Search

Chronic pain clinical trials have historically assessed benefit and risk outcomes separately. However, a growing body of research suggests that a composite metric that accounts for benefit and risk in relation to each other can provide valuable insights into the effects of different treatments. Researchers and regulators have developed a variety of benefit-risk composite metrics, although the extent to which these methods apply to randomized clinical trials (RCTs) of chronic pain has not been evaluated in the published literature. This article was motivated by an Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials consensus meeting and is based on the expert opinion of those who attended. In addition, a review of the benefit-risk assessment tools used in published chronic pain RCTs or highlighted by key professional organizations (ie, Cochrane, European Medicines Agency, Outcome Measures in Rheumatology, and U.S. Food and Drug Administration) was completed. Overall, the review found that benefit-risk metrics are not commonly used in RCTs of chronic pain despite the availability of published methods. A primary recommendation is that composite metrics of benefit-risk should be combined at the level of the individual patient, when possible, in addition to the benefit-risk assessment at the treatment group level. Both levels of analysis (individual and group) can provide valuable insights into the relationship between benefits and risks associated with specific treatments across different patient subpopulations. The systematic assessment of benefit-risk in clinical trials has the potential to enhance the clinical meaningfulness of RCT results.

Variability in pain-related outcomes can hamper assay sensitivity of chronic pain clinical trials. Expectations of outcome in such trials may account for some of this variability, and thereby impede development of novel pain treatments. Measurement of participants' expectations prior to initiating study treatment (active or placebo) is infrequent, variable, and often unvalidated. Efforts to optimize and standardize measurement, analysis, and management of expectations are needed. In this Focus Article, we provide an overview of research findings on the relationship between baseline expectations and pain-related outcomes in clinical trials of pharmacological and nonpharmacological pain treatments. We highlight the potential benefit of adjusting for participants' expectations in clinical trial analyses and draw on findings from patient interviews to discuss critical issues related to measurement of expectations. We conclude with suggestions regarding future studies focused on better understanding the utility of incorporating these measures into clinical trial analyses. PERSPECTIVE: This focus article provides an overview of the relationship between participants' baseline expectations and pain-related outcomes in the setting of clinical trials of chronic pain treatments. Systematic research focused on the measurement of expectations and the impact of adjusting for expectations in clinical trial analyses may improve assay sensitivity.

Supplemental Digital Content is Available in the Text., Opioids relieve acute pain, but there is little evidence to support the stability of the benefit over long-term treatment of chronic noncancer pain. Previous systematic reviews consider only group level published data which did not provide adequate detail. Our goal was to use patient-level data to explore the stability of pain, opioid dose, and either physical function or pain interference in patients treated for 12 months with abuse deterrent formulations of oxycodone and hydrocodone. All available studies in the Food and Drug Administration Document Archiving, Reporting, and Regulatory Tracking System were included. Patient-level demographics, baseline data, exposure, and outcomes were harmonized. Individual patient slopes were calculated from a linear model of pain, physical function, and pain interference to determine response over time. Opioid dose was summarized by change between baseline and the final month of observation. Patients with stable or less pain, stable or lower opioid dose, and stable or better physical function (where available) met our prespecified criteria for maintaining long-term benefit from chronic opioids. Of the complete data set of 3192 patients, 1422 (44.5%) maintained their pain level and opioid dose. In a secondary analysis of 985 patients with a measured physical function, 338 (34.3%) maintained their physical function in addition to pain and opioid dose. Of 2040 patients with pain interference measured, 788 (38.6%) met criteria in addition. In a carefully controlled environment, about one-third of patients successfully titrated on opioids to treat chronic noncancer pain demonstrated continued benefit for up to 12 months.

This systematic review assessed design characteristics and reporting quality of published randomized clinical trials of spinal cord stimulation (SCS) for treatment of pain in adults and adolescents. The study protocol was registered with PROSPERO (CRD42018090412). Relevant articles were identified by searching the following databases through December 31, 2018: MEDLINE, Embase, WikiStim, The Cochrane Database of Systematic Reviews, and The Cochrane Central Register of Controlled Trials. Forty-six studies were included. Eighty-seven percent of articles identified a pain-related primary outcome. Secondary outcomes included physical functioning, health-related quality of life, and reductions in opioid use. Nineteen of the 46 studies prespecified adverse events as an outcome, with 4 assessing them as a primary outcome. Eleven studies stated that they blinded participants. Of these, only 5 were assessed as being adequately blinded. The number of participants enrolled was generally low (median 38) and study durations were short (median 12 weeks), particularly in studies of angina. Fifteen studies employed an intention-to-treat analysis, of which only seven specified a method to accommodate missing data. Review of these studies identified deficiencies in both reporting and methodology. The review's findings suggest areas for improving the design of future studies and increasing transparency of reporting. Perspective This article presents a systematic review of research methods and reporting quality of randomized clinical trials of SCS for the treatment of various pain complaints. The review identifies deficiencies in both methodology and reporting, which may inform the design of future studies and improve reporting standards.

Supplemental Digital Content is Available in the Text., Spinal cord stimulation (SCS) is an interventional nonpharmacologic treatment used for chronic pain and other indications. Methods for evaluating the safety and efficacy of SCS have evolved from uncontrolled and retrospective studies to prospective randomized controlled trials (RCTs). Although randomization overcomes certain types of bias, additional challenges to the validity of RCTs of SCS include blinding, choice of control groups, nonspecific effects of treatment variables (eg, paresthesia, device programming and recharging, psychological support, and rehabilitative techniques), and safety considerations. To address these challenges, 3 professional societies (Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials, Institute of Neuromodulation, and International Neuromodulation Society) convened a meeting to develop consensus recommendations on the design, conduct, analysis, and interpretation of RCTs of SCS for chronic pain. This article summarizes the results of this meeting. Highlights of our recommendations include disclosing all funding source and potential conflicts; incorporating mechanistic objectives when possible; avoiding noninferiority designs without internal demonstration of assay sensitivity; achieving and documenting double-blinding whenever possible; documenting investigator and site experience; keeping all information provided to patients balanced with respect to expectation of benefit; disclosing all information provided to patients, including verbal scripts; using placebo/sham controls when possible; capturing a complete set of outcome assessments; accounting for ancillary pharmacologic and nonpharmacologic treatments in a clear manner; providing a complete description of intended and actual programming interactions; making a prospective ascertainment of SCS-specific safety outcomes; training patients and researchers on appropriate expectations, outcome assessments, and other key aspects of study performance; and providing transparent and complete reporting of results according to applicable reporting guidelines.

OBJECTIVES In this study, patients with painful diabetic neuropathy were trained using an experimental pain paradigm in an attempt to enroll a subset of patients who are "pain connoisseurs" and therefore more able to discriminate between active and placebo treatments. METHODS AZD5213, a novel histamine H3 receptor inverse agonist+pregabalin, pregabalin, and placebo were then tested in a 3-period cross-over. RESULTS The study did not provide any evidence of clinical efficacy for AZD5213 when combined with pregabalin in the treatment of painful diabetic neuropathy. DISCUSSION The training of study patients in pain reporting and subsequent enrichment with good pain reporters also did not enable the robust detection of the efficacy of pregabalin relative to placebo in a small sample size. Further work is required before recommending the use of "connoisseur" patients in future neuropathic pain studies.

The estimated probability of progressing from phase 3 analgesic clinical trials to regulatory approval is approximately 57%, suggesting that a considerable number of treatments with phase 2 trial results deemed sufficiently successful to progress to phase 3 do not yield positive phase 3 results. Deficiencies in the quality of clinical trial conduct could account for some of this failure. An Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials meeting was convened to identify potential areas for improvement in trial conduct in order to improve assay sensitivity (ie, ability of trials to detect a true treatment effect). We present recommendations based on presentations and discussions at the meeting, literature reviews, and iterative revisions of this article. The recommendations relate to the following areas: 1) study design (ie, to promote feasibility), 2) site selection and staff training, 3) participant selection and training, 4) treatment adherence, 5) data collection, and 6) data and study monitoring. Implementation of these recommendations may improve the quality of clinical trial data and thus the validity and assay sensitivity of clinical trials. Future research regarding the effects of these strategies will help identify the most efficient use of resources for conducting high quality clinical trials. PERSPECTIVE: Every effort should be made to optimize the quality of clinical trial data. This manuscript discusses considerations to improve conduct of pain clinical trials based on research in multiple medical fields and the expert consensus of pain researchers and stakeholders from academia, regulatory agencies, and industry.

