of inflammatory, incisional, bone, and neuropathic pain. ABSTRACT The persistence of pain after surgery increases the recovery interval from surgery to a normal quality of life. AYX1 is a DNA‐decoy drug candidate designed to prevent post‐surgical pain following a single intrathecal injection. Tissue injury causes a transient activation of the transcription factor EGR1 in the dorsal root ganglia–dorsal horn network, which then triggers changes in gene expression that induce neuronal hypersensitivity. AYX1 is a potent, specific inhibitor of EGR1 activity that mimics the genomic EGR1‐binding sequence. Administered in the peri‐operative period, AYX1 dose dependently prevents mechanical hypersensitivity in models of acute incisional (plantar), inflammatory (CFA), and chronic neuropathic pain (SNI) in rats. Furthermore, in a knee surgery model evaluating functional measures of postoperative pain, AYX1 improved weight‐bearing incapacitance and spontaneous rearing compared to control. These data illustrate the potential clinical therapeutic benefits of AYX1 for preventing the transition of acute to chronic post‐surgical pain.