Placebo Response Reduction and Accurate Pain Reporting Training Reduces Placebo Responses in a Clinical Trial on Chronic Low Back Pain: Results From a Comparison to the Literature

Assessment of Pain in Osteoarthritis of the Knee

Knee osteoarthritis (KOA) pain is a subjective and personal experience, making it challenging to characterise patients' experiences and assess their pain. In addition, there is no global standard for the assessment of pain in KOA. Therefore, this article examines the possible methods of assessing and characterising pain in patients with KOA using clinical symptoms, pain assessment tools, and imaging. We examine the current methods of assessment of pain in KOA and their application in clinical practice and clinical trials. Furthermore, we explore the possibility of creating individualised pain management plans to focus on different pain characteristics. With better evaluation and standardisation of pain assessment in these patients, it is hoped that patients would benefit from improved quality of life. At the same time, improvement in pain assessment would enable better data collection regarding symptom response in clinical trials for the treatment of osteoarthritis.

Relative efficacy of lasmiditan versus rimegepant and ubrogepant as acute treatments for migraine: network meta-analysis findings

Background

In the absence of head-to-head trials, comprehensive evidence comparing onset of efficacy of novel agents for acute treatment of migraine is lacking. This study aimed to explore the relative efficacy of lasmiditan (serotonin [5-hydroxytryptamine] 1F receptor agonist) versus rimegepant and ubrogepant (calcitonin gene-related peptide antagonists) for the acute oral treatment of migraine through network meta-analysis (NMA).

Methods

Data included in the NMA were identified through a systematic literature search (conducted April 2018, updated May/December 2020) of phase II–IV, randomised controlled trials (RCTs) in adults with chronic/episodic migraine with/without aura. Treatments included: lasmiditan 50, 100, 200 mg; rimegepant 75 mg; ubrogepant 25, 50, 100 mg. Pairwise treatment comparisons from Bayesian fixed-effect/random-effects NMA, adjusted by baseline risk where appropriate, were conducted. Comparisons were reported as odds ratios with 95% credible intervals. Early-onset efficacy endpoints included: pain freedom at 2 hours and pain relief at 1 and 2 hours. Adverse drug reaction (ADR) profiles were summarised. Heterogeneity and inconsistency in the network were explored; sensitivity analyses investigated robustness of findings.

Results

Across 12 RCTs included in the base case, females represented >80% of included patients (mean age 37.9–45.7 years). Odds of achieving both pain freedom and pain relief at 2 hours were higher with lasmiditan 100 and 200 mg versus rimegepant 75 mg and ubrogepant 25 and 50 mg. Results for pain relief at 1 hour were consistent with those at 2 hours, but fewer comparisons were available. There were no statistically significant differences between lasmiditan 50 mg and ubrogepant or rimegepant for any outcome. Sensitivity analyses were in the same direction as base case analyses. Most commonly reported ADRs (incidence ≥2%) were: dizziness, fatigue, paraesthesia, sedation, nausea/vomiting and muscle weakness with lasmiditan; nausea with rimegepant; and nausea, somnolence and dry mouth with ubrogepant.

Conclusions

The efficacy findings of this indirect comparison indicate that lasmiditan 100 mg or 200 mg might be an appropriate acute treatment option for patients with migraine seeking a fast onset of action. Differently from rimegepant and ubrogepant, lasmiditan use is associated with mainly neurological events, which are mostly mild or moderate in severity and self-limiting.

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Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01440-w.

Great Expectations: recommendations for improving the methodological rigor of psychedelic clinical trials

RATIONALE

Psychedelic research continues to garner significant public and scientific interest with a growing number of clinical studies examining a wide range of conditions and disorders. However, expectancy effects and effective condition masking have been raised as critical limitations to the interpretability of the research.

OBJECTIVE

In this article, we review the many methodological challenges of conducting psychedelic clinical trials and provide recommendations for improving the rigor of future research.