Objective A literature review was conducted to compare placebo responses in a recent trial-which implemented an accurate pain reporting (APR) and placebo response reduction (PRR) training program-with placebo responses in similar previous trials in chronic lower back pain (CLBP) that did not use such training. Methods A literature search was performed to find parallel design, randomized, controlled trials of pharmacological treatments administered orally or through intravenous injection for CLBP. Studies were assessed for the proportion of placebo responders, defined as the proportion of patients in the placebo group with ≥30% reduction in pain intensity. A χ analysis was performed on the proportion of responders from the SPRINT trial and from other similar studies. Results Of 844 studies identified in the initial screening process, 16 studies were included for comparison. The percentage of placebo responders was statistically significantly lower in the SPRINT study (19.1%) compared with other CLBP trials (38.0%) (P=0.003). Our results show that the placebo response was lower in the SPRINT trial than other comparable studies on CLBP. Discussion These findings are consistent with results from other studies showing that neutralizing subject and study staff expectations of therapeutic benefit can decrease the placebo response in clinical trials. The results of this study suggest training participants and staff to improve pain reporting accuracy, neutralize expectations, and decrease external cues that may bias participants' pain ratings in clinical trials may effectively decrease the placebo response leading to increased assay sensitivity.

ObjectiveTo evaluate the SUMMIT-07 trial opioid withdrawal results of NKTR-181 (oxycodegol), a new molecular entity mu-opioid receptor agonist.DesignPhase 3, enriched-enrollment, double-blind, randomized-withdrawal study in patients with chronic low back pain (CLBP).SettingConducted in the United States at multiple sites.MethodsSUMMIT-07 was comprised of five periods: screening; NKTR-181 open-label titration (100 to 400 mg twice daily); 12-week randomized, double-blind study drug (NKTR-181 or placebo); one-week study drug taper; and two-week safety follow-up. Permitted rescue medication included hydrocodone 5 mg/acetaminophen 300 mg (two tablets daily) for two weeks after randomization, then acetaminophen 1.0 gm daily for the remainder of the trial. Signs and symptoms of drug withdrawal were evaluated using the Clinical Opiate Withdrawal Scale (COWS); Subjective Opiate Withdrawal Scale (SOWS); Misuse, Abuse, and Diversion Drug Event Reporting System (MADDERS); and withdrawal-related adverse events.ResultsOf 1,190 patients entering titration, one patient had moderate withdrawal (COWS score 13/48 maximum) three days after discontinuing NKTR-181. Of 610 patients randomized (N = 309, NKTR-181; N = 301, placebo), no COWS scores indicating withdrawal at a moderate level or greater (i.e., score ≥13) were observed at any time point. At day 8 after randomization, week 12, and the end of tapering, COWS scores indicating mild withdrawal (ConclusionsNKTR-181 exhibited a low rate and severity of opioid withdrawal in SUMMIT-07 patients with CLBP.

A phase 3 randomized controlled study comparing triamcinolone acetonide extended-release (TA-ER) to conventional TA crystalline suspension (TAcs) reported variable efficacy results. Enrollment criteria may have contributed to this discrepancy, as moderate-to-severe average daily pain (ADP) was required at baseline, whereas no limitations were placed on Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC-A) pain severity. We conducted a post hoc sensitivity analysis to compare treatment effects in patients reporting moderate-to-severe osteoarthritis (OA) pain on both scales.Participants 40 years old with symptomatic knee OA were randomly assigned to a single intra-articular injection of TA-ER 32 mg, TAcs 40 mg, or saline-placebo and followed for 24 weeks. Patient-reported ADP, WOMAC-A, rescue medication usage, and adverse events (AEs) were assessed. Participants who reported moderate-to-severe OA pain at baseline using both instruments (ADP ≥ 5 to ≤ 9, maximum 10 and WOMAC-A ≥ 2, maximum 4) were categorized as "concordant" pain reporters; patients with baseline moderate-to-severe OA on ADP only were termed "discordant" pain reporters.Two-hundred-ninety-two concordant pain reporters of 484 total subjects received TA-ER 32 mg (n = 95), TAcs 40 mg (n = 100), or saline-placebo (n = 97). Baseline characteristics and AE profiles of the concordant and discordant pain responders were consistent with the full analysis population. Among concordant pain reporters, TA-ER significantly (p 0.05) improved ADP scores vs. TAcs (weeks 5-19; area-under-the-effect [AUE]In patients reporting moderate-to-severe knee OA pain at baseline based on concordant ADP and WOMAC-A scores, TA-ER provided statistically significant pain relief for ≥ 12 weeks compared with conventional TAcs.ClinicalTrials.gov Identifier: NCT02357459.Osteoarthritis is a chronic condition that greatly impacts patients. Pain is the most common symptom of osteoarthritis. Clinical trials evaluating the effects of new drugs to treat osteoarthritis pain frequently use scales to rate overall pain following treatment. Patients may rate their pain using a number that best describes their pain, with the lowest number typically meaning “no pain,” and the highest number typically meaning “pain as bad as you can imagine.” Other rating scales may be used to rate pain in situations commonly associated with osteoarthritis.Results from a large clinical trial demonstrated that injection of an extended-release steroid significantly reduced pain compared with a conventional steroid injection on only one of the two pain-reporting scales used in the trial. A closer look found that some patients reported their pain differently on the two rating scales at the start of the trial, with some reporting moderate-to-severe pain using one questionnaire and mild pain using the other. Here, we focused on those patients who reported having moderate-to-severe osteoarthritis knee pain on both pain scales at the start and found that the pain relief benefit associated with the extended-release steroid injection was greatly improved compared with the conventional steroid injection with both measures. Patients receiving the extended-release steroid injection also decreased their use of rescue medication for pain relief.

Diana S Meske,1 Ben J Vaughn,2 Ernest A Kopecky,3 Nathaniel Katz4,5 1Collegium Pharmaceutical, Inc, Stoughton, MA, USA; 2Rho, Chapel Hill, NC, USA; 3Teva Branded Pharmaceutical Products R&D, Inc, Frazer, PA, USA; 4WCG Analgesic Solutions, Wayland, MA, USA; 5Department of Anesthesia, Tufts University School of Medicine, Boston, MA, USACorrespondence: Diana S MeskeCollegium Pharmaceutical, Inc, Stoughton, MA, USATel +1 517 712 3087Email dsmeske@gmail.comBackground: Many aspects of study conduct impact the observed effect size of treatment. Data were utilized from a recently published meta-analysis of randomized, double-blind, placebo-controlled, clinical trials performed for the United States Food and Drug Administration (FDA) approval of full mu-agonist opioids for the treatment of chronic pain.Methods: The number of study sites in each clinical trial and standardized effect size (SES) were extracted and computed. Standardized effect size was plotted against number of sites, and a two-piece linear model was fit to the plot. Ten studies were included.Results: The SES decreased linearly by 0.13 units for every 10 sites (p=0.037), from 0.75 to 0.36, until an inflection point of 60 sites, after which SES did not decline further. The total number of subjects required for 90% power to discriminate drug from placebo increased from 78 to 336 subjects going from 30 to 60 sites.Conclusion: Results showed that the number of sites was a source of loss of assay sensitivity in clinical trials, which may contribute to the well-known problem of failure to successfully transition from Phase 2 to Phase 3 clinical development. Potential solutions include minimizing the number of sites, more rigorous and validated training, central statistical monitoring with rapid correction of performance issues, and more rigorous subject and site selection.Keywords: randomized controlled trials, opioids, chronic pain, clinical trials, effect size, study site number

Objective To evaluate the long-term safety of NKTR-181, a novel mu-opioid receptor agonist that may have reduced human abuse potential, in patients with moderate to severe chronic low back pain (CLBP) or other chronic noncancer pain (CNP). Design Uncontrolled, multicenter, open-label, long-term study of NKTR-181 comprised of three periods: screening (≤21 days), treatment (52 weeks), and safety follow-up (∼14 days after the last dose of NKTR-181). Setting Multicenter, long-term clinical research study. Methods NKTR-181 administered at doses of 100–600 mg twice daily (BID) was evaluated in opioid-naïve and opioid-experienced patients. Patients were enrolled de novo or following completion of the randomized, placebo-controlled phase 3 efficacy study (SUMMIT-07). Safety assessments included adverse event documentation, measurements of opioid withdrawal, and clinical laboratory tests. Effectiveness was assessed using the modified Brief Pain Inventory Short Form (mBPI-SF). Results The study enrolled 638 patients. The most frequently reported treatment-emergent adverse events (TEAEs) were constipation (26%) and nausea (12%). Serious TEAEs, reported in 5% of patients, were deemed by investigators to be unrelated to NKTR-181. There were no deaths or reported cases of respiratory depression. A sustained reduction in mBPI-SF pain intensity and pain interference from baseline to study termination was observed throughout treatment. Only 2% of patients discontinued NKTR-181 due to lack of efficacy, and 11% discontinued due to treatment-related AEs. NKTR-181 doses of up to 600 mg BID were generally well tolerated, and patients experienced low rates of opioid-related adverse events. Conclusions The study results support the premise that NKTR-181 is a safe and effective option for patients with moderate to severe CLBP or CNP.

Objective: To prospectively evaluate the abuse potential of NKTR-181, a novel opioid analgesic, in two phase 3 clinical trials using a newly developed reporting system: the Misuse, Abuse, a...

Supplemental Digital Content is Available in the Text. NKTR-181 provides effective analgesia in patients with moderate-to-severe chronic low-back pain with low incidence of central nervous system side effects., NKTR-181, a new molecular entity, mu-opioid receptor agonist with an inherently slow rate of central nervous system (CNS) entry, was designed to provide analgesia while reducing abuse potential. This phase 3, enriched-enrollment, randomized-withdrawal trial evaluated the analgesic efficacy, safety, and tolerability of NKTR-181 in patients with chronic low-back pain (CLBP). Adults with moderate-to-severe CLBP refractory to nonopioid analgesics achieving an analgesic NKTR-181 dosage (100-400 mg twice daily) during the open-label titration period were randomized to continued NKTR-181 treatment, double-blind, or switched to placebo. The study was conducted at 55 sites in the United States. Of 1189 patients exposed to NKTR-181 during the titration period, 610 were randomized to NKTR-181 100 to 400 mg every 12 hours or placebo for 12 weeks. The primary outcome measure was change in weekly pain score (scale, 0-10) at 12 weeks from randomization baseline. Secondary outcome measures included responder rates defined by ≥30% and ≥50% improvement in pain score from screening to 12 weeks. Among 610 randomized patients, the mean pain score decreased from 6.73 to 2.32 during open-label titration. After randomization, the least-squares mean change in pain score was +0.92 for NKTR-181 vs +1.46 for placebo (P = 0.002). The ≥30%-improvement responder rate of NKTR-181 vs placebo was 71.2% vs 57.1% (P < 0.001), and the ≥50%-improvement responder rate was 51.1% vs 37.9% (P = 0.001). NKTR-181 was well tolerated with a low incidence (

There is tremendous interpatient variability in the response to analgesic therapy (even for efficacious treatments), which can be the source of great frustration in clinical practice. This has led to calls for “precision medicine” or personalized pain therapeutics (ie, empirically based algorithms that determine the optimal treatments, or treatment combinations, for individual patients) that would presumably improve both the clinical care of patients with pain and the success rates for putative analgesic drugs in phase 2 and 3 clinical trials. However, before implementing this approach, the characteristics of individual patients or subgroups of patients that increase or decrease the response to a specific treatment need to be identified. The challenge is to identify the measurable phenotypic characteristics of patients that are most predictive of individual variation in analgesic treatment outcomes, and the measurement tools that are best suited to evaluate these characteristics. In this article, we present evidence on the most promising of these phenotypic characteristics for use in future research, including psychosocial factors, symptom characteristics, sleep patterns, responses to noxious stimulation, endogenous pain-modulatory processes, and response to pharmacologic challenge. We provide evidence-based recommendations for core phenotyping domains and recommend measures of each domain.

Randomized clinical trials have demonstrated the efficacy of opioid analgesics for the treatment of acute and chronic pain conditions, and for some patients, these medications may be the only effective treatment available. Unfortunately, opioid analgesics are also associated with major risks (eg, opioid use disorder) and adverse outcomes (eg, respiratory depression and falls). The risks and adverse outcomes associated with opioid analgesics have prompted efforts to reduce their use in the treatment of both acute and chronic pain. This article presents Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) consensus recommendations for the design of opioid-sparing clinical trials. The recommendations presented in this article are based on the following definition of an opioid-sparing intervention: any intervention that (1) prevents the initiation of treatment with opioid analgesics, (2) decreases the duration of such treatment, (3) reduces the total dosages of opioids that are prescribed for or used by patients, or (4) reduces opioid-related adverse outcomes (without increasing opioid dosages), all without causing an unacceptable increase in pain. These recommendations are based on the results of a background review, presentations and discussions at an IMMPACT consensus meeting, and iterative drafts of this article modified to accommodate input from the co-authors. We discuss opioid sparing definitions, study objectives, outcome measures, the assessment of opioid-related adverse events, incorporation of adequate pain control in trial design, interpretation of research findings, and future research priorities to inform opioid-sparing trial methods. The considerations and recommendations presented in this article are meant to help guide the design, conduct, analysis, and interpretation of future trials.

Copyright © 2020 International Association for the Study of Pain., Interpreting randomized clinical trials (RCTs) is crucial to making decisions regarding the use of analgesic treatments in clinical practice. In this article, we report on an Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) consensus meeting organized by the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks, the purpose of which was to recommend approaches that facilitate interpretation of analgesic RCTs. We review issues to consider when drawing conclusions from RCTs, as well as common methods for reporting RCT results and the limitations of each method. These issues include the type of trial, study design, statistical analysis methods, magnitude of the estimated beneficial and harmful effects and associated precision, availability of alternative treatments and their benefit-risk profile, clinical importance of the change from baseline both within and between groups, presentation of the outcome data, and the limitations of the approaches used.

Objective To evaluate the association between the degree of response to placebo in migraine studies and the observed difference between drug and placebo across studies of preventative treatments for migraine. Methods A systematic review was performed using MEDLINE and the Cochrane Central Register of Controlled Clinical Trials from January 1988 to June 2019. Randomized, double-blind, parallel-group, placebo-controlled trials on oral or injection preventative treatments for migraine were included. Single- and multi-variable linear regression analyses were performed on the placebo-subtracted response rate (i.e. placebo responders subtracted from active responders), and the proportion of placebo responders. Fisher’s exact tests were performed on the level of placebo response and the success in meeting the study’s primary endpoint. Results After adjusting for route of administration and number of randomized subjects, there was a statistically significant association between the proportion of patients who were placebo responders and the placebo-subtracted response rate (b = −0.27, p = 0.02). There was a statistically significant difference in trial success rate (60%) between studies with ≤20% placebo responders and studies with > 30% placebo responders ( p = 0.03). Conclusion Considering the detrimental impact that high placebo response can have on clinical trials, it is imperative to find effective solutions to decrease the placebo response and increase assay sensitivity.