RESULTS

Although some challenges are shared with psychotherapy and pharmacology trials more broadly, psychedelic clinical trials have to contend with several unique sources of potential bias. The subjective effects of a high-dose psychedelic are often so pronounced that it is difficult to mask participants to their treatment condition; the significant hype from positive media coverage on the clinical potential of psychedelics influences participants' expectations for treatment benefit; and participant unmasking and treatment expectations can interact in such a way that makes psychedelic therapy highly susceptible to large placebo and nocebo effects. Specific recommendations to increase the success of masking procedures and reduce the influence of participant expectancies are discussed in the context of study development, participant recruitment and selection, incomplete disclosure of the study design, choice of active placebo condition, as well as the measurement of participant expectations and masking efficacy.

CONCLUSION

Incorporating the recommended design elements is intended to reduce the risk of bias in psychedelic clinical trials and thereby increases the ability to discern treatment-specific effects of psychedelic therapy.

Associations Between Interindividual Differences, Expectations and Placebo and Nocebo Effects in Itch

Introduction: Placebo and nocebo effects are positive and negative health outcomes that can be elicited by the psychosocial context. They can be mediated by expectations, and may emerge in somatic symptoms even when people are aware of these effects. Interindividual differences (e.g., in personality, affective states) could impact placebo and nocebo responding, but findings are inconsistent. Methods: The current work examined expectation as a mediator of the association between verbal placebo and nocebo suggestions (VSs) and histamine-induced itch across three experimental studies. Moreover, we examined whether interindividual differences (e.g., in optimism, neuroticism, behavioral activation system (BAS), body ignorance) modulated: (1) the direct association between VSs and itch (direct moderation), and (2) the indirect, expectation-mediated association between VSs and itch (moderated mediation). Positive VSs were compared to neutral instructions (Study 1; n = 92) or negative VSs (Studies 2+3; n = 203) in an open-label (i.e., explaining placebo and nocebo effects) or closed-label (concealed) context using PROCESS. First, mediation of VSs effects on itch by expectations was tested. Next, moderation by individual traits was explored using conditional process analyses. Results: The effects of VSs on itch were significantly mediated by expectation in Study 1 and in the open-label (but not closed-label) contexts of Studies 2 and 3. Ignorance of bodily signals marginally moderated the direct effects of VSs on itch when closed-label suggestions were given: at low levels of body ignorance, effects of positive and negative VSs were stronger. Moreover, moderated mediation was observed in the open-label groups of Studies 2 and 3: The expectation-mediated effects of VSs on itch were stronger when BAS drive was lower. Conclusion: Overall, the effects of VSs on itch were mediated by expectations in the open-label, but not the closed-label context. Moreover, the current work suggests that placebo and nocebo effects may be moderated by ignorance of bodily signals and the BAS. There was limited evidence that other interindividual differences modulated placebo and nocebo responding in itch.

Advances in the treatment of neuropathic pain

PURPOSE OF REVIEW

Neuropathic pain remains difficult to treat. This review provides an update regarding recent advances in therapeutic management, particularly with regards to newer drugs, neurostimulation techniques and original study designs.

RECENT FINDINGS

Although the mainstay of neuropathic pain management is still represented by drug therapy, particularly antidepressants and antiepileptics, the place of nonpharmacological therapy including in particular brain neuromodulation techniques has substantially increased in recent years. Newer study designs are also increasingly implemented, based on in depth phenotypic profiling to achieve more individualized therapy, or on screening strategies to decrease placebo effect and contribute to increase assay sensitivity. These approaches are now considered the most promising to decrease therapeutic failures in neuropathic pain.

SUMMARY

Neuropathic pain management should not be restricted to pharmacotherapy but now encompasses multiple approaches including particularly neuromodulation techniques. Multimodal assessment can also help identify predictors of the response in clinical trials in order to ensure appropriate management.

Design and conduct of confirmatory chronic pain clinical trials

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.