Kavita Gandhi,1 Wenhui Wei,2 Ahong Huang,3 Li Wang,3 Ravi Iyer,1 Nathaniel P Katz4,5 1Teva Pharmaceutical Industries, Frazer, PA, USA; 2Regeneron Pharmaceuticals, Tarrytown, NY, USA; 3STATinMED Research, Dallas, TX, USA; 4Analgesic Solutions, Wayland, MA, USA; 5Tufts University School of Medicine, Boston, MA, USACorrespondence: Nathaniel P KatzAnalgesic Solutions, 321 Commonwealth Road, Ste 204, Wayland, MA 01778, USATel +1 781 444-9605Fax +1 973 553-8888Email nkatz@analgesicsolutions.comBackground: Although opioids may be used in the management of pain in patients with osteoarthritis (OA), there is a dearth of real-world data characterizing opioid regimen failure in these patients.Objective: Using claims data, this study explored measures that may be potentially indicative of opioid treatment failure and the association of such potential failure with health care resource utilization (HRU) and costs.Patients and Methods: Using a national employer-sponsored insurance claims database covering the years 2011– 2016, this retrospective longitudinal study identified adults with hip/knee osteoarthritis who filled ≥ 1 opioid prescription (index event) and had continuous health plan enrollment 6 months pre- and ≥ 12 months post-index. Index opioid regimen intensity was defined in the 3-month post-index period by frequency, average daily dose, and duration of action. Possible index opioid regimen failure was defined as an increase in opioid regimen intensity, addition of a non-opioid pain medication, joint surgery, or opioid-abuse-related events. One-year follow-up HRU and costs were compared between those with possible treatment failure and those without.Results: Among 271,512 OA patients (61.5% knee; 11.1% hip; 27.4% both), 34.9% met the definition of possible index opioid regimen failure within a year: increased regimen intensity (16.1%), joint surgery (14.0%), addition of non-opioid pain medication (11.4%), and opioid-abuse-related events (1.9%). Rates of possible failure generally increased with higher index regimen intensity. Compared with those who did not fail, those who potentially failed their index treatment regimen had significantly higher HRU (P< 0.001), and all-cause ($36,699 vs $15,114) and osteoarthritis-related costs ($17,298 vs $1,967) (both P< 0.0001).Conclusion: Among OA patients treated with opioids, approximately one-third may fail their index opioid regimen within a year and incur significantly higher HRU and costs than those without. Further research is needed to validate these findings with clinical outcomes.Keywords: osteoarthritis, pain, opioids, treatment failure, health care resource use, costs

Analgesic trials often fail to show a significant effect even when medications with known efficacy are tested. This could be attributed to insufficient assay sensitivity of analgesic trials, which may be due, in part, to the insensitivity of pain-related outcome measures. The aim of this methodological study was to assess the responsiveness of evoked pain generated by the staircase procedure compared with other commonly used pain outcomes in knee osteoarthritis.This was a randomized, double-blind, placebo-controlled, cross-over trial of 1-week treatment of naproxen versus placebo. Participants were assigned to one of the 2 treatment sequences (naproxen-placebo or placebo-naproxen). Pain-at-rest, evoked pain using the Staircase-Evoked Pain Procedure (StEPP), pain diary, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) data were collected before and at the end of each treatment sequence.A total of 55 osteoarthritis patients (30 M, 25 F) completed the study. Among all pain assessments, evoked pain was the most sensitive outcome to detect treatment effects, with Standardized Effect Size (SES) of 0.47 followed by the WOMAC and pain-at-rest with SES of 0.43 and 0.36, respectively. Sample size calculations demonstrated that compared with spontaneous pain, the evoked pain model reduces required number of subjects by 40%.Study results support our hypothesis that evoked pain using the StEPP may demonstrate greater responsiveness to treatment effects compared with traditional pain-related outcome measures. Accordingly, these results may facilitate development and validation of other chronic pain-related evoked pain models, which could contribute to future research and development of new analgesics.

The growing need for symptomatic treatment of post-traumatic neuropathic pain (PTNP) continues to be unmet. Studies evaluating the efficacy of pregabalin for reducing neuropathic pain following trauma and surgery yielded positive results over ≤ 8-week treatment. To assess the efficacy and tolerability of pregabalin over 3 months in patients with PTNP, a randomized, double-blind, placebo-controlled, parallel-group trial evaluated patients with PTNP at 101 centers in 11 countries—the longest, largest such trial. Adults diagnosed with PTNP were randomly assigned (1:1) to 15 weeks of pregabalin (flexibly dosed 150–600 mg/day) or matching placebo. Primary efficacy analysis was by mixed-model repeated measures comparing change from baseline to week 15 in weekly mean pain scores between active and placebo groups. Evaluable patients included 274 in the pregabalin group and 265 in the placebo group. Trauma was surgical in 49.6% of patients, non-surgical in the remainder. The primary efficacy analysis showed no statistically significant difference between pregabalin and placebo groups in the change from baseline to week 15 [mean difference, − 0.22 points (95% confidence interval, 0.54–0.10); p = 0.1823]. However, comparisons for key secondary outcome measures yielded p values

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and potentially dose-limiting side effect of neurotoxic chemotherapies. No therapies are available to prevent CIPN. The small number of positive randomized clinical trials (RCTs) evaluating preventive therapies for CIPN provide little guidance to inform the design of future trials. Moreover, the lack of consensus regarding major design features in this area poses challenges to development of new therapies. An Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities and Networks (ACTTION)–Consortium on Clinical Endpoints and Procedures for Peripheral Neuropathy Trials (CONCEPPT) meeting attended by neurologists, oncologists, pharmacists, clinical trialists, statisticians, and regulatory experts was convened to discuss design considerations and provide recommendations for CIPN prevention trials. This article outlines considerations related to design of RCTs that evaluate preventive therapies for CIPN including (1) selection of eligibility criteria (e.g., cancer types, chemotherapy types, inclusion of preexisting neuropathy); (2) selection of outcome measures and endpoints, including those that incorporate alterations in chemotherapy dosing, which may affect the rate of CIPN development and its severity; (3) potential effects of the investigational therapy on the efficacy of chemotherapy; and (4) sample size estimation. Our hope is that attention to the design considerations and recommendations outlined in this article will improve the quality and assay sensitivity of CIPN prevention trials and thereby accelerate the identification of efficacious therapies.

Integrating information on physical function and pain intensity into a composite measure may provide a useful method for assessing treatment efficacy in clinical trials of chronic pain. Accordingly, we evaluated composite outcomes in trials of duloxetine, gabapentin, and pregabalin. Data on 2287 patients in 9 trials for painful diabetic peripheral neuropathy (DPN) and 1513 patients in 6 trials for postherpetic neuralgia (PHN) were analyzed. All trials assessed pain intensity on a 0 to 10 numeric rating scale and physical function with the 10-item subscale of the Short Form-36, ranging 0 to 100 with higher scores indicating better function. Correlation between change in pain intensity from baseline to posttreatment and change in physical function was small in DPN (ρ = -0.22; P < 0.001) and nonsignificant in PHN (ρ = -0.05; P = 0.08). Assay sensitivities of 10 composite outcomes were examined in a random subsample of patients enrolled in pregabalin trials for DPN and PHN. Of these, a responder outcome of ≥50% improvement in pain intensity, or a ≥20% improvement in pain intensity and ≥30% improvement in physical function was not only significantly associated with pregabalin vs placebo in the development cohorts for both pain conditions but also in the validation cohorts. Furthermore, this composite outcome was cross-validated in trials of gabapentin for PHN and duloxetine for DPN, and had slightly lower number needed to treat than a standard responder outcome of ≥50% reduction in pain intensity. In summary, this study identified a composite outcome of pain intensity and physical function that may improve the assay sensitivity of future neuropathic pain trials.

Diana S Meske,1 Oluwadolapo D Lawal,1 Harrison Elder,1 Valerie Langberg,2 Florence Paillard,1 Nathaniel Katz1,3 1Analgesic Solutions, Natick, MA, USA, 2The Center for Evidence Synthesis in Health, Brown University, Providence, RI, USA, 3Department of Anesthesiology and Perioperative Medicine, Tufts University School of Medicine, Boston, MA, USA Introduction: Opioids have been used for millennia for the treatment of pain. However, the long-term efficacy of opioids to treat chronic non-cancer pain continues to be debated. To evaluate opioids’ efficacy in chronic non-cancer pain, we performed a meta-analysis of published clinical trials for μ-opioid receptor agonists performed for US Food and Drug Administration approval. Methods: MEDLINE and Cochrane trial register were searched for enriched enrollment randomized withdrawal studies (before June 2016). Selection criteria included: adults, ≥10 subjects per arm, any chronic pain condition, double-blind treatment period lasting ≥12 weeks, and all μ-agonist opioids approved in the USA. Results: Fifteen studies met criteria. Opioid efficacy was statistically significant (p

Background: The aim of this study was to determine the current magnitude and characteristics of intravenous patient-controlled analgesia (IV-PCA) errors, and to identify opportunities for improving the PCA modality. Methods: We conducted a descriptive analysis of IV-PCA medication errors submitted to the MEDMARX database. Events were restricted to those occurring in inpatient hospital settings between 1 January 2005 and 31 December 2015. IV-PCA errors were classified by error category, cause of error, error type, level of care rendered, and actions taken. Results: A total of 1948 IV-PCA errors were identified as potential errors (3.9%), nonharmful errors (89.5%), or harmful errors (6.7%) based on the National Coordinating Council for Medication Error Reporting and Prevention taxonomy for categorizing medication errors. Of these, 19.1% required a clinical intervention to address the deleterious effects of the error, indicating an underestimation of the risks associated with IV-PCA errors. The most frequent types of errors were improper dose/quantity (43.2%) and omission errors (19.9%). While human performance deficit was the leading cause of error (50.2%), other common causes included failure to follow procedure and protocol (42.2%) and improper use of the pump (22.7%). Although remedial actions were often taken to prevent error recurrence, actions were taken to rectify the systemic deficits that led to errors in only a minority of cases (11.8%). Conclusion: Preventable errors continue to pose unnecessary risks to patients receiving IV-PCA. Multimodal analgesic regimens and novel PCA systems that reduce human error are needed to prevent errors while preserving the advantages of PCA for the management of acute pain.

Background: Intra-articular corticosteroids relieve osteoarthritis pain, but rapid systemic absorption limits efficacy. FX006, a novel, microsphere-based, extended-release triamcinolone acetonide (TA) formulation, prolongs TA joint residence and reduces systemic exposure compared with standard TA crystalline suspension (TAcs). We assessed symptomatic benefits and safety of FX006 compared with saline-solution placebo and TAcs. Methods: In this Phase-3, multicenter, double-blinded, 24-week study, adults ≥40 years of age with knee osteoarthritis (Kellgren-Lawrence grade 2 or 3) and average-daily-pain (ADP)-intensity scores of ≥5 and ≤9 (0 to 10 numeric rating scale) were centrally randomized (1:1:1) to a single intra-articular injection of FX006 (32 mg), saline-solution placebo, or TAcs (40 mg). The primary end point was change from baseline to week 12 in weekly mean ADP-intensity scores for FX006 compared with saline-solution placebo. Secondary end points were area-under-effect (AUE) curves of the change in weekly mean ADP-intensity scores from baseline to week 12 for FX006 compared with saline-solution placebo, AUE curves of the change in weekly mean ADP-intensity scores from baseline to week 12 for FX006 compared with TAcs, change in weekly mean ADP-intensity scores from baseline to week 12 for FX006 compared with TAcs, and AUE curves of the change in weekly mean ADP-intensity scores from baseline to week 24 for FX006 compared with saline-solution placebo. Exploratory end points included week-12 changes in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Knee Injury and Osteoarthritis Outcome Score Quality of Life (KOOS-QOL) subscale scores for FX006 compared with saline-solution placebo and TAcs. Adverse events were elicited at each inpatient visit. Results: The primary end point was met. Among 484 treated patients (n = 161 for FX006, n = 162 for saline-solution placebo, and n = 161 for TAcs), FX006 provided significant week-12 improvement in ADP intensity compared with that observed for saline-solution placebo (least-squares mean change from baseline: −3.12 versus −2.14; p < 0.0001) indicating ∼50% improvement. FX006 afforded improvements over saline-solution placebo for all secondary and exploratory end points (p < 0.05). Improvements in osteoarthritis pain were not significant for FX006 compared with TAcs using the ADP-based secondary measures. Exploratory analyses of WOMAC-A, B, and C and KOOS-QOL subscales favored FX006 (p ≤ 0.05). Adverse events were generally mild, occurring at similar frequencies across treatments. Conclusions: FX006 provided significant, clinically meaningful pain reduction compared with saline-solution placebo at week 12 (primary end point). Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Background: Intra-articular bleeding (hemarthrosis) accounts for 80-90% (Roosendaal, et. al. Semin Thromb Hemost . 2003;29:37) of all bleeds and more than 90% of serious bleeding events in patients with severe hemophilia (Valentino. J Thromb Haemost . 2010;8:1895). Recurrent hemarthroses result in progressive joint damage and the development of hemophilic arthropathy (HA) in up to 50% of adults with hemophilia (Forsyth, et al. Haemophilia . 2014;20:44). Acetaminophen is commonly prescribed for pain due to HA yet has limited efficacy at therapeutic doses (Rodriguez-Merchan. Blood Rev. 2018;32:116). Traditional non-steroidal anti-inflammatory drugs (tNSAIDs) inhibit platelet function and cause gastrointestinal (GI) complications including bleeding, both of which can be harmful in patients with hemophilia (Rodriguez-Merchan. Blood Rev. 2018;32:116; Brooks, et al. Rheumatology . 1999;38(8):779). Opioids are prescribed in over 60% of patients with HA(Witkop, et al. Haemophilia. 2012;18:e115) despite dependence, potential for abuse, and an increased risk of falls and other opioid-related injury (Rodriguez-Merchan. Blood Rev. 2018;32:116). Given an unmet need in pain management for HA, alternate approaches are needed. TRM-201 (rofecoxib) is a cyclooxygenase-2 (COX-2) selective NSAID with no impact on platelet function and a lower GI risk than tNSAIDs (Vioxx (rofecoxib) package insert. Merck & Co. I, ed. Whitehouse Station, NJ, 2004). The RESET-HA study is designed to evaluate the efficacy and safety of rofecoxib for HA pain management. Methods/Design: RESET-HA is a multi-national, randomized, double-blind study to evaluate the efficacy and safety of rofecoxib in hemophilia A or B patients with diagnosed HA, aged 12 to 75 years and is based on a previous pilot study (Tsoukas, et al. Blood, 2006;107:1785). Patients must have a history of joint bleeding, and chronic symptomatic pain in one or more joint(s) on 20 of the 30 days prior to screening. Exclusion criteria include use of opioids for greater than 4 days/week, or opioid transdermal patches in the 30 days prior to screening, history of GI perforation, ulcer or bleeding, peptic ulcer disease and major cardiac ischemic symptoms or events. Randomized patients (n=80 per arm) are washed out of analgesics prior to daily administration of TRM-201 (17.5 mg/day) or placebo for 12 weeks (Part I) during which acetaminophen (Stage-1) and acetaminophen plus codeine (Stage-2) are available as rescue medication (where available and acceptable to the patient and study doctor). The patient assessment of hemophilic arthropathy pain, a 0- to 10-point numeric rating scale validated for the assessment of pain across many disease states, is recorded daily. The primary endpoint is the placebo adjusted change from baseline in weekly average of patient assessment of daily HA pain score at Week 12. Key secondary endpoints include patient assessments using the PROMIS physical function instrument and pain interference from the Brief Pain Inventory. Sleep disturbance is also measured using the PROMIS instrument. The study explores the efficacy of rofecoxib on the number of suspected joint bleeds and on the amount of rescue medication used. Following Part I, all study patients (regardless of original randomization arm) receive rofecoxib 17.5 mg once daily for up to 12 additional months (Part II). During Part II of the study, only acetaminophen will be provided as rescue medication. Discussion: The RESET-HA study is intended to evaluate the efficacy and safety of TRM-201 in patients with HA and is the first Phase III trial ever conducted to assess a treatment for HA pain. Pain management in HA requires analgesic anti-inflammatory treatment that does not exacerbate bleeding. Rofecoxib has been shown to have no effect on platelet function, even at supratherapeutic doses(Vioxx (rofecoxib) package insert. Merck & Co. Whitehouse Station, NJ, 2004), a decreased risk of GI side effects, including GI bleeding compared with tNSAIDs, and no greater cardiovascular risk than equipotent doses of COX-2 selective and tNSAIDs (U.S. Food and Drug Administration. J Pain Palliat Care Pharmacother. 2005;19:83). TRM-201 is anticipated to provide analgesic efficacy, with an acceptable tolerability and safety profile, and could become a new treatment option that may possibly facilitate the avoidance of opioid use in patients with HA. (NCT04684511) Disclosures Boice: Tremeau Pharmaceuticals Inc.: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Buckner: Novo Nordisk: Honoraria; American Thrombosis: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Honoraria; Genetech: Honoraria; Spark: Honoraria; Sanofi: Honoraria; Bayer: Honoraria; Pfizer: Honoraria; Takeda: Honoraria; Tremeau Pharmaceuticals: Consultancy, Honoraria; uniQure: Consultancy, Honoraria; BioMarin: Consultancy, Honoraria; Hemostasis Network: Membership on an entity's Board of Directors or advisory committees. Croteau: Tremeau Pharmaceuticals,Inc: Consultancy. Katz: Tremeau Pharmaceuticals,Inc: Consultancy. Sidonio: Takeda: Consultancy, Research Funding; Octapharma: Consultancy, Research Funding; Catalyst: Consultancy; Guardian Therapeutics: Consultancy; Bayer: Consultancy; Novo Nordisk: Consultancy; Biomarin: Consultancy; Pfizer: Consultancy; Genentech: Consultancy, Research Funding. Bolognese: Tremeau Pharmaceuticals,Inc: Consultancy. Garfield: Tremeau Pharmaceuticals,Inc: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Corrigon: Tremeau Pharmaceuticals,Inc: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Walsh: Genentech: Consultancy; Biomarin: Consultancy; Takeda: Consultancy; Novo Nordisk: Consultancy; Tremeau: Consultancy.

The desire to reduce high placebo response rates in clinical trials is a popular concept. However, few studies have rigorously examined the effectiveness of methods to control for placebo responses that are relevant to randomized controlled trials. The primary objective of this review was to evaluate the effect of experimental placebo manipulations in randomized controlled trials (RCTs). We critically reviewed studies designed to manipulate placebo responses including positive expectations regarding the effectiveness of the placebo treatment, manipulating the time spent with subjects, and training study staff and subjects to accurately report symptom severity. These efforts have generally resulted in reduced placebo response and improved discrimination between drug and placebo. Interventions that neutralize staff and subject expectations and improve the ability of subjects to accurately report symptom severity have shown the most promise. Reduction of the placebo response has the potential to accelerate the development of new therapeutics.

Objectives: To evaluate potential for and incidence of aberrant drug-related behaviors among patients with chronic, moderate-to-severe pain in a primary care setting and to determine investigator compliance with universal precautions (UP) approach to pain management. Design: Open label, multicenter. Setting: Primary care centers (N = 281) across the United States. Patients: Opioid naive and opioid experienced with chronic, moderate-to-severe pain (N = 1,487). Interventions: Morphine sulfate extended-release capsules for ≤4 months. Tools comprising UP approach were treatment agreement, card for obtaining/tracking prescriptions, Screener and Opioid Assessment for Patients with Pain®-Revised questionnaire, pill counts, pain-patient follow-up tool, investigator assessment/plan, and urine drug screens (UDSs). Outcome measures: Proportion of patients at low, moderate, and high risk of opioid misuse/abuse based on prespecified criteria and investigator judgment, proportion of patients with aberrant drug-related behaviors, and proportion of investigators compliant with UP approach. Results: Patients were primarily white (87 percent), women (57 percent); mean age, 53 years (range, 21-92 years). At baseline, 47 percent were considered low risk for opioid misuse/abuse, 52 percent moderate, and 1 percent high. UDSs were positive for illicit/nonprescribed drugs in a proportion of patients throughout the study. Overall, 64 percent of investigators were compliant with major components of UP approach in ≥75 percent of their patients. However, there was a tendency for investigators to assign risk levels for opioid misuse/abuse as lower than protocol specified. Conclusions: Most patients in these primary care study centers were categorized as at least moderate risk for opioid misuse/abuse at baseline. Most primary care investigators complied with the UP approach to pain management and risk assessment. The completion of the brief training and clinical use of the tools during the study led to retained behavior change, but there was a tendency for investigators to assign lower risk levels than those that were protocol-specified, suggesting a need for better understanding of factors influencing investigator decisions.

Supplemental Digital Content is Available in the Text. Neublastin showed some evidence of pain relief among patients with painful lumbosacral radiculopathy; however, there was no clear dose–response relationship., Neublastin (BG00010) is a first-in-class, glial cell–derived neurotrophic factor shown in preclinical studies and an early clinical trial to have potential for the treatment of neuropathic pain. SPRINT was a phase 2, multicenter, double-blinded, placebo-controlled study to evaluate efficacy/safety of 5 neublastin doses (50, 150, 400, 800, and 1200 μg/kg) administered as an intravenous injection 3 times/week for 1 week in patients with chronic painful lumbosacral radiculopathy, utilizing Bayesian response-adaptive study design. Primary endpoint was change from baseline in mean 24-hour average general pain intensity over a 5-day period (week 1) after the last dose, analyzed using a Bayesian normal dynamic linear model. One hundred seventy-six patients were randomized and received treatment (placebo n = 48, 50 μg/kg n = 38, 150 μg/kg n = 13, 400 μg/kg n = 16, 800 μg/kg n = 20, 1200 μg/kg n = 41). Among the tested neublastin doses, the lowest dose (50 μg/kg) showed the greatest difference from placebo for change from baseline in mean average general pain intensity at week 1 after last dose, followed by the highest dose (1200 μg/kg) (posterior mean difference −1.36 [95% credible interval −2.22 to −0.52] and −0.75 [−1.59 to 0.08], respectively). Similar trends were observed in secondary efficacy endpoints. The most common adverse event in all neublastin dose groups was pruritus (79% vs 10% with placebo). There was no dose–response relationship with respect to primary/secondary efficacy outcomes or incidence of pruritus, despite dose-proportional increases in serum neublastin concentrations. In conclusion, while this study showed some evidence of pain relief with neublastin, particularly at the lowest dose, there was no clear dose–response relationship for pain reduction or the most common adverse event of pruritus.

Clinical trials of analgesics have been plagued with poor assay sensitivity due, in part, to variability in subjects' pain reporting. Herein, we develop and evaluate the focused analgesia selection test (FAST), a method to measure patients' pain reporting skills. Subjects with osteoarthritis of the hip, knee, and/or ankle with pain intensity of ≥3/10 on a 0-10 numerical rating scale were enrolled. Subjects underwent the FAST procedure, which consists of recording subjects' pain reports in response to repeated administration of thermal noxious stimuli of various intensities applied on the arm with the Medoc® Thermal Sensory Analyzer II. Subjects also rated non-noxious stimuli consisting of visual contrast rating. After performing an exercise task, subjects also rated clinical pain and were asked to report whether their pain had increased, decreased, or stayed the same. Overall, 88 subjects were enrolled, and 83 were included in the analyses. FAST's outcomes including the R2, intraclass correlation coefficient (ICC), and coefficient of variation (CoV) indicated that subjects' pain reporting skills were widely distributed. Higher FAST ICC significantly predicted greater changes in clinical pain following exercise (p=0.017), whereas the visual contrast test did not predict postexercise pain. FAST is the first method that measures subjects' pain reporting skills. Using FAST to enrich clinical trials with "good" pain reporters (with high FAST ICC) could increase assay sensitivity. Further evaluation of FAST is ongoing.

Aims: Opioids do not represent standard therapy for endometriosis; however, women with endometriosis are frequently prescribed an opioid to manage related abdominal or pelvic pain. The aim of this study was to evaluate the impact of opioid use on endometriosis-related economic and healthcare burden in the United States. Materials and methods: We performed a retrospective, propensity-matched cohort analysis of the Truven MarketScan Commercial database from 1 January 2011 to 31 December 2016. Eligible women had at least 1 inpatient or 2 outpatient codes for endometriosis and 12 months of continuous enrollment before and after the index date (i.e. first recorded endometriosis diagnosis). The primary analysis examined healthcare costs and utilization for 12 months after the index date in women who filled at least 1 opioid prescription versus those who did not. The secondary analysis examined healthcare costs and utilization by the pattern of opioid use. Results: The primary analysis matched 43,516 women across 2 groups and the secondary analysis matched 13,230 women across 5 groups. In the primary analysis, total 12-month healthcare costs were significantly higher in the opioid group compared to the non-opioid group ($29,236.00 vs. $18,466.00, respectively; p Limitations: Retrospective design and inability to confirm whether filled opioid prescriptions were actually taken. Conclusions: Filling an opioid prescription within 1 year after an endometriosis diagnosis was associated with significant excess healthcare burden. Patients prescribed an opioid may experience inadequate symptom management and benefit from the use of disease-specific, non-opioid therapies.

Objective: To determine long-term safety and effectiveness of repeat treatments with a high concentration capsaicin patch. Methods: In this 52-week, open-label, randomized controlled study, patients with painful diabetic peripheral neuropathy (PDPN) received either capsaicin patch: (30- or 60-min; 1–7 treatments to the feet) plus SOC or SOC alone. Effectiveness was assessed, by changes from baseline to end of study (EoS), in average and severity of pain, pain interference with daily function (Brief Pain Inventory-Diabetic Neuropathy version), responder rates, Patient Global Impression of Change (PGIC), and EuroQol 5-dimension (EQ-5D) questionnaire. Results: 468 patients were randomized (n=156 and n=157, 30 and 60-min respectively; SOC alone, n=155). Safety data have been reported previously. Changes in average pain from baseline to EoS (mean percentage (SD)) were: 30-min, −37.5% (32.9); 60-min, −40.8% (39.7); SOC alone, −13.9% (74.6). The difference between groups increased progressively from −17.7% and −18.6% at Month 1 for 30- and 60-min., respectively, to −21.9% and −24% at Month 12. More 30% responders occurred in the capsaicin groups (30-min, 67.3%; 60-min, 67.5%) and more felt: very much or much improved” (30-min, 24.2%; 60-min, 24.5%), compared with SOC alone (40.6% and 9.5% respectively). A greater mean improvement in EQ-5D utility index and EQ-5D visual analog scale score, from baseline to Month 12, was observed with the 30-min (0.12) and 60-min (0.15) versus SOC alone (0.07) and mean (SD), 30–min (10.4 [18.5]) and 60-min (11.2 [21.4]) versus SOC alone (5.5 [18.1]) respectively. Conclusion: Capsaicin 8% patch showed differential effectiveness over SOC alone, further increasing with repeat treatments.

Previous studies have shown a robust correlation between variability of clinical pain scores and responsiveness to placebo (but not active drug) in pain studies, but explanations for these relationships are lacking. We investigated this further by assessing relationship between the Focused Analgesia Selection Test (FAST), a psychophysical method that quantifies pain reporting variability in response to experimental stimuli, variability of daily clinical pain scores as captured using diary, and response to treatment in the context of a randomized controlled crossover trial of naproxen vs placebo in knee osteoarthritis. Evoked pain using the Staircase-Evoked Pain Procedure served as the primary efficacy endpoint. Variability of daily pain scores and the FAST were assessed at baseline. Fifty-five subjects completed the study and were included in the analyses. Our results indicated a statistically significant, moderate linear relationship between variability of clinical and experimental pain reports (r = -0.416, P = 0.004). Both correlated with the placebo response (r = 0.393, P = 0.004; r =-0.371, P = 0.009; respectively), but only the FAST predicted the treatment difference between naproxen and placebo, as demonstrated both in a regression model (P = 0.002, Beta = 0.456, t = 3.342) and in a receiver operating characteristic curve (0.721) analysis. Our results extend previous findings to include a correlation between experimental pain variability and the placebo response and suggest that experimental pain variability is a better predictor of patients who respond preferentially to drug over placebo. A theoretical model unifying these observations is proposed, and practical implications are discussed.

Background and Objectives Inappropriate use of analgesic drugs has become increasingly pervasive over the past decade. Currently, drug abuse potential is primarily assessed post-marketing; no validated tools are available to assess this potential in phase II and III clinical trials. This paper describes the development and feasibility testing of a Misuse, Abuse, and Diversion Drug Event Reporting System (MADDERS), which aims to identify potentially abuse-related events and classify them according to a recently developed classification scheme, allowing the quantification of these events in clinical trials. Methods The system was initially conceived and designed with input from experts and patients, followed by field-testing to assess its feasibility and content validity in both completed and ongoing clinical trials. Results The results suggest that MADDERS is a feasible system with initial validity. It showed higher rates of the triggering events in subjects taking medications with known abuse potential than in patients taking medications without abuse potential. Additionally, experts agreed on the classification of most abuse-related events in MADDERS. Discussion and Conclusions MADDERS is a new systematic approach to collect information on potentially abuse-related events in clinical trials and classify them. The system has demonstrated feasibility for implementation. Additional research is ongoing to further evaluate its validity. Scientific Significance Currently, there are no validated tools to assess drug abuse potential during clinical trials. Because of its ease of implementation, its systematic approach, and its preliminary validation results, MADDERS could provide such a tool for clinical trials. (Am J Addict 2016;XX:1–11).

Thorough assessment and reporting of adverse events (AEs) facilitates a detailed understanding of a treatment's risk–benefit profile. Although the Consolidated Standards of Reporting Trials (CONSORT) 2004 statement provides recommendations regarding AE reporting, adherence to these standards is often inadequate. We investigated AE reporting in clinical trials of intravenous and invasive pain treatments published in 6 major anesthesiology and pain journals between 2000 to 2003 and 2006 to 2012. We examined whether AE reporting improved after publication of the 2004 CONSORT recommendations and also comprehensively reviewed AE assessment using the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) AE reporting recommendations. No improvement was found overall in CONSORT harms reporting scores from pre- to postpublication of the CONSORT recommendations, with only 5 of 10 fulfilled on average. AE reporting assessed using the ACTTION coding manual was generally inadequate, and 8% of articles failed to report any AE information at all. Anesthesiology and pain journals were similar in AE reporting quality, although industry-sponsored trials reported more AE information than nonindustry sponsored trials. Improvement is needed in AE reporting in analgesic clinical trials. The CONSORT checklist and ACTTION AE recommendations can assist investigators and editors in improving clinical trial transparency and quality. Perspective This systematic review of AE reporting in intravenous and invasive pain treatment trials shows that little improvement has been made since the 2004 CONSORT harms reporting guidelines. Better assessment and reporting of treatment AEs is necessary to understand the full clinical effect of intravenous and invasive treatments.

Cross-over trials are typically more efficient than parallel group trials in that the sample size required to yield a desired power is substantially smaller. It is important, however, to consider some issues specific to cross-over trials when designing and reporting them, and when evaluating the published results of such trials. This systematic review evaluated the quality of reporting and its evolution over time in articles of cross-over clinical trials of pharmacologic treatments for chronic pain published between 1993 and 2013. Seventy-six (61%) articles reported a within-subject primary analysis, or if no primary analysis was identified, reported at least 1 within-subject analysis, which is required to achieve the gain in power associated with the cross-over design. For 39 (31%) articles, it was unclear whether analyses conducted were within-subject or between-group. Only 36 (29%) articles reported a method to accommodate missing data (eg, last observation carried forward, n = 29), and of those, just 14 included subjects in the analysis who provided data from only 1 period. Of the articles that identified a within-subject primary analysis, 21 (51%) provided sufficient information for the results to be included in a meta-analysis (ie, estimates of the within-subject treatment effect and variability). These results and others presented in this article demonstrate deficiencies in reporting of cross-over trials for analgesic treatments. Clearer reporting in future trials could improve readers' ability to critically evaluate the results, use these data in meta-analyses, and plan future trials. Recommendations for proper reporting of cross-over trials that apply to any condition are provided.

A buccal film of buprenorphine (BBUP) was evaluated for safety and efficacy in a multicenter, double-blind, placebo-controlled, enriched-enrollment, randomized-withdrawal study in opioid-experienced patients (30 to ≤160 mg/d morphine sulfate equivalent) with moderate to severe chronic low back pain taking around-the-clock opioid analgesics. Patients' opioid doses were tapered to ≤30 mg morphine sulfate equivalent before open-label titration with BBUP (range, 150-900 μg every 12 hours). Patients who responded (received adequate analgesia that was generally well tolerated for 14 days) were randomized to receive buprenorphine (n = 254) or placebo (n = 257) buccal film. The primary efficacy variable was the change from baseline to week 12 of double-blind treatment in mean average daily pain-intensity scores using a rating scale of 0 (no pain) to 10 (worst pain imaginable). In the intent-to-treat population, mean pain scores were 6.7 after opioid taper and declined to 2.8 after the BBUP titration period. After randomization, mean pain scores were lower in the BBUP group than in the placebo group; the difference between groups in the mean change from baseline to week 12 was -0.98 (95% CI, -1.32 to -0.64; P < 0.001). A significantly larger percentage of patients receiving BBUP than placebo had pain reductions ≥30% and ≥50% (P < 0.001 for both). In the double-blind portion of the study, the only adverse event reported more frequently with BBUP than placebo and in ≥5% of patients was vomiting (5.5% vs 2.3%). These findings demonstrate the efficacy and tolerability of BBUP in opioid-experienced patients taking around-the-clock opioid treatment for chronic low back pain.

This article summarizes the results of a meeting convened by the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) on key considerations and best practices governing the design of acute pain clinical trials. We discuss the role of early phase clinical trials, including pharmacokinetic-pharmacodynamic (PK-PD) trials, and the value of including both placebo and active standards of comparison in acute pain trials. This article focuses on single-dose and short-duration trials with emphasis on the perioperative and study design factors that influence assay sensitivity. Recommendations are presented on assessment measures, study designs, and operational factors. Although most of the methodological advances have come from studies of postoperative pain after dental impaction, bunionectomy, and other surgeries, the design considerations discussed are applicable to many other acute pain studies conducted in different settings.

This article provides a set of practical, evidence-based suggestions for designing and executing chronic pain clinical trials in a manner that minimizes measurement error., The purpose of this article is to provide readers with a basis for understanding the emerging science of clinical trials and to provide a set of practical, evidence-based suggestions for designing and executing confirmatory clinical trials in a manner that minimizes measurement error. The most important step in creating a mindset of quality clinical research is to abandon the antiquated concept that clinical trials are a method for capturing data from clinical practice and shifting to a concept of the clinical trial as a measurement system, consisting of an interconnected set of processes, each of which must be in calibration for the trial to generate an accurate and reliable estimate of the efficacy (and safety) of a given treatment. The status quo of inaccurate, unreliable, and protracted clinical trials is unacceptable and unsustainable. This article gathers aspects of study design and conduct under a single broad umbrella of techniques available to improve the accuracy and reliability of confirmatory clinical trials across traditional domain boundaries.

Introduction:. NEO6860 is a TRPV1 antagonist when activated by capsaicin but not by heat or pH, developed to relieve pain without the adverse events reported with non–modality-selective TRPV1 antagonists. Objective:. The primary Objective of this study was to evaluate the analgesic efficacy and safety of NEO6860 after 1 day oral dosing in patients with Kellgren-Lawrence stage I, II or III osteoarthritis of the knee. Method:. This randomized, double-blinded, 3-period crossover, phase II study compared 1 day (2 doses) of NEO6860 (500 mg twice a day), placebo, and naproxen in 54 patients with osteoarthritis knee pain. Primary endpoint was reduction in pain intensity (PI) on Numerical Rating Scale after exercise, using the staircase test, 8 hours after dose. Results:. Level of PI, compared with baseline, was numerically lower during NEO6860 and naproxen periods vs placebo at 3 and 24 hours, but not at 8 hours after first dose. A statistically significant effect for naproxen and a trend for NEO6860 were observed at 3 and 24 hours. Least square means' (95% confidence interval) change in PI at 24 hours was −0.67 (−1.09 to −0.26), −0.97 (−1.39 to −0.55), −0.29 (−0.71 to 0.13) for NEO6860, naproxen, and placebo, respectively. NEO6860 exposure was ∼1.6 times higher compared with previous phase I. In this study, NEO6860 safety profile was less favorable than naproxen or placebo. Possibly NEO6860-related adverse events included: feel hot, headache, nausea, dizziness, fatigue, hypoaesthesia, and increased blood pressure. Conclusion:. In this exploratory study, NEO6860 did not statistically significantly outperform placebo but showed an analgesic trend, without impacting body temperature and heat pain perception. Further studies are warranted to explore the potential of NEO6860 in other pain indications. We intent to optimize the dose and evaluate analgesic synergism with other mechanism.

Background The aim of this study is to determine the characteristics, magnitude, and the quality of reporting of mandated events involving intravenous patient-controlled analgesia (IV-PCA) devices in the Food and Drug Administration (FDA) Manufacturer and User Facility Device Experience (MAUDE) database; a postmarket surveillance system. Methods We utilized a mixed-methods approach to systematically characterize structured data and text narratives associated with IV-PCA events submitted to MAUDE between 1 January 2011 and 12 September 2016. Results Of 1,430 IV-PCA events reported during the study period, 6.4% were adverse events (AEs) as identified via structured data fields in the MEDWATCH forms. Upon qualitative review of the narrative texts, 11.0% of events were associated with an unfavorable clinical outcome, which was 71% higher than the incidence of the adverse outcomes reported using the structured data fields. Device-related issues, which were mostly preventable, accounted for 86.9% of events. Of 65 reportable events submitted by manufacturers, 18.5% did not comply with reporting requirements as mandated by law. Conclusion Patients on IV-PCA continue to experience serious complications as a result of preventable errors. Multi-modal interventions including educational training and the development and adoption of PCA devices with improved safety features are needed to improve safety.

The progression from prescription opioid (RXO) abuse to RXO addiction is not well understood in adolescents, nor is the progression from RXO addiction to heroin abuse. The purpose of this pilot study was to characterize the development of RXO drug abuse, RXO drug addiction, and heroin abuse in a small cohort of adolescents recovering from opioid addiction at Massachusetts Recovery High Schools (RHS). A self-report questionnaire was administered to 31 adolescent, former RXO abusers across two Massachusetts RHS. RXO abuse was primarily initiated due to curiosity; RXOs were initially obtained through illicit and licit methods. Fifty-eight percent (N = 18) of the RXO abusers became addicted to RXOs. Many addicted adolescents initiated RXO abuse under the influence of marijuana, yet believed that they became addicted due to the stress from difficult life situations. A subgroup indicated they abused and became addicted to RXOs that had been obtained from legitimate prescriptions due to their pain. Sixte...

Opioid analgesics are commonly used for the treatment of chronic low back pain (CLBP); however, abuse potential is a major concern. This study used a randomized, double-blind, placebo-controlled, enriched-enrollment randomized-withdrawal study design to evaluate the safety, tolerability, and analgesic efficacy of an abuse-deterrent formulation of extended-release oxycodone, Xtampza ER, in opioid-naive and opioid-experienced adults with moderate-to-severe CLBP. Patients entered an open-label titration phase (N = 740); those who were successfully titrated on Xtampza ER (≥40 to ≤160 mg oxycodone hydrochloride equivalent per day) were randomized to active drug (N = 193) or placebo (N = 196) for 12 weeks. Primary efficacy results showed a statistically significant difference in average pain intensity from randomization baseline to treatment week 12 between the Xtampza ER and placebo groups (mean [±SE], -1.56 [0.267]; P < 0.0001). All sensitivity analyses results supported the primary result of the study. Secondary efficacy outcomes indicated that Xtampza ER vs placebo had more patients with improvement in patient global impression of change (26.4% vs 14.3%; P < 0.0001), longer time-to-exit from the study (58 vs 35 days; P = 0.0102), and a greater proportion of patients with ≥30% (49.2% vs 33.2%; P = 0.0013) and ≥50% (38.3% vs 24.5%; P = 0.0032) improvement in pain intensity. There was less rescue medication (acetaminophen) use in the Xtampza ER treatment group than in the placebo group. Xtampza ER had an adverse event profile consistent with other opioids and was well tolerated; no new safety concerns were identified. In conclusion, Xtampza ER resulted in clinically and statistically significant efficacy in patients with CLBP